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Mild cognitive impairment (MCI) in long-term care patients: subtype classification and occurrence a
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William E. Mansbach , Ryan A. Mace & Kristen M. Clark a
Mansbach Health Tools, LLC, Simpsonville, MD, USA Published online: 30 Jan 2015.
Click for updates To cite this article: William E. Mansbach, Ryan A. Mace & Kristen M. Clark (2015): Mild cognitive impairment (MCI) in longterm care patients: subtype classification and occurrence, Aging & Mental Health, DOI: 10.1080/13607863.2014.1003283 To link to this article: http://dx.doi.org/10.1080/13607863.2014.1003283
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Aging & Mental Health, 2015 http://dx.doi.org/10.1080/13607863.2014.1003283
Mild cognitive impairment (MCI) in long-term care patients: subtype classification and occurrence William E. Mansbach*, Ryan A. Mace and Kristen M. Clark Mansbach Health Tools, LLC, Simpsonville, MD, USA
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(Received 20 August 2014; accepted 23 December 2014) Objectives: This study examines mild cognitive impairment (MCI) in long-term care settings by identifying and quantifying MCI subtypes in a combined sample of nursing home and assisted-living patients. We compared impairment thresholds of 1-SD and 1.5-SD to determine if different cut-offs differentially affect occurrence rates. Method: One hundred and eight participants who met general criteria for MCI were included for the purposes of this study. The general diagnosis of MCI was based on criteria. Participants were further grouped into MCI subtypes. Based on previously established norms, Brief Cognitive Assessment Tool (BCAT) factor scores were used to assess whether MCI participants met either the 1-SD and 1.5-SD impairment thresholds for memory, executive functions, and attentional capacity. Results: Using both 1-SD and 1.5-SD impairment thresholds, three clear MCI subtypes were identified: amnestic, singledomain; non-amnestic, single-domain (executive); and amnestic, multi-domain (memory and executive). A fourth category (undifferentiated) was identified in patients who did not meet criteria for a distinct MCI subtype, but still had cognitive impairments. The stricter impairment threshold of 1.5-SD resulted in fewer patients classified as having any of the three domain-specific subtypes. Conclusion: Based on a sample of nursing home and assisted-living patients, we identified three MCI subtypes, and a fourth category consisting of participants with general MCI, but without clear evidence of domain-specific cognitive impairment. When selecting impairment thresholds, one should consider the impact on the identification of MCI subtypes and the probability of misdiagnoses. Keywords: mild cognitive impairment; cognitive assessment; long-term care; BCAT
Introduction During the past 15 years, clinical interest and research concerning the construct of mild cognitive impairment (MCI) has rapidly expanded (Arsenault-Lapierre et al., 2011; Busse, Hensel, G€ uhne, Angermeyer, & RiedelHeller, 2006; Portet et al., 2006). First introduced by Reisberg et al. as part of the Global Deterioration Scale (Reisberg, Ferris, de Leon, & Crook, 1988), the construct has undergone significant revisions. Perhaps the most prominent advances have come from the seminal studies by Petersen and co-workers (Petersen et al., 1997; Petersen et al., 1999), in which general criteria for the syndrome were first posited, and later by the International (European) Working Group on Mild Cognitive Impairment in Stockholm, Sweden (Winblad et al., 2004). The European consortium was among the first to articulate MCI subtypes. Their work has formed the basis of a general consensus supporting four probable MCI subtypes (Petersen et al., 2009; Winblad et al., 2004): amnestic MCI, single domain; amnestic MCI, multi-domain; nonamnestic, multi-domain; and non-amnestic MCI, single domain. As research interest and clinical applications have grown, it has become apparent that MCI is a heterogeneous and complex construct. Debate continues as to whether subtypes have different etiologies and disease *Corresponding author. Email: [email protected] Ó 2015 Taylor & Francis
progressions, and questions remain as to subtype occurrence and prognosis (DeCarli, 2003; Fischer et al., 2007; Lopez et al., 2003; Maioli et al., 2007; Yaffe, Petersen, Lindquist, Kramer, & Miller, 2006). Certainly there is ambiguity regarding what cognitive tests to use, what impairment thresholds should be considered, and how norms may vary depending on population type. Diagnostic accuracy is particularly subject to the selection of impairment thresholds. For example, cut-scores of 1-SD versus 1.5-SD can differentially determine whether a patient is assigned a MCI subtype (Arsenault-Lapierre et al., 2011; Busse et al., 2006). The identification of MCI is further complicated by possible variance in prevalence and incidence estimates across different populations (Ward, Arrighi, Michels, & Cedarbaum, 2012). Relative to dementia, the MCI research literature is relatively recent, and one can reasonably argue that more studies are needed to further refine the construct. The majority of MCI research has focused on community-dwelling participants, and much less focus has been placed on residents of long-term care settings. Yet, in both nursing homes and assisted-living facilities, reported prevalence of cognitive impairment is high (Mansbach, MacDougall, Clark, & Mace, 2014; Rosenblatt et al., 2004). Questions remain regarding whether MCI subtypes found in community-dwelling patients are mirrored in
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long-term care settings, and how selected impairment thresholds might impact probable diagnosis. This study had two primary goals: (1) to quantify MCI in long-term care settings, by identifying MCI subtypes, and measure their respective occurrence in a combined sample of nursing home and assisted-living patients; and (2) to compare occurrence rates of MCI subtypes based on two commonly used impairment thresholds. Because previous research has indicated that amnestic and executive deficits are particularly common in long-term care patients (Mansbach, MacDougall et al., 2014; Mansbach, MacDougall, & Rosenzweig, 2012), and amnestic and executive subtypes have been identified in community samples (Reinvang, Gambaite, & Espeseth, 2012), we hypothesized that MCI subtypes specific to these cognitive domains would be identified in the sample. Therefore, we hypothesized that the three (Winblad et al., 2004) subtypes pertinent to amnestic and executive deficits would be confirmed: amnestic, single domain; amnestic, multidomain; and non-amnestic, single domain (executive). We did not attempt to confirm the fourth (Winblad et al., 2004) subtype: non-amnestic, multi-domain. This is because there is less empirical evidence in the literature for this subtype, and it requires co-occurrence of cognitive deficits that are less frequently observed in cognitively impaired long-term care patients. Based on the work of other researchers (Arsenault-Lapierre et al., 2011; Busse et al., 2006), we also hypothesized that different impairment thresholds would produce significantly different occurrence rates of MCI subtypes.
Table 1 Select demographics and diagnoses of participants (N D 108).
Methods Participants
Note: mild cognitive impairment (MCI). a Based on Geriatric Depression Scale Short Form (Sheikh & Yesavage, 1986) > 5 for self-reported depression.
A total of 477 individuals residing in a US skilled nursing facility (n D 315) and two US assisted-living facilities (n D 162) were referred for neuro-cognitive evaluation (October 2012 to March 2014). We compared these subjects from the nursing home and assisted-living facilities to determine if there were significant differences in cognitive diagnoses and key demographic variables. Non-significant chi-square tests for independence and independent sample t-tests indicated no significant differences between subjects from the nursing home and assisted-living subsamples. For the purposes of this study, the skilled nursing and assisted-living subsamples were combined for retrospective data analysis. One hundred and eight participants met inclusion criteria for retrospective data analysis, which required a completed Brief Cognitive Assessment Tool (BCAT), proficiency in English, age > 59, and a diagnosis of MCI based on criteria adapted from Petersen et al. (1997). Participants with medical or psychiatric impairments too severe for study participation were excluded. Participants ranged in age from 61 to 96, with a mean age of 79.59 (§8.96). As presented in Table 1, 62% of participants were female, 82% were Caucasian, 50% were widowed, 89% had at least 12 years of education, and 39% had completed post-secondary education. Using a Geriatric Depression Scale Short Form (GDS-SF) cut score of >5
Characteristic Gender Male Female Race Caucasian African-American Other Missing Marital status Single, never married Divorced Widowed Married Missing Education (years completed) 0 4 5 8 9 11 12 13 15 16 17 18 >18 Missing Depression diagnosisa No depression Depression
Number
Percent
41 67
38 62
88 18 1 1
81.5 16.7 .9 .9
6 14 54 29 5
5.6 13.0 50.0 26.9 4.6
1 3 5 30 26 21 19 2 1
.9 2.8 4.6 27.8 24.1 19.4 17.6 1.9 .9
71 37
68.3 31.7
for self-reported depression (Sheikh & Yesavage, 1986), 32% of participants showed evidence of depression, while 68% were categorized as no depression.
Procedure All procedures were approved by the facility Medical Ethics Committee and all participants completed appropriate informed consent agreements. All participants were referred by their primary care physicians for neuro-cognitive evaluation. A licensed psychologist with specific expertise in the evaluation and treatment of dementia and cognitive dysfunction conducted all neuro-cognitive evaluations, and assigned all diagnoses. Neuro-cognitive evaluations consisted of a clinical interview with the patient; family or familial caregiver interview; comprehensive medical chart review; and a brief neuro-cognitive battery of tests consisting of the BCAT (Mansbach et al., 2012), AD8 Dementia Screening Interview (Galvin et al., 2005), Kitchen Picture Test of Practical Judgment (KPT; Mansbach, MacDougall et al., 2014), GDS-SF (Sheikh & Yesavage, 1986), Cornell Scale for Depression in Dementia (CSDD; Alexopoulos, Abrams, Young, & Shamoian, 1988), and the Generalized Anxiety Disorder 7-item scale (GAD-7; Spitzer, Korenke, Williams, & L€owe, 2006).
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Aging & Mental Health The general diagnosis of MCI was based on the following criteria adapted from Petersen et al. (1997): (1) decline from a previously normal level of function as reported by participants and/or their family or other caregivers; (2) objective cognitive impairment based on an impairment threshold of 1-SD to 2-SD based on the BCAT; (3) relatively preserved everyday instrumental activities of daily living (IADL); (4) absence of dementia; and (5) no indication of delirium or psychiatric disorder that would explain current cognitive dysfunction. MCI participants were further subcategorized using subtype criteria recommended by Winblad et al. (2004). MCI subtypes had to have at least one cognitive domain test or factor score meeting the impairment threshold of 1-SD. Three specific cognitive domains were assessed: verbal memory, executive control functions, and attentional capacity. Based on previously established norms (MacDougall, Mansbach, Clark, & Mace, 2015), the BCAT Contextual Memory Factor (CMF), the BCAT Executive Control Functions Factor (ECFF), and the BCAT Attentional Capacity Factor (ACF) were used to assess whether MCI participants met either the 1-SD and the more conservative 1.5-SD impairment thresholds for memory, executive functions, and attentional capacity, respectively. The inter-rater reliability coefficient for the general diagnosis of MCI was r D .93. Measures The Brief Cognitive Assessment Tool (BCAT) The BCAT (Mansbach et al., 2012) is a 21-item, from 0 to 50 point instrument designed to assess cognitive functioning, and that can be individually administered (by provider or technician) in approximately 15 minutes. The BCAT produces a total score suggesting specific cognitive levels and yields a CMF score, an ECFF score, and an ACF score. Ranges for the CMF, ECFF, and ACF are 0 15, 0 7, and 0 8, respectively. All three were found to be significant predictors of cognitive diagnosis and IADLs (Mansbach et al., 2012). The BCAT CMF is comprised of both word list and story recall items, and the ECFF includes several diverse items capturing several types of executive skills (Mansbach, Mace, & Clark, 2014). Psychometric analyses confirmed strong evidence for internal reliability (Chronbach’s a D .92), test-retest reliability (r D .99), and evidence of the construct validity of BCAT score inferences through convergent, discriminant, and predictive validity analyses. The BCAT’s utility to identify dementia versus MCI was excellent, with a sensitivity of .99, a specificity of .77, and an area under the receiver operating curve (ROC) curve of .95 (Mansbach et al., 2012). The BCAT has been validated in assisted-living facilities (Mansbach et al., 2012), skilled nursing facilities (Mansbach, Mace, & Clark, 2014), and community settings (MacDougall et al., 2015). Supplementary measures The AD8, a brief informant-based measure sensitive to the early signs of dementia, and the KPT, a visually presented test of judgment, were used alongside the BCAT in
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diagnosing MCI. The AD8 was designed to assess memory, orientation, judgment, and function. Scores range from 0 to 8, with scores of 2 or higher predicting a likelihood of dementia in a sample of older adults with a 38% base rate of very mild dementia. The AD8 has been found to improve identification of MCI (Galvin, Roe, & Morris, 2012), and it was used in this study to help determine the diagnosis of MCI. In addition to detecting problems in basic judgment, the KPT can significantly differentiate between demented and non-demented individuals with a suggested cut score of 7 (Mansbach, MacDougall et al., 2014). In two independent studies (study 1; N D 99 nursing home patients; study 2, N D 163 nursing home and assisted-living patients), psychometric analyses indicated strong evidence for reliability, construct validity, and predictive validity (Mansbach et al., 2012). In this study, the KPT was used as a diagnostic measure for identifying patients with MCI. A self-report (GDS-SF) and informant-based (CSDD) measure of depression and selfreport measure of anxiety (GAD-7) were used to assess mood functioning. Because depression and anxiety can negatively impact cognitive test scores, the mood measures were also used to detect possible false positive diagnoses of MCI due to mood impairment. The GDS-SF is likely the most commonly used scale to screen for depression in older adults. Scores range from 0 to 15, with higher scores indicating a greater likelihood of depression. Additionally, CSDD was incorporated in this study to balance the reports from dementia patients who may not be reliable informants. The 19-item CSDD addresses five domains of depression, based on information from two semi-structured interviews (from the patient and an informant), with scores ranging from 0 to 38. The GAD-7 was included in this study as anxiety symptoms frequently occur in long-term care patients (Smalbrugge, Pot, Jongenelis, Beekman, & Eefsting, 2005). Scores range from 0 to 27, and recommended cut points of the GAD-7 has been shown to identify generalized anxiety disorder in older adults (Wild et al., 2013). Statistical analysis All statistical analyses were performed using SPSS. Descriptive statistics were used to report participant demographics and frequency of MCI subtype diagnoses. McNemar’s test was conducted to determine whether the use of different impairment thresholds significantly changed the proportion of participants diagnosed among the MCI subtypes. Results Participants in this study were nursing home and assistedliving residents referred for neuro-cognitive evaluation. One hundred and eight, or 24.2%, of referred patients met general criteria for MCI. Three MCI subtypes were identified in the 108 participants diagnosed as having MCI: amnestic, single-domain; non-amnestic, single-domain (executive); and amnestic, multi-domain (memory and executive). For each, patients had a deficit in at least one BCAT cognitive domain below the 1-SD impairment
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Table 2. Descriptive statistics of the BCAT and BCAT factor scores.
Table 4. Descriptive statistics of MCI subtypes using 1.5-SD diagnostic thresholds.
Measure BCAT CMF ECFF ACF
Median
Mean
SD
Range
MCI subtype
39 13 6 6
38.02 12.58 5.23 5.86
3.61 1.68 1.58 1.03
27 6 0 3
Amnestic 47 43.5 Executive 8 7.4 Multi-domain 4 3.7 Undifferentiated 49 45.4
45 15 7 7
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Note: BCAT (Brief Cognitive Assessment Tool); CMF (BCAT Contextual Memory Factor); ECFF (BCAT Executive Control Functions Factor); ACF (BCAT Attentional Capacity Factor).
threshold. Descriptive statistics of the BCAT and BCAT factor scores for the MCI subsample are presented in Table 2. These categories are consistent with three of the Winblad et al. (2004) subtype categories. Their fourth subtype, non-amnestic, multi-domain, was not confirmed. Instead, this study identified another category in which patients met general criteria for MCI (Petersen et al., 1997), had a subjective cognitive complaint, but did not fall below the 1-SD impairment threshold. We describe them as having undifferentiated MCI. As reported in Table 3, 53.7% of participants had amnestic MCI, 11.1% had executive MCI, 14.8% had multi-domain MCI, and 20.4% had undifferentiated MCI based on 1-SD impairment thresholds. As reported in Table 4, 43.5% of participants had amnestic MCI, 7.4% had executive MCI, 3.7% had multi-domain MCI, and 45.4% had undifferentiated MCI based on 1.5-SD impairment thresholds. McNemar’s tests were conducted to determine whether the use of different impairment thresholds significantly changed the occurrence of MCI subclassifications (i.e., amnestic, executive, multi-domain, and undifferentiated). There was a statistically significant difference in the proportion of participants identified in the MCI subclassifications between the 1-SD and 1.5-SD thresholds [McNemar’s exact test (5, 108) D 35.00, p < .001]. Tables 3 and 4 also illustrate that the absolute number of participants identified in all four subclassifications changed between 1-SD and 1.5-SD thresholds. Specifically, there was a statistically significant difference in the occurrence of amnestic MCI (p D .04), multi-domain MCI (p D .00), and undifferentiated (p D .00) between the 1-SD and 1.5-SD impairment thresholds. However, there was no significant change in the proportion of participants classified as executive MCI (p D .29) between the 1-SD and 1.5-SD impairment thresholds. Table 3. Descriptive statistics of MCI subtypes using 1-SD diagnostic thresholds. MCI subtype
n Percent CMF M CMF SD ECFF M ECFF SD
Amnestic 58 Executive 12 Multi-domain 16 Undifferentiated 22
53.7 11.1 14.8 20.4
11.76 14.25 11.69 14.50
1.20 0.45 1.74 0.51
6.02 3.08 3.06 5.91
0.78 1.08 1.39 0.81
Note: amnestic (amnestic, single domain); executive (non-amnestic, single domain); multi-domain (amnestic, multi-domain); CMF (BCAT Contextual Memory Factor); ECFF (BCAT Executive Control Functions Factor).
n Percent CMF M CMF SD ECFF M ECFF SD 11.26 13.75 10.25 13.86
1.01 0.46 2.87 0.84
5.81 1.88 1.75 5.51
1.0 0.83 1.26 1.06
Note: amnestic (amnestic, single domain); executive (non-amnestic, single domain); multi-domain (amnestic, multi-domain); CMF (BCAT Contextual Memory Factor); ECFF (BCAT Executive Control Functions Factor).
Discussion We attempted to quantify MCI in long-term care settings, by identifying MCI subtypes, and measuring their respective occurrence in a combined sample of nursing home and assisted-living patients. We hypothesized that amnestic and executive subtypes would be identified. This supposition was based on previously reported high rates of memory impairment in these populations (CMS, 2013; Rosenblatt et al., 2004), and on previous research that has confirmed amnestic and executive MCI categories in other older adult populations (Delano-Wood et al., 2009). Using both 1-SD and 1.5-SD impairment thresholds, three clear MCI subtypes were identified: amnestic MCI, single domain; amnestic MCI, multi-domain (in which patients had both memory and executive impairment); and nonamnestic MCI, single domain (executive). These categories are generally consistent with three of the Winblad et al. (2004) subtypes, and provide evidence for both the executive subtype as a non-amnestic single domain MCI category, and as co-occurring with memory in the amnestic multi-domain subtype. We did not find evidence for a non-amnestic, multi-domain subtype, but this may be the result of not assessing all possible cognitive domains. Instead, we focused on the two domain-specific cognitive deficits most reported in the literature memory and executive functions (Mansbach et al., 2012). The fact that an executive subtype was identified, and that executive impairment was also found to be co-occurring with memory deficits, is consistent with reports of Rosenberg et al. (2011) and Reinvang et al. (2012). In our study, with both impairment thresholds, the most prevalent subtype was amnestic single domain. Using the 1-SD standard, approximately twice as many patients were classified as having amnestic MCI single domain than executive single domain and multi-domain combined; and at the 1.5-SD cut-off, amnestic MCI was approximately 3.5 times more prevalent than combined executive and multi-domain subtypes. The 1-SD ratio was similar to the 2:1 ratio of amnestic MCI to non-amnestic MCI reported by Petersen et al. (2009) in their review of the MCI literature. Furthermore, our finding that more patients were classified as single domain than multi-domain is consistent with the findings of Busse et al. (2006). However, whereas we found that amnestic MCI single domain was the most frequent subtype, Busse et al. (2006) found roughly equivalent prevalence between amnestic and nonamnestic subtypes.
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Aging & Mental Health We also identified a fourth category of participants who had modest cognitive impairments; had a total BCAT score in the MCI range, but did not meet the minimum 1-SD impairment threshold on any BCAT factor score; and met the general MCI criteria (Petersen et al., 1997). From a clinical perspective, these patients could be classified as having general or undifferentiated MCI (i.e., MCI without subtype). It is possible that this group represents patients who may, over time, develop a clear subtype. This would be consistent with conceptualizing MCI as a progressive stage toward dementia. However, given that they are close to normal functioning, they may instead represent a category of MCI patients who revert to normal functioning. Previous researchers have documented that 20% or more of MCI patients demonstrate normal cognitive functioning when subsequently reevaluated (Gao et al., 2014; Koepsell & Monsell, 2012). Longitudinal analyses would be necessary to better understand this category of patients. One of the goals of the study was to compare impairment thresholds of 1-SD and 1.5-SD to determine if these two frequently used cut-offs differentially affected occurrence rates. As anticipated, we found that subtype identification was meaningfully impacted by impairment threshold selection. This finding is consistent with Arsenault-Lapierre et al. (2011), who similarly found that the selection of different impairment thresholds dramatically altered MCI subcategory diagnosis. In this study, the stricter impairment threshold of 1.5-SD resulted in fewer patients classified as having amnestic and multi-domain MCI. Conversely, proportionately more patients were classified as having undifferentiated MCI. Based on the 1.5-SD standard, patients had to demonstrate more impairment, reflected by lower BCAT factor scores, than based on the more liberal 1-SD threshold. In selecting impairment thresholds, one should consider the impact on test variability and the probability of misdiagnoses. As Busse et al. (2006) point out, selection of impairment thresholds may impact the variability of the tests used to determine MCI subtypes (e.g., lower cut-off scores tend to be associated with less variability), and differentially impact false positive rates (e.g., the more liberal the impairment threshold, the higher the likelihood of a false positive). We recommend the more conservative approach of selecting the 1.5SD impairment threshold, which minimizes the likelihood that clinicians will say that patients have MCI subtypes when they in fact do not. Diagnoses that are false positive, can unduly alarm patients and their families and encourage clinicians to introduce interventions when they are not warranted. This is particularly important in long-term care settings, where delirium and medical comorbidities are common; patients who are diagnosed with MCI subtypes may revert to normal cognitive functioning with treatment of underlying medical conditions. Furthermore, a more conservative impairment threshold seems appropriate given that recognition of the MCI subtypes is still emerging, and more research is needed to fully understand its clinical importance. To best of our knowledge, this research is the first published long-term care study, based on both nursing
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home and assisted-living patients, to quantify MCI subtypes. In so doing, we present evidence that the selection of impairment thresholds does indeed significantly impact the occurrence of diagnosis subclassification. However, these findings should be considered in light of specific limitations to the study. First, while a short neuro-cognitive battery was used to make diagnoses and identify MCI categories, the number of tests used was limited. Second, the study was heavily based on the BCAT and BCAT cognitive domain factor scores. The BCAT was selected specifically because of the demonstrated utility of these factor scores in predicting cognitive diagnoses, and the fact that this test is frequently used in long-term settings. However, using other memory and executive functions tests may have produced different results, and future research using other tests could prove useful in confirming the MCI categories identified in the present study.
Disclosure statement No potential conflict of interest was reported by the authors.
References Alexopoulos, G.S., Abrams, R.C., Young, R.C., & Shamoian, C. A. (1988). Cornell scale for depression in dementia. Biological Psychiatry, 23(3), 271 284. doi:10.1016/0006-3223(88) 90038-8 Arsenault-Lapierre, G., Whitehead, V., Belleville, S., Massoud, F., Bergman, H., & Chertkow, H. (2011). Mild cognitive impairment subcategories depend on the source of norms. Journal of Clinical and Experimental Neuropsychology, 33 (5), 596 603. doi:10.1080/13803395.2010.547459 Busse, A., Hensel, A., G€ uhne, U., Angermeyer, M.C., & RiedelHeller, S.G. (2006). Mild cognitive impairment: Long-term course of four clinical subtypes. Neurology, 26(12), 2176 2185. doi:10.1212/01.wnl.0000249117.23318.e1 DeCarli, C. (2003). Mild cognitive impairment: Prevalence, prognosis, aetiology, and treatment. The Lancet Neurology, 2(1), 15 21. doi:10.1016/S1474-4422(03)00262-X Delano-Wood, L., Bondi, M.W., Sacco, J., Abeles, N., Jak, A.J., Libon, D.J., & Bozoki, A. (2009). Heterogeneity in mild cognitive impairment: Differences in neuropsychological profile and associated white matter lesion pathology. Journal of the International Neuropsychological Society, 15(6), 906 914. doi:10.1017/S1355617709990257 Department of Health and Human Services, Centers for Medicare & Medicaid Services. (2013). Nursing home data compendium. Retrieved August 27, 2013, from https://www. cms.gov/Medicare/Provider-Enrollment-and-Certification/ CertificationandComplianc/downloads/nursinghomedata compendium_508.pdf Fischer, P., Jungwirth, S., Zehetmayer, S., Weissgram, S., Hoenigschnabl, S., Gelpi, E. . . . Tragl, K.H. (2007). Conversion from subtypes of mild cognitive impairment to Alzheimer dementia. Neurology, 68(4), 288 291. doi:10.1212/01. wnl.0000252358.03285.9d Galvin, J.E., Roe, C.M., & Morris, J.C. (2012). The AD8 dementia screening test detects mild cognitive impairment. Alzheimer’s & Dementia: The Journal of the Alzheimer’s Association, 8(4), P483. doi: 10.1016/j.jalz.2012.05.1307 Galvin, J.E., Roe, C.M., Powlishta, K.K., Coats, M.A., Muich, S. J., Grant, E., . . . Morris, J.C. (2005). The AD8: A brief informant interview to detect dementia. Neurology, 65(4), 559 564.
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Gao, S., Unverzagt, F.W., Hall, K.S., Lane, K.A., Murrell, J.R., Hake, A.M., . . . Hendrie, H.C. (2014). Mild cognitive impairment, incidence, progression, and reversion: Findings from a community-based cohort of elderly African Americans. American Journal of Geriatric Psychiatry. 22(7), 670 681. doi:10.1016/j.jagp.2013.02.015 Koepsell, T.D., & Monsell, S.E. (2012). Reversion from mild cognitive impairment to normal or near-normal cognition: Risk factors and prognosis. Neurology, 79(15), 1591 1598. doi:10.1212/WNL.0b013e31826e26b7 Lopez, O.L., Jagust, W.J., DeKosky, S.T., Becker, J.T., Fitzpatrick, A., Dulberg, C., . . . Kuller, L.H. (2003). Prevalence and classification of mild cognitive impairment in the Cardiovascular Health Study Cognition Study: Part 1. Archives of Neurology, 60(10), 1385 1389. MacDougall, E.E., Mansbach, W.E., Clark, K.M., & Mace, R.A. (2015). The Brief Cognitive Assessment Tool (BCAT): Cross-validation in a community dwelling older adult sample. International Psychogeriatrics, 27(2), 243 250. doi:10.1017/S1041610214001458 Maioli, F., Coveri, M., Pagni, P., Chiandetti, C., Marchetti, C., Ciarrocchi, R., . . . Pedone, V. (2007). Conversion of mild cognitive impairment to dementia in elderly subjects: A preliminary study in a memory and cognitive disorder unit. Archives of Gerontology and Geriatrics, 44, 233 241. doi:10.1016/j.archger.2007.01.032 Mansbach, W.E., MacDougall, E.E., Clark, K.M., & Mace, R.A. (2014). Preliminary Investigation of the Kitchen Picture Test (KPT): A new screening test of practical judgment for older adults. Aging, Neuropsychology, and Cognition, 21(6), 674 692. doi:10.1080/13825585.2013.865698 Mansbach, W.E., MacDougall, E.E., & Rosenzweig, A.S. (2012). The Brief Cognitive Assessment Tool (BCAT): A new test emphasizing contextual memory, executive functions, attentional capacity, and the prediction of instrumental activities of daily living. Journal of Clinical and Experimental Neuropsychology, 34(2), 183 194. doi:10.1080/ 13803395.2011.630649 Mansbach, W.E., Mace, R.A., & Clark, K.M. (2014). Story recall and word lists: Differential and combined utilities in predicting cognitive diagnosis. Journal of Clinical and Experimental Neuropsychology, 36(6), 569 576. doi:10.1080/13803395. 2014.916656 Petersen, R.C., Roberts, R.O., Knopman, D.S., Boeve, B.F., Geda, Y.E., Ivnik, R.J., . . . Jack, C.R., Jr. (2009). Mild cognitive impairment: Ten years later. Archives of Neurology, 66(12), 1447 1455. doi:10.1001/archneurol.2009.266 Petersen, R.C., Smith, G.E., Waring, S.C., Ivnik, R.J., Kokmen, E., & Tangelos, E.G. (1997). Aging, memory, and mild cognitive impairment. International Psychogeriatrics, 9, 965 969. Petersen, R.C., Smith, G.E., Waring, S.C., Ivnik, R.J., Tangalos, E.G., & Kokmen, E. (1999). Mild cognitive impairment: Clinical characterization and outcome. Archives of Neurology, 56(3), 303 308. doi:10.1001/archneur.56.3.303 Portet, F., Ousset, P.J., Visser, P.J., Frisoni, G.B., Nobili, F., Scheltens, P., . . . Touchon, J. (2006). Mild cognitive
impairment (MCI) in medical practice: A critical review of the concept and new diagnostic procedure. Report of the MCI Working Group of the European Consortium on Alzheimer’s Disease. Journal of Neurology, Neurosurgery & Psychiatry, 77(6), 714 718. doi:10.1136/ jnnp.2005.085332 Reinvang, I., Grambaite, R., & Espeseth, T. (2012). Executive dysfunction in MCI: Subtype or early symptom. International Journal of Alzheimer’s Disease, 2012, 936272. doi:10.1155/2012/936272 Reisberg, B., Ferris, S.H., de Leon, M.J., & Crook, T. (1988). Global Deterioration Scale (GDS). Psychopharmacology Bulletin, 24(4), 661 663. Rosenberg, P.B., Mielke, M.M., Appleby, B., Oh, E., Leoutsakos, J.M., & Lyketsos, C.G. (2011). Neuropsychiatric symptoms in MCI subtypes: The importance of executive dysfunction. International Journal of Geriatric Psychiatry, 26(4), 364 372. doi:10.1002/gps.2535. Rosenblatt, A., Samus, Q.M., Steele, C.D., Baker, A.S., Harper, M.G., Brandt, J., . . . Lyketsos, C.G. (2004). The Maryland assisted living study: Prevalence, recognition, and treatment of dementia and other psychiatric disorder in the assisted living population of central Maryland. Journal of the American Geriatrics Society, 52(10), 1618 1625. Sheikh, J.I., & Yesavage, J.A. (1986). Geriatric Depression Scale (GDS): Recent evidence and development of a shorter version. Clinical Gerontology, 5, 165 173. doi:10.3109/ 09638288.2010.503835 Smalbrugge, M., Pot, A.M., Jongenelis, K., Beekman, A.T., & Eefsting, J.A. (2005). Prevalence and correlates of anxiety among nursing home patients. Journal of Affect Disorders, 88(2), 145 153. Spitzer, R.L., Kroenke, K., Williams, J.B., & L€ owe, B. (2006). A brief measure for assessing generalized anxiety disorder: The GAD-7. Archives of Internal Medicine, 166(10), 1092 1097. Ward, A., Arrighi, H.M., Michels, S., & Cedarbaum, J.M. (2012). Mild cognitive impairment: Disparity of incidence and prevalence rates. Alzheimer’s & Dementia: The Journal of the Alzheimer’s Association, 8(1), 14 21. doi: 10.1016/j. jalz.2011.01.002 Wild, B., Eckl, A., Herzog, W., Niehoff, D., Lechner, S., Maatouk, I., . . . L€ owe B. (2013). Assessing generalized anxiety disorder in elderly people using the GAD-7 and GAD-2 scales: Results of a validation study. American Journal of Geriatric Psychiatry, 22(10), 1029 1038. doi:10.1016/j. jagp.2013.01.076 Winblad, B., Palmer, K., Kivipelto, M., Jelic, V., Fratiglioni, L., Wahlund, L.O., . . . Petersen, R.C. (2004). Mild cognitive impairment—beyond controversies, towards a consensus: Report of the International Working Group on Mild Cognitive Impairment. Journal of Internal Medicine, 256(3), 240 246. Yaffe, K., Petersen, R.C., Lindquist, K., Kramer, J., & Miller B. (2006). Subtype of mild cognitive impairment and progression to dementia and death. Dementia and Geriatric Cognitive Disorders, 22(4), 312 319.
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Mild cognitive impairment (MCI) in long-term care patients: subtype classification and occurrence a
a
a
William E. Mansbach , Ryan A. Mace & Kristen M. Clark a
Mansbach Health Tools, LLC, Simpsonville, MD, USA Published online: 30 Jan 2015.
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Aging & Mental Health, 2015 http://dx.doi.org/10.1080/13607863.2014.1003283
Mild cognitive impairment (MCI) in long-term care patients: subtype classification and occurrence William E. Mansbach*, Ryan A. Mace and Kristen M. Clark Mansbach Health Tools, LLC, Simpsonville, MD, USA
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(Received 20 August 2014; accepted 23 December 2014) Objectives: This study examines mild cognitive impairment (MCI) in long-term care settings by identifying and quantifying MCI subtypes in a combined sample of nursing home and assisted-living patients. We compared impairment thresholds of 1-SD and 1.5-SD to determine if different cut-offs differentially affect occurrence rates. Method: One hundred and eight participants who met general criteria for MCI were included for the purposes of this study. The general diagnosis of MCI was based on criteria. Participants were further grouped into MCI subtypes. Based on previously established norms, Brief Cognitive Assessment Tool (BCAT) factor scores were used to assess whether MCI participants met either the 1-SD and 1.5-SD impairment thresholds for memory, executive functions, and attentional capacity. Results: Using both 1-SD and 1.5-SD impairment thresholds, three clear MCI subtypes were identified: amnestic, singledomain; non-amnestic, single-domain (executive); and amnestic, multi-domain (memory and executive). A fourth category (undifferentiated) was identified in patients who did not meet criteria for a distinct MCI subtype, but still had cognitive impairments. The stricter impairment threshold of 1.5-SD resulted in fewer patients classified as having any of the three domain-specific subtypes. Conclusion: Based on a sample of nursing home and assisted-living patients, we identified three MCI subtypes, and a fourth category consisting of participants with general MCI, but without clear evidence of domain-specific cognitive impairment. When selecting impairment thresholds, one should consider the impact on the identification of MCI subtypes and the probability of misdiagnoses. Keywords: mild cognitive impairment; cognitive assessment; long-term care; BCAT
Introduction During the past 15 years, clinical interest and research concerning the construct of mild cognitive impairment (MCI) has rapidly expanded (Arsenault-Lapierre et al., 2011; Busse, Hensel, G€ uhne, Angermeyer, & RiedelHeller, 2006; Portet et al., 2006). First introduced by Reisberg et al. as part of the Global Deterioration Scale (Reisberg, Ferris, de Leon, & Crook, 1988), the construct has undergone significant revisions. Perhaps the most prominent advances have come from the seminal studies by Petersen and co-workers (Petersen et al., 1997; Petersen et al., 1999), in which general criteria for the syndrome were first posited, and later by the International (European) Working Group on Mild Cognitive Impairment in Stockholm, Sweden (Winblad et al., 2004). The European consortium was among the first to articulate MCI subtypes. Their work has formed the basis of a general consensus supporting four probable MCI subtypes (Petersen et al., 2009; Winblad et al., 2004): amnestic MCI, single domain; amnestic MCI, multi-domain; nonamnestic, multi-domain; and non-amnestic MCI, single domain. As research interest and clinical applications have grown, it has become apparent that MCI is a heterogeneous and complex construct. Debate continues as to whether subtypes have different etiologies and disease *Corresponding author. Email: [email protected] Ó 2015 Taylor & Francis
progressions, and questions remain as to subtype occurrence and prognosis (DeCarli, 2003; Fischer et al., 2007; Lopez et al., 2003; Maioli et al., 2007; Yaffe, Petersen, Lindquist, Kramer, & Miller, 2006). Certainly there is ambiguity regarding what cognitive tests to use, what impairment thresholds should be considered, and how norms may vary depending on population type. Diagnostic accuracy is particularly subject to the selection of impairment thresholds. For example, cut-scores of 1-SD versus 1.5-SD can differentially determine whether a patient is assigned a MCI subtype (Arsenault-Lapierre et al., 2011; Busse et al., 2006). The identification of MCI is further complicated by possible variance in prevalence and incidence estimates across different populations (Ward, Arrighi, Michels, & Cedarbaum, 2012). Relative to dementia, the MCI research literature is relatively recent, and one can reasonably argue that more studies are needed to further refine the construct. The majority of MCI research has focused on community-dwelling participants, and much less focus has been placed on residents of long-term care settings. Yet, in both nursing homes and assisted-living facilities, reported prevalence of cognitive impairment is high (Mansbach, MacDougall, Clark, & Mace, 2014; Rosenblatt et al., 2004). Questions remain regarding whether MCI subtypes found in community-dwelling patients are mirrored in
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long-term care settings, and how selected impairment thresholds might impact probable diagnosis. This study had two primary goals: (1) to quantify MCI in long-term care settings, by identifying MCI subtypes, and measure their respective occurrence in a combined sample of nursing home and assisted-living patients; and (2) to compare occurrence rates of MCI subtypes based on two commonly used impairment thresholds. Because previous research has indicated that amnestic and executive deficits are particularly common in long-term care patients (Mansbach, MacDougall et al., 2014; Mansbach, MacDougall, & Rosenzweig, 2012), and amnestic and executive subtypes have been identified in community samples (Reinvang, Gambaite, & Espeseth, 2012), we hypothesized that MCI subtypes specific to these cognitive domains would be identified in the sample. Therefore, we hypothesized that the three (Winblad et al., 2004) subtypes pertinent to amnestic and executive deficits would be confirmed: amnestic, single domain; amnestic, multidomain; and non-amnestic, single domain (executive). We did not attempt to confirm the fourth (Winblad et al., 2004) subtype: non-amnestic, multi-domain. This is because there is less empirical evidence in the literature for this subtype, and it requires co-occurrence of cognitive deficits that are less frequently observed in cognitively impaired long-term care patients. Based on the work of other researchers (Arsenault-Lapierre et al., 2011; Busse et al., 2006), we also hypothesized that different impairment thresholds would produce significantly different occurrence rates of MCI subtypes.
Table 1 Select demographics and diagnoses of participants (N D 108).
Methods Participants
Note: mild cognitive impairment (MCI). a Based on Geriatric Depression Scale Short Form (Sheikh & Yesavage, 1986) > 5 for self-reported depression.
A total of 477 individuals residing in a US skilled nursing facility (n D 315) and two US assisted-living facilities (n D 162) were referred for neuro-cognitive evaluation (October 2012 to March 2014). We compared these subjects from the nursing home and assisted-living facilities to determine if there were significant differences in cognitive diagnoses and key demographic variables. Non-significant chi-square tests for independence and independent sample t-tests indicated no significant differences between subjects from the nursing home and assisted-living subsamples. For the purposes of this study, the skilled nursing and assisted-living subsamples were combined for retrospective data analysis. One hundred and eight participants met inclusion criteria for retrospective data analysis, which required a completed Brief Cognitive Assessment Tool (BCAT), proficiency in English, age > 59, and a diagnosis of MCI based on criteria adapted from Petersen et al. (1997). Participants with medical or psychiatric impairments too severe for study participation were excluded. Participants ranged in age from 61 to 96, with a mean age of 79.59 (§8.96). As presented in Table 1, 62% of participants were female, 82% were Caucasian, 50% were widowed, 89% had at least 12 years of education, and 39% had completed post-secondary education. Using a Geriatric Depression Scale Short Form (GDS-SF) cut score of >5
Characteristic Gender Male Female Race Caucasian African-American Other Missing Marital status Single, never married Divorced Widowed Married Missing Education (years completed) 0 4 5 8 9 11 12 13 15 16 17 18 >18 Missing Depression diagnosisa No depression Depression
Number
Percent
41 67
38 62
88 18 1 1
81.5 16.7 .9 .9
6 14 54 29 5
5.6 13.0 50.0 26.9 4.6
1 3 5 30 26 21 19 2 1
.9 2.8 4.6 27.8 24.1 19.4 17.6 1.9 .9
71 37
68.3 31.7
for self-reported depression (Sheikh & Yesavage, 1986), 32% of participants showed evidence of depression, while 68% were categorized as no depression.
Procedure All procedures were approved by the facility Medical Ethics Committee and all participants completed appropriate informed consent agreements. All participants were referred by their primary care physicians for neuro-cognitive evaluation. A licensed psychologist with specific expertise in the evaluation and treatment of dementia and cognitive dysfunction conducted all neuro-cognitive evaluations, and assigned all diagnoses. Neuro-cognitive evaluations consisted of a clinical interview with the patient; family or familial caregiver interview; comprehensive medical chart review; and a brief neuro-cognitive battery of tests consisting of the BCAT (Mansbach et al., 2012), AD8 Dementia Screening Interview (Galvin et al., 2005), Kitchen Picture Test of Practical Judgment (KPT; Mansbach, MacDougall et al., 2014), GDS-SF (Sheikh & Yesavage, 1986), Cornell Scale for Depression in Dementia (CSDD; Alexopoulos, Abrams, Young, & Shamoian, 1988), and the Generalized Anxiety Disorder 7-item scale (GAD-7; Spitzer, Korenke, Williams, & L€owe, 2006).
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Aging & Mental Health The general diagnosis of MCI was based on the following criteria adapted from Petersen et al. (1997): (1) decline from a previously normal level of function as reported by participants and/or their family or other caregivers; (2) objective cognitive impairment based on an impairment threshold of 1-SD to 2-SD based on the BCAT; (3) relatively preserved everyday instrumental activities of daily living (IADL); (4) absence of dementia; and (5) no indication of delirium or psychiatric disorder that would explain current cognitive dysfunction. MCI participants were further subcategorized using subtype criteria recommended by Winblad et al. (2004). MCI subtypes had to have at least one cognitive domain test or factor score meeting the impairment threshold of 1-SD. Three specific cognitive domains were assessed: verbal memory, executive control functions, and attentional capacity. Based on previously established norms (MacDougall, Mansbach, Clark, & Mace, 2015), the BCAT Contextual Memory Factor (CMF), the BCAT Executive Control Functions Factor (ECFF), and the BCAT Attentional Capacity Factor (ACF) were used to assess whether MCI participants met either the 1-SD and the more conservative 1.5-SD impairment thresholds for memory, executive functions, and attentional capacity, respectively. The inter-rater reliability coefficient for the general diagnosis of MCI was r D .93. Measures The Brief Cognitive Assessment Tool (BCAT) The BCAT (Mansbach et al., 2012) is a 21-item, from 0 to 50 point instrument designed to assess cognitive functioning, and that can be individually administered (by provider or technician) in approximately 15 minutes. The BCAT produces a total score suggesting specific cognitive levels and yields a CMF score, an ECFF score, and an ACF score. Ranges for the CMF, ECFF, and ACF are 0 15, 0 7, and 0 8, respectively. All three were found to be significant predictors of cognitive diagnosis and IADLs (Mansbach et al., 2012). The BCAT CMF is comprised of both word list and story recall items, and the ECFF includes several diverse items capturing several types of executive skills (Mansbach, Mace, & Clark, 2014). Psychometric analyses confirmed strong evidence for internal reliability (Chronbach’s a D .92), test-retest reliability (r D .99), and evidence of the construct validity of BCAT score inferences through convergent, discriminant, and predictive validity analyses. The BCAT’s utility to identify dementia versus MCI was excellent, with a sensitivity of .99, a specificity of .77, and an area under the receiver operating curve (ROC) curve of .95 (Mansbach et al., 2012). The BCAT has been validated in assisted-living facilities (Mansbach et al., 2012), skilled nursing facilities (Mansbach, Mace, & Clark, 2014), and community settings (MacDougall et al., 2015). Supplementary measures The AD8, a brief informant-based measure sensitive to the early signs of dementia, and the KPT, a visually presented test of judgment, were used alongside the BCAT in
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diagnosing MCI. The AD8 was designed to assess memory, orientation, judgment, and function. Scores range from 0 to 8, with scores of 2 or higher predicting a likelihood of dementia in a sample of older adults with a 38% base rate of very mild dementia. The AD8 has been found to improve identification of MCI (Galvin, Roe, & Morris, 2012), and it was used in this study to help determine the diagnosis of MCI. In addition to detecting problems in basic judgment, the KPT can significantly differentiate between demented and non-demented individuals with a suggested cut score of 7 (Mansbach, MacDougall et al., 2014). In two independent studies (study 1; N D 99 nursing home patients; study 2, N D 163 nursing home and assisted-living patients), psychometric analyses indicated strong evidence for reliability, construct validity, and predictive validity (Mansbach et al., 2012). In this study, the KPT was used as a diagnostic measure for identifying patients with MCI. A self-report (GDS-SF) and informant-based (CSDD) measure of depression and selfreport measure of anxiety (GAD-7) were used to assess mood functioning. Because depression and anxiety can negatively impact cognitive test scores, the mood measures were also used to detect possible false positive diagnoses of MCI due to mood impairment. The GDS-SF is likely the most commonly used scale to screen for depression in older adults. Scores range from 0 to 15, with higher scores indicating a greater likelihood of depression. Additionally, CSDD was incorporated in this study to balance the reports from dementia patients who may not be reliable informants. The 19-item CSDD addresses five domains of depression, based on information from two semi-structured interviews (from the patient and an informant), with scores ranging from 0 to 38. The GAD-7 was included in this study as anxiety symptoms frequently occur in long-term care patients (Smalbrugge, Pot, Jongenelis, Beekman, & Eefsting, 2005). Scores range from 0 to 27, and recommended cut points of the GAD-7 has been shown to identify generalized anxiety disorder in older adults (Wild et al., 2013). Statistical analysis All statistical analyses were performed using SPSS. Descriptive statistics were used to report participant demographics and frequency of MCI subtype diagnoses. McNemar’s test was conducted to determine whether the use of different impairment thresholds significantly changed the proportion of participants diagnosed among the MCI subtypes. Results Participants in this study were nursing home and assistedliving residents referred for neuro-cognitive evaluation. One hundred and eight, or 24.2%, of referred patients met general criteria for MCI. Three MCI subtypes were identified in the 108 participants diagnosed as having MCI: amnestic, single-domain; non-amnestic, single-domain (executive); and amnestic, multi-domain (memory and executive). For each, patients had a deficit in at least one BCAT cognitive domain below the 1-SD impairment
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Table 2. Descriptive statistics of the BCAT and BCAT factor scores.
Table 4. Descriptive statistics of MCI subtypes using 1.5-SD diagnostic thresholds.
Measure BCAT CMF ECFF ACF
Median
Mean
SD
Range
MCI subtype
39 13 6 6
38.02 12.58 5.23 5.86
3.61 1.68 1.58 1.03
27 6 0 3
Amnestic 47 43.5 Executive 8 7.4 Multi-domain 4 3.7 Undifferentiated 49 45.4
45 15 7 7
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Note: BCAT (Brief Cognitive Assessment Tool); CMF (BCAT Contextual Memory Factor); ECFF (BCAT Executive Control Functions Factor); ACF (BCAT Attentional Capacity Factor).
threshold. Descriptive statistics of the BCAT and BCAT factor scores for the MCI subsample are presented in Table 2. These categories are consistent with three of the Winblad et al. (2004) subtype categories. Their fourth subtype, non-amnestic, multi-domain, was not confirmed. Instead, this study identified another category in which patients met general criteria for MCI (Petersen et al., 1997), had a subjective cognitive complaint, but did not fall below the 1-SD impairment threshold. We describe them as having undifferentiated MCI. As reported in Table 3, 53.7% of participants had amnestic MCI, 11.1% had executive MCI, 14.8% had multi-domain MCI, and 20.4% had undifferentiated MCI based on 1-SD impairment thresholds. As reported in Table 4, 43.5% of participants had amnestic MCI, 7.4% had executive MCI, 3.7% had multi-domain MCI, and 45.4% had undifferentiated MCI based on 1.5-SD impairment thresholds. McNemar’s tests were conducted to determine whether the use of different impairment thresholds significantly changed the occurrence of MCI subclassifications (i.e., amnestic, executive, multi-domain, and undifferentiated). There was a statistically significant difference in the proportion of participants identified in the MCI subclassifications between the 1-SD and 1.5-SD thresholds [McNemar’s exact test (5, 108) D 35.00, p < .001]. Tables 3 and 4 also illustrate that the absolute number of participants identified in all four subclassifications changed between 1-SD and 1.5-SD thresholds. Specifically, there was a statistically significant difference in the occurrence of amnestic MCI (p D .04), multi-domain MCI (p D .00), and undifferentiated (p D .00) between the 1-SD and 1.5-SD impairment thresholds. However, there was no significant change in the proportion of participants classified as executive MCI (p D .29) between the 1-SD and 1.5-SD impairment thresholds. Table 3. Descriptive statistics of MCI subtypes using 1-SD diagnostic thresholds. MCI subtype
n Percent CMF M CMF SD ECFF M ECFF SD
Amnestic 58 Executive 12 Multi-domain 16 Undifferentiated 22
53.7 11.1 14.8 20.4
11.76 14.25 11.69 14.50
1.20 0.45 1.74 0.51
6.02 3.08 3.06 5.91
0.78 1.08 1.39 0.81
Note: amnestic (amnestic, single domain); executive (non-amnestic, single domain); multi-domain (amnestic, multi-domain); CMF (BCAT Contextual Memory Factor); ECFF (BCAT Executive Control Functions Factor).
n Percent CMF M CMF SD ECFF M ECFF SD 11.26 13.75 10.25 13.86
1.01 0.46 2.87 0.84
5.81 1.88 1.75 5.51
1.0 0.83 1.26 1.06
Note: amnestic (amnestic, single domain); executive (non-amnestic, single domain); multi-domain (amnestic, multi-domain); CMF (BCAT Contextual Memory Factor); ECFF (BCAT Executive Control Functions Factor).
Discussion We attempted to quantify MCI in long-term care settings, by identifying MCI subtypes, and measuring their respective occurrence in a combined sample of nursing home and assisted-living patients. We hypothesized that amnestic and executive subtypes would be identified. This supposition was based on previously reported high rates of memory impairment in these populations (CMS, 2013; Rosenblatt et al., 2004), and on previous research that has confirmed amnestic and executive MCI categories in other older adult populations (Delano-Wood et al., 2009). Using both 1-SD and 1.5-SD impairment thresholds, three clear MCI subtypes were identified: amnestic MCI, single domain; amnestic MCI, multi-domain (in which patients had both memory and executive impairment); and nonamnestic MCI, single domain (executive). These categories are generally consistent with three of the Winblad et al. (2004) subtypes, and provide evidence for both the executive subtype as a non-amnestic single domain MCI category, and as co-occurring with memory in the amnestic multi-domain subtype. We did not find evidence for a non-amnestic, multi-domain subtype, but this may be the result of not assessing all possible cognitive domains. Instead, we focused on the two domain-specific cognitive deficits most reported in the literature memory and executive functions (Mansbach et al., 2012). The fact that an executive subtype was identified, and that executive impairment was also found to be co-occurring with memory deficits, is consistent with reports of Rosenberg et al. (2011) and Reinvang et al. (2012). In our study, with both impairment thresholds, the most prevalent subtype was amnestic single domain. Using the 1-SD standard, approximately twice as many patients were classified as having amnestic MCI single domain than executive single domain and multi-domain combined; and at the 1.5-SD cut-off, amnestic MCI was approximately 3.5 times more prevalent than combined executive and multi-domain subtypes. The 1-SD ratio was similar to the 2:1 ratio of amnestic MCI to non-amnestic MCI reported by Petersen et al. (2009) in their review of the MCI literature. Furthermore, our finding that more patients were classified as single domain than multi-domain is consistent with the findings of Busse et al. (2006). However, whereas we found that amnestic MCI single domain was the most frequent subtype, Busse et al. (2006) found roughly equivalent prevalence between amnestic and nonamnestic subtypes.
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Aging & Mental Health We also identified a fourth category of participants who had modest cognitive impairments; had a total BCAT score in the MCI range, but did not meet the minimum 1-SD impairment threshold on any BCAT factor score; and met the general MCI criteria (Petersen et al., 1997). From a clinical perspective, these patients could be classified as having general or undifferentiated MCI (i.e., MCI without subtype). It is possible that this group represents patients who may, over time, develop a clear subtype. This would be consistent with conceptualizing MCI as a progressive stage toward dementia. However, given that they are close to normal functioning, they may instead represent a category of MCI patients who revert to normal functioning. Previous researchers have documented that 20% or more of MCI patients demonstrate normal cognitive functioning when subsequently reevaluated (Gao et al., 2014; Koepsell & Monsell, 2012). Longitudinal analyses would be necessary to better understand this category of patients. One of the goals of the study was to compare impairment thresholds of 1-SD and 1.5-SD to determine if these two frequently used cut-offs differentially affected occurrence rates. As anticipated, we found that subtype identification was meaningfully impacted by impairment threshold selection. This finding is consistent with Arsenault-Lapierre et al. (2011), who similarly found that the selection of different impairment thresholds dramatically altered MCI subcategory diagnosis. In this study, the stricter impairment threshold of 1.5-SD resulted in fewer patients classified as having amnestic and multi-domain MCI. Conversely, proportionately more patients were classified as having undifferentiated MCI. Based on the 1.5-SD standard, patients had to demonstrate more impairment, reflected by lower BCAT factor scores, than based on the more liberal 1-SD threshold. In selecting impairment thresholds, one should consider the impact on test variability and the probability of misdiagnoses. As Busse et al. (2006) point out, selection of impairment thresholds may impact the variability of the tests used to determine MCI subtypes (e.g., lower cut-off scores tend to be associated with less variability), and differentially impact false positive rates (e.g., the more liberal the impairment threshold, the higher the likelihood of a false positive). We recommend the more conservative approach of selecting the 1.5SD impairment threshold, which minimizes the likelihood that clinicians will say that patients have MCI subtypes when they in fact do not. Diagnoses that are false positive, can unduly alarm patients and their families and encourage clinicians to introduce interventions when they are not warranted. This is particularly important in long-term care settings, where delirium and medical comorbidities are common; patients who are diagnosed with MCI subtypes may revert to normal cognitive functioning with treatment of underlying medical conditions. Furthermore, a more conservative impairment threshold seems appropriate given that recognition of the MCI subtypes is still emerging, and more research is needed to fully understand its clinical importance. To best of our knowledge, this research is the first published long-term care study, based on both nursing
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home and assisted-living patients, to quantify MCI subtypes. In so doing, we present evidence that the selection of impairment thresholds does indeed significantly impact the occurrence of diagnosis subclassification. However, these findings should be considered in light of specific limitations to the study. First, while a short neuro-cognitive battery was used to make diagnoses and identify MCI categories, the number of tests used was limited. Second, the study was heavily based on the BCAT and BCAT cognitive domain factor scores. The BCAT was selected specifically because of the demonstrated utility of these factor scores in predicting cognitive diagnoses, and the fact that this test is frequently used in long-term settings. However, using other memory and executive functions tests may have produced different results, and future research using other tests could prove useful in confirming the MCI categories identified in the present study.
Disclosure statement No potential conflict of interest was reported by the authors.
References Alexopoulos, G.S., Abrams, R.C., Young, R.C., & Shamoian, C. A. (1988). Cornell scale for depression in dementia. Biological Psychiatry, 23(3), 271 284. doi:10.1016/0006-3223(88) 90038-8 Arsenault-Lapierre, G., Whitehead, V., Belleville, S., Massoud, F., Bergman, H., & Chertkow, H. (2011). Mild cognitive impairment subcategories depend on the source of norms. Journal of Clinical and Experimental Neuropsychology, 33 (5), 596 603. doi:10.1080/13803395.2010.547459 Busse, A., Hensel, A., G€ uhne, U., Angermeyer, M.C., & RiedelHeller, S.G. (2006). Mild cognitive impairment: Long-term course of four clinical subtypes. Neurology, 26(12), 2176 2185. doi:10.1212/01.wnl.0000249117.23318.e1 DeCarli, C. (2003). Mild cognitive impairment: Prevalence, prognosis, aetiology, and treatment. The Lancet Neurology, 2(1), 15 21. doi:10.1016/S1474-4422(03)00262-X Delano-Wood, L., Bondi, M.W., Sacco, J., Abeles, N., Jak, A.J., Libon, D.J., & Bozoki, A. (2009). Heterogeneity in mild cognitive impairment: Differences in neuropsychological profile and associated white matter lesion pathology. Journal of the International Neuropsychological Society, 15(6), 906 914. doi:10.1017/S1355617709990257 Department of Health and Human Services, Centers for Medicare & Medicaid Services. (2013). Nursing home data compendium. Retrieved August 27, 2013, from https://www. cms.gov/Medicare/Provider-Enrollment-and-Certification/ CertificationandComplianc/downloads/nursinghomedata compendium_508.pdf Fischer, P., Jungwirth, S., Zehetmayer, S., Weissgram, S., Hoenigschnabl, S., Gelpi, E. . . . Tragl, K.H. (2007). Conversion from subtypes of mild cognitive impairment to Alzheimer dementia. Neurology, 68(4), 288 291. doi:10.1212/01. wnl.0000252358.03285.9d Galvin, J.E., Roe, C.M., & Morris, J.C. (2012). The AD8 dementia screening test detects mild cognitive impairment. Alzheimer’s & Dementia: The Journal of the Alzheimer’s Association, 8(4), P483. doi: 10.1016/j.jalz.2012.05.1307 Galvin, J.E., Roe, C.M., Powlishta, K.K., Coats, M.A., Muich, S. J., Grant, E., . . . Morris, J.C. (2005). The AD8: A brief informant interview to detect dementia. Neurology, 65(4), 559 564.
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6
W.E. Mansbach et al.
Gao, S., Unverzagt, F.W., Hall, K.S., Lane, K.A., Murrell, J.R., Hake, A.M., . . . Hendrie, H.C. (2014). Mild cognitive impairment, incidence, progression, and reversion: Findings from a community-based cohort of elderly African Americans. American Journal of Geriatric Psychiatry. 22(7), 670 681. doi:10.1016/j.jagp.2013.02.015 Koepsell, T.D., & Monsell, S.E. (2012). Reversion from mild cognitive impairment to normal or near-normal cognition: Risk factors and prognosis. Neurology, 79(15), 1591 1598. doi:10.1212/WNL.0b013e31826e26b7 Lopez, O.L., Jagust, W.J., DeKosky, S.T., Becker, J.T., Fitzpatrick, A., Dulberg, C., . . . Kuller, L.H. (2003). Prevalence and classification of mild cognitive impairment in the Cardiovascular Health Study Cognition Study: Part 1. Archives of Neurology, 60(10), 1385 1389. MacDougall, E.E., Mansbach, W.E., Clark, K.M., & Mace, R.A. (2015). The Brief Cognitive Assessment Tool (BCAT): Cross-validation in a community dwelling older adult sample. International Psychogeriatrics, 27(2), 243 250. doi:10.1017/S1041610214001458 Maioli, F., Coveri, M., Pagni, P., Chiandetti, C., Marchetti, C., Ciarrocchi, R., . . . Pedone, V. (2007). Conversion of mild cognitive impairment to dementia in elderly subjects: A preliminary study in a memory and cognitive disorder unit. Archives of Gerontology and Geriatrics, 44, 233 241. doi:10.1016/j.archger.2007.01.032 Mansbach, W.E., MacDougall, E.E., Clark, K.M., & Mace, R.A. (2014). Preliminary Investigation of the Kitchen Picture Test (KPT): A new screening test of practical judgment for older adults. Aging, Neuropsychology, and Cognition, 21(6), 674 692. doi:10.1080/13825585.2013.865698 Mansbach, W.E., MacDougall, E.E., & Rosenzweig, A.S. (2012). The Brief Cognitive Assessment Tool (BCAT): A new test emphasizing contextual memory, executive functions, attentional capacity, and the prediction of instrumental activities of daily living. Journal of Clinical and Experimental Neuropsychology, 34(2), 183 194. doi:10.1080/ 13803395.2011.630649 Mansbach, W.E., Mace, R.A., & Clark, K.M. (2014). Story recall and word lists: Differential and combined utilities in predicting cognitive diagnosis. Journal of Clinical and Experimental Neuropsychology, 36(6), 569 576. doi:10.1080/13803395. 2014.916656 Petersen, R.C., Roberts, R.O., Knopman, D.S., Boeve, B.F., Geda, Y.E., Ivnik, R.J., . . . Jack, C.R., Jr. (2009). Mild cognitive impairment: Ten years later. Archives of Neurology, 66(12), 1447 1455. doi:10.1001/archneurol.2009.266 Petersen, R.C., Smith, G.E., Waring, S.C., Ivnik, R.J., Kokmen, E., & Tangelos, E.G. (1997). Aging, memory, and mild cognitive impairment. International Psychogeriatrics, 9, 965 969. Petersen, R.C., Smith, G.E., Waring, S.C., Ivnik, R.J., Tangalos, E.G., & Kokmen, E. (1999). Mild cognitive impairment: Clinical characterization and outcome. Archives of Neurology, 56(3), 303 308. doi:10.1001/archneur.56.3.303 Portet, F., Ousset, P.J., Visser, P.J., Frisoni, G.B., Nobili, F., Scheltens, P., . . . Touchon, J. (2006). Mild cognitive
impairment (MCI) in medical practice: A critical review of the concept and new diagnostic procedure. Report of the MCI Working Group of the European Consortium on Alzheimer’s Disease. Journal of Neurology, Neurosurgery & Psychiatry, 77(6), 714 718. doi:10.1136/ jnnp.2005.085332 Reinvang, I., Grambaite, R., & Espeseth, T. (2012). Executive dysfunction in MCI: Subtype or early symptom. International Journal of Alzheimer’s Disease, 2012, 936272. doi:10.1155/2012/936272 Reisberg, B., Ferris, S.H., de Leon, M.J., & Crook, T. (1988). Global Deterioration Scale (GDS). Psychopharmacology Bulletin, 24(4), 661 663. Rosenberg, P.B., Mielke, M.M., Appleby, B., Oh, E., Leoutsakos, J.M., & Lyketsos, C.G. (2011). Neuropsychiatric symptoms in MCI subtypes: The importance of executive dysfunction. International Journal of Geriatric Psychiatry, 26(4), 364 372. doi:10.1002/gps.2535. Rosenblatt, A., Samus, Q.M., Steele, C.D., Baker, A.S., Harper, M.G., Brandt, J., . . . Lyketsos, C.G. (2004). The Maryland assisted living study: Prevalence, recognition, and treatment of dementia and other psychiatric disorder in the assisted living population of central Maryland. Journal of the American Geriatrics Society, 52(10), 1618 1625. Sheikh, J.I., & Yesavage, J.A. (1986). Geriatric Depression Scale (GDS): Recent evidence and development of a shorter version. Clinical Gerontology, 5, 165 173. doi:10.3109/ 09638288.2010.503835 Smalbrugge, M., Pot, A.M., Jongenelis, K., Beekman, A.T., & Eefsting, J.A. (2005). Prevalence and correlates of anxiety among nursing home patients. Journal of Affect Disorders, 88(2), 145 153. Spitzer, R.L., Kroenke, K., Williams, J.B., & L€ owe, B. (2006). A brief measure for assessing generalized anxiety disorder: The GAD-7. Archives of Internal Medicine, 166(10), 1092 1097. Ward, A., Arrighi, H.M., Michels, S., & Cedarbaum, J.M. (2012). Mild cognitive impairment: Disparity of incidence and prevalence rates. Alzheimer’s & Dementia: The Journal of the Alzheimer’s Association, 8(1), 14 21. doi: 10.1016/j. jalz.2011.01.002 Wild, B., Eckl, A., Herzog, W., Niehoff, D., Lechner, S., Maatouk, I., . . . L€ owe B. (2013). Assessing generalized anxiety disorder in elderly people using the GAD-7 and GAD-2 scales: Results of a validation study. American Journal of Geriatric Psychiatry, 22(10), 1029 1038. doi:10.1016/j. jagp.2013.01.076 Winblad, B., Palmer, K., Kivipelto, M., Jelic, V., Fratiglioni, L., Wahlund, L.O., . . . Petersen, R.C. (2004). Mild cognitive impairment—beyond controversies, towards a consensus: Report of the International Working Group on Mild Cognitive Impairment. Journal of Internal Medicine, 256(3), 240 246. Yaffe, K., Petersen, R.C., Lindquist, K., Kramer, J., & Miller B. (2006). Subtype of mild cognitive impairment and progression to dementia and death. Dementia and Geriatric Cognitive Disorders, 22(4), 312 319.
