This article was downloaded by: [McMaster University] On: 09 January 2015, At: 07:59 Publisher: Routledge Informa Ltd Registered in England and Wales Registered Number: 1072954 Registered office: Mortimer House, 37-41 Mortimer Street, London W1T 3JH, UK
Journal of Clinical and Experimental Neuropsychology Publication details, including instructions for authors and subscription information: http://www.tandfonline.com/loi/ncen19
Visuospatial ability in cortical dementia a
Lawrence Freedman & Lawrie E. Dexter
a
a
The Mississauga Hospital , Published online: 04 Jan 2008.
To cite this article: Lawrence Freedman & Lawrie E. Dexter (1991) Visuospatial ability in cortical dementia, Journal of Clinical and Experimental Neuropsychology, 13:5, 677-690, DOI: 10.1080/01688639108401082 To link to this article: http://dx.doi.org/10.1080/01688639108401082
PLEASE SCROLL DOWN FOR ARTICLE Taylor & Francis makes every effort to ensure the accuracy of all the information (the “Content”) contained in the publications on our platform. However, Taylor & Francis, our agents, and our licensors make no representations or warranties whatsoever as to the accuracy, completeness, or suitability for any purpose of the Content. Any opinions and views expressed in this publication are the opinions and views of the authors, and are not the views of or endorsed by Taylor & Francis. The accuracy of the Content should not be relied upon and should be independently verified with primary sources of information. Taylor and Francis shall not be liable for any losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoever or howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use of the Content. This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sublicensing, systematic supply, or distribution in any form to anyone is expressly forbidden. Terms & Conditions of access and use can be found at http:// www.tandfonline.com/page/terms-and-conditions
Journal of Clinical and Experimental Neuropsychology 1991, Vol. 13, NO. 5, pp. 677-690
0 168-8634/91/1305-0677$3 .Do 0 Swets & Zeitlinger
Visuospatial Ability in Cortical Dementia* Lawrence Freedman and Lawrie E. Dexter The Mississauga Hospital
Downloaded by [McMaster University] at 07:59 09 January 2015
ABSTRACT The level and pattern of visuospatial ability were comparatively examined in patients with putative cortical dementia (CD) and acute right hemisphere (RH)injury. Visuospatial ability was evaluated using measures of block construction, spatial reasoning, hemispatial search, and visuoconstructive copy. The incidence of neglect was also determined using special index measures derived from the spatial tasks. There was no difference between the CD and RII groups on measures of block construction, visuoconstructive copy, and spatial reasoning. While the overall incidence and severity of neglect was generally equivalent between the two clinical groups, 50% of the CD patients exhibited a pattern of right spatial neglect. In addition, a strong relationship was not evident between neglect laterality in CD and corresponding asymmetric cognitive and sensory-perceptual compromise, suggesting that neglect in CD may be due to different mechanisms than those causing neglect following right hemisphere injury. The findings indicate that while patients with putative CD perform like individuals with recent right hemisphere injury with respect to mean level of visuospatial ability, many exhibit a differential pattern of compromise related to the laterality of visuospatial neglect. The relevance of these results for the clinical diagnosis of CD is discussed.
Visuospatial impairment is a prominent clinical feature i n most varieties of cortical dementia (Cummings & Benson, 1983) and is almost invariably present following structural damage t o the right cerebral hemisphere d u e t o stroke and other nondementing neurologic disorders (Kertesz, 1983;Kertesz & Dombrowolski, 1981). In cortical dementia of the Alzheimer’s type (AD), visuospatial compromise has been attributed to pathologic involvement of the right parietal region, and this relationship is supported b y findings o f lateral asymmetries i n cerebral metabolic function in A D patients presenting with disproportionate deficits on spatial and constructional tasks (Chase e t al., 1984; Foster e t al., 1983; Martin,
1987).
* Portions of this paper were presented at the annual meeting of the Canadian Psychological Association, Ottawa, Canada, May, 1990. Address for reprints: Lawrence Freedman, PhD, Department of Psychology, The Mississauga Hospital, 100 Queensway West, Mississauga, Ontario, Canada L5B 1B8. Accepted for publication: November 13, 1YYO.
Downloaded by [McMaster University] at 07:59 09 January 2015
678
LAWRENCE FREEDMAN AND LAWRIE E. DEXTER
Despite sharing a common anatomical basis for visuospatial compromise, there are no studies to our knowledge that have compared the level and pattern of visuospatial ability in cortical dementia (CD) to that found subsequent to acute right hemisphere damage. Such a comparison can be of importance both clinically and theoretically, such as in clarifying the diagnostic criteria for specific CD subtypes and elucidating the possible mechanisms underlying visuospatial impairment in CD. Visuospatial ability was therefore examined in a group of patients with clinicallydiagnosed CD and compared to a sample of patients who had relatively acute right hemisphere damage primarily due to stroke. Visuospatial function was assessed using standardized clinical measures of block construction, visuoconstructive copy, spatial reasoning, and visual search. In addition, since visuospatial neglect is a common Occurrence following right hemisphere damage (Mesulam, 1981). the presence, incidence, and laterality of neglect was determined for both clinical groups using special index scores derived from the visuospatial measures.
METHOD Subjects Three groups composed of 14 subjects each were studied. The groups consisted of patients with cortical dementia (CD). right hemisphere injury (RH). and intact neurobehavioral function (NC). The mean age and educational level of the CD. RH, and NC groups were 64.07,63.07.and 56.7 years, and 11.0, 10.79, and 13 years. respectively. Univariate ANOVA's on the age and education factors revealed no significant differences between the three groups (all p's > .05). In the RH group, 13 (93%) of the subjects sustained ischemic strokes verified by computed tomography (0. The remaining subject had a parietal-occipitalglioblastoma multiforme. Nine (69%) of the 13 vascular lesions occurred in the middle cerebral artery distribution whereas 4 patients had infarcts confied to the posterior cerebral artery. The lobar distribution of the right hemisphere lesions was confiied to the cortical and/or underlying white matter regions of the parietal ( n = 4), frontal ( n = 3). parietal-occipital( n = 3), frontoparietal (n = 1). and occipital ( n = 2) lobes. The remaining case sustained an intracerebral haemorrhage confined to the posterior limb of the internal capsule with ipsilateral extension to the basal ganglia. Ten (77%) of the 13 vascular patients had acute (< 1 month) lesions at the time of testing whereas the remaining three had relatively static infarcts. Three (21%) patients in the RH group had a left homonymous hemianopsia. Twelve (86%) CD patients had probable AD based on NJNCDS/ADRDA criteria (McKhann et al.. 1984).Of the remaining two patients, one had probable Pick's disease and the other had a posterior cortical dementia (Benson, Davis, & Synder. 1988). All CD subjects had routine CT, and none showed evidence of focal lesions or hydrocephalus. The normal control group was comprised of individuals living in the community who were referred for neuropsychological testing by a neurologist for suspected cerebral dysfunction. Specifically, nine of the controls were referred for dementia evaluation while the remaining five were seen in consultation to determine the presence or absence of brain damage. In our setting, all patients referred to the neuropsychologyservice receive routine neurological and CT examinations. For the present study, all controls had normal neurological, neuropsychological, and CT evaluations.
DEMENTIA AND SPATIAL ABILITY
679
Downloaded by [McMaster University] at 07:59 09 January 2015
Measures Four tests of visuospatial ability were administered to all subjects as part of a formal neuropsychological examination. These included the WAIS-R Block Design subtest (BD) (Wechsler, 1981), Raven Coloured Progressive Matrices (RCM) (Raven, 1965). ReyOsterrieth Figure copy (RO) (Lezak, 1983), and a modified version of Kimura’s (1984) visual search (VS) test. Raw scores were utilized in all data analyses, except for visual search in which median hemispatial search times were employed.
Visual Neglect Scoring Criteria for determining visual neglect was employed for three of the visuospatial measures (RCM, RO, and VS). A bias score was computed for the RCM that was derived from a previous study (Costa, Vaughan, Horwitz, & Ritter, 1969) showing that normals had a probability of a position preference score (Left - Right) o f f 7 that was less than 2% (1/ 63). For the present study, a cut-off position preference score of f 6 was utilized. For the RO copy, a scoring system was devised to determine lateral neglect. In this system, the RO model was divided in half vertically creating a right and left side. A five-point system was used based upon placement of items within or outside each hemispace and as to whether items were distorted, placed poorly, or absent. Each half figure was assessed equal point totals based on a perfect copy (55). The difference between the two lateral scores (left half minus right half) was calculated to arrive at an index score. A difference score of f 6 was selected in defining neglect based on a comparative analysis to an independent sample (n = 10) of neurologically-intact, clinically referred patients. The VS task was modified in two ways. First, median hemispatial search times were utilized since clinical experience with this test had consistently revealed marked variability in items search times when mean scores were used. The second modification changed the maximum alloted default search time from 60 to 120 s. Items not located in the left or right hemispace were given a search time of 120 s. An index score of lateral neglect was determined using the difference between the median search times for the left and right hemispace. A cut-off score o f f 4 s was selected for this measure. Accuracy scores in VS were not statistically analyzed due to a general ceiling effect for this parameter in all groups. RESULTS Table 1 presents the mean scores for each group on the visuospatial measures. Univariate ANOVA’s were performed on scores from three tests of visuospatial ability (RCM, BD, RO) across all groups. Analyses revealed a significant effect across three of the measures, F(RCM) (2,39) = 22.5, p < .OO;F(BD) (2,39) = 29.6, p < .OO;F ( R 0 ) (2.39) = 12.9, p < .OO.Separate post-hoc analyses using the multiple range test showed that on all measures, the NC group differed significantly from the CD and R H groups @ < .05 for all comparisons). There were no statistically significant differences between the CD and RH groups on RCM, RO, and BD. A 2 X 2 mixed ANOVA was performed on the visual search latency times for the CD and RH groups with left and right hemispace as the repeated factor. There was no main effect for group, F c 1, or hemispace, F(1,26) = 2.20, p > .14. The < .07. group X hemispace interaction approached significance, F(1,26) = 3 . 5 4 , ~ Inspection of Figure 1 reveals that the near-significance of the interaction was due to longer left hemispatial search times received by the R H group.
680
LAWRENCE FREEDMAN AND LAWRIE E. DEXTER
Table 1. Means (raw scores), Standard Deviations, and Ranges for the CD, RH, and NC groups on selected visuospatial measures. Group Measure
RCM
Downloaded by [McMaster University] at 07:59 09 January 2015
RO BD
VS-Right VS-Left
CD
NC
RH
M
SD
M
SD
M
18.1 (8-30) 20.5 (4-32) 6.3 (0-21) 9.42 (3-38) 8.21 (2-32)
5.5
20 (9-31) 19.7 (6-33) 10.4 (0-21) 5.35 (2-13) 15.6 (2-77)
6.6
31 3.78 (23-36) 32.7 3.5 (25-36) 10 28 (12-47) 4.14 2.14 (2-10) 3.71 1.4 (2-7)
8.9 6.3 9.5 8.1
9.0 7.0 3.05 20.1
SD
CD = Cortical dementia; RH=Right hemisphere; NC = Normal controls; RCM = Raven Coloured Matrices; RO = Rey Osterrieth; BD = Block Design; VS Right = Visual Search, Right hemispace; VS Left = Visual Search, Left hemispace. Ranges in parentheses.
cj
0)
20 19 18
17 l6
v)
15
Q)
l4 l3 12 '1
Y
E i= c g
10
( P 9
$
8
s 7
( P 6
a 5
-
Left HemispaceiRight Hemispace Right Hemisphere Cortical Dementia
Fig. 1. Median hemispatial search latencies for the CD and RH groups on visual search.
681
DEMENTIA AND SPATIAL. ABILITY
Table 2. Mean scores, Standard deviations, and ranges for the CD, RH, and NC groups on the Rey-Osterrieth neglect index Group
Downloaded by [McMaster University] at 07:59 09 January 2015
Rey Score
CD
RH
NC
M
SD
M
SD
Right Hemispace
39.9
15.5
37
Left Hemispace
(2-54) 41.1 10.5 (17-55)
M
SD
12.9
51.8
5.8
15.7
(34-55) 51.7 3.6 (43-55)
(10-55)
29.8 (1-54)
Ranges in parentheses. Maximum score = 55
Table 2 presents the mean scores for the CD and RH groups on the ReyOsterrieth neglect index while Figure 2 graphically plots these scores. A mixed 2 X 2 ANOVA was performed with group (CD & RH) as the between-factor and hemispatial score (left & right) as the repeated factor. There was no main effect for group, F(1,26) = 2.21, p >.14, or hemispace, F(1,26) = 1.97, p >.17. The interaction between group and hemispace approached significance, F(1.26) = 3.71, p .05; XCD = 7.33 (SD = .81), XRH = 11.8 (SD = 8.28)), VS (U = 11.5, p > .05; RCD = 14.9 (SD = 9.39), XRH = 24.6 (SD = 24.9)), and RO (U = 34, p > .05; XCD = 14.7 (SD= 10.1), XRH = 13.0 (SD = 6.56)).
Laterality of Neglect
Downloaded by [McMaster University] at 07:59 09 January 2015
As expected, all RH subjects with subclinical, moderate, and moderately severe
neglect had it confined exclusively to the left side. In contrast, 7 CD subjects had index scores compatible with neglect confined to the right hemispace whereas 6 had left hemispatial neglect (the total of 13 CD patients is attributable to the finding that two CD patients had evidence of bilateral neglect and were thus treated as separate data points for this analysis). Figure 4 shows an example of right neglect on the RO copy in a patient diagnosed with probable AD. The proportional difference of left and right neglect among the RH and CD groups was statistically significant, x2 (2, N = 28) = 13.36, p
Journal of Clinical and Experimental Neuropsychology Publication details, including instructions for authors and subscription information: http://www.tandfonline.com/loi/ncen19
Visuospatial ability in cortical dementia a
Lawrence Freedman & Lawrie E. Dexter
a
a
The Mississauga Hospital , Published online: 04 Jan 2008.
To cite this article: Lawrence Freedman & Lawrie E. Dexter (1991) Visuospatial ability in cortical dementia, Journal of Clinical and Experimental Neuropsychology, 13:5, 677-690, DOI: 10.1080/01688639108401082 To link to this article: http://dx.doi.org/10.1080/01688639108401082
PLEASE SCROLL DOWN FOR ARTICLE Taylor & Francis makes every effort to ensure the accuracy of all the information (the “Content”) contained in the publications on our platform. However, Taylor & Francis, our agents, and our licensors make no representations or warranties whatsoever as to the accuracy, completeness, or suitability for any purpose of the Content. Any opinions and views expressed in this publication are the opinions and views of the authors, and are not the views of or endorsed by Taylor & Francis. The accuracy of the Content should not be relied upon and should be independently verified with primary sources of information. Taylor and Francis shall not be liable for any losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoever or howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use of the Content. This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sublicensing, systematic supply, or distribution in any form to anyone is expressly forbidden. Terms & Conditions of access and use can be found at http:// www.tandfonline.com/page/terms-and-conditions
Journal of Clinical and Experimental Neuropsychology 1991, Vol. 13, NO. 5, pp. 677-690
0 168-8634/91/1305-0677$3 .Do 0 Swets & Zeitlinger
Visuospatial Ability in Cortical Dementia* Lawrence Freedman and Lawrie E. Dexter The Mississauga Hospital
Downloaded by [McMaster University] at 07:59 09 January 2015
ABSTRACT The level and pattern of visuospatial ability were comparatively examined in patients with putative cortical dementia (CD) and acute right hemisphere (RH)injury. Visuospatial ability was evaluated using measures of block construction, spatial reasoning, hemispatial search, and visuoconstructive copy. The incidence of neglect was also determined using special index measures derived from the spatial tasks. There was no difference between the CD and RII groups on measures of block construction, visuoconstructive copy, and spatial reasoning. While the overall incidence and severity of neglect was generally equivalent between the two clinical groups, 50% of the CD patients exhibited a pattern of right spatial neglect. In addition, a strong relationship was not evident between neglect laterality in CD and corresponding asymmetric cognitive and sensory-perceptual compromise, suggesting that neglect in CD may be due to different mechanisms than those causing neglect following right hemisphere injury. The findings indicate that while patients with putative CD perform like individuals with recent right hemisphere injury with respect to mean level of visuospatial ability, many exhibit a differential pattern of compromise related to the laterality of visuospatial neglect. The relevance of these results for the clinical diagnosis of CD is discussed.
Visuospatial impairment is a prominent clinical feature i n most varieties of cortical dementia (Cummings & Benson, 1983) and is almost invariably present following structural damage t o the right cerebral hemisphere d u e t o stroke and other nondementing neurologic disorders (Kertesz, 1983;Kertesz & Dombrowolski, 1981). In cortical dementia of the Alzheimer’s type (AD), visuospatial compromise has been attributed to pathologic involvement of the right parietal region, and this relationship is supported b y findings o f lateral asymmetries i n cerebral metabolic function in A D patients presenting with disproportionate deficits on spatial and constructional tasks (Chase e t al., 1984; Foster e t al., 1983; Martin,
1987).
* Portions of this paper were presented at the annual meeting of the Canadian Psychological Association, Ottawa, Canada, May, 1990. Address for reprints: Lawrence Freedman, PhD, Department of Psychology, The Mississauga Hospital, 100 Queensway West, Mississauga, Ontario, Canada L5B 1B8. Accepted for publication: November 13, 1YYO.
Downloaded by [McMaster University] at 07:59 09 January 2015
678
LAWRENCE FREEDMAN AND LAWRIE E. DEXTER
Despite sharing a common anatomical basis for visuospatial compromise, there are no studies to our knowledge that have compared the level and pattern of visuospatial ability in cortical dementia (CD) to that found subsequent to acute right hemisphere damage. Such a comparison can be of importance both clinically and theoretically, such as in clarifying the diagnostic criteria for specific CD subtypes and elucidating the possible mechanisms underlying visuospatial impairment in CD. Visuospatial ability was therefore examined in a group of patients with clinicallydiagnosed CD and compared to a sample of patients who had relatively acute right hemisphere damage primarily due to stroke. Visuospatial function was assessed using standardized clinical measures of block construction, visuoconstructive copy, spatial reasoning, and visual search. In addition, since visuospatial neglect is a common Occurrence following right hemisphere damage (Mesulam, 1981). the presence, incidence, and laterality of neglect was determined for both clinical groups using special index scores derived from the visuospatial measures.
METHOD Subjects Three groups composed of 14 subjects each were studied. The groups consisted of patients with cortical dementia (CD). right hemisphere injury (RH). and intact neurobehavioral function (NC). The mean age and educational level of the CD. RH, and NC groups were 64.07,63.07.and 56.7 years, and 11.0, 10.79, and 13 years. respectively. Univariate ANOVA's on the age and education factors revealed no significant differences between the three groups (all p's > .05). In the RH group, 13 (93%) of the subjects sustained ischemic strokes verified by computed tomography (0. The remaining subject had a parietal-occipitalglioblastoma multiforme. Nine (69%) of the 13 vascular lesions occurred in the middle cerebral artery distribution whereas 4 patients had infarcts confied to the posterior cerebral artery. The lobar distribution of the right hemisphere lesions was confiied to the cortical and/or underlying white matter regions of the parietal ( n = 4), frontal ( n = 3). parietal-occipital( n = 3), frontoparietal (n = 1). and occipital ( n = 2) lobes. The remaining case sustained an intracerebral haemorrhage confined to the posterior limb of the internal capsule with ipsilateral extension to the basal ganglia. Ten (77%) of the 13 vascular patients had acute (< 1 month) lesions at the time of testing whereas the remaining three had relatively static infarcts. Three (21%) patients in the RH group had a left homonymous hemianopsia. Twelve (86%) CD patients had probable AD based on NJNCDS/ADRDA criteria (McKhann et al.. 1984).Of the remaining two patients, one had probable Pick's disease and the other had a posterior cortical dementia (Benson, Davis, & Synder. 1988). All CD subjects had routine CT, and none showed evidence of focal lesions or hydrocephalus. The normal control group was comprised of individuals living in the community who were referred for neuropsychological testing by a neurologist for suspected cerebral dysfunction. Specifically, nine of the controls were referred for dementia evaluation while the remaining five were seen in consultation to determine the presence or absence of brain damage. In our setting, all patients referred to the neuropsychologyservice receive routine neurological and CT examinations. For the present study, all controls had normal neurological, neuropsychological, and CT evaluations.
DEMENTIA AND SPATIAL ABILITY
679
Downloaded by [McMaster University] at 07:59 09 January 2015
Measures Four tests of visuospatial ability were administered to all subjects as part of a formal neuropsychological examination. These included the WAIS-R Block Design subtest (BD) (Wechsler, 1981), Raven Coloured Progressive Matrices (RCM) (Raven, 1965). ReyOsterrieth Figure copy (RO) (Lezak, 1983), and a modified version of Kimura’s (1984) visual search (VS) test. Raw scores were utilized in all data analyses, except for visual search in which median hemispatial search times were employed.
Visual Neglect Scoring Criteria for determining visual neglect was employed for three of the visuospatial measures (RCM, RO, and VS). A bias score was computed for the RCM that was derived from a previous study (Costa, Vaughan, Horwitz, & Ritter, 1969) showing that normals had a probability of a position preference score (Left - Right) o f f 7 that was less than 2% (1/ 63). For the present study, a cut-off position preference score of f 6 was utilized. For the RO copy, a scoring system was devised to determine lateral neglect. In this system, the RO model was divided in half vertically creating a right and left side. A five-point system was used based upon placement of items within or outside each hemispace and as to whether items were distorted, placed poorly, or absent. Each half figure was assessed equal point totals based on a perfect copy (55). The difference between the two lateral scores (left half minus right half) was calculated to arrive at an index score. A difference score of f 6 was selected in defining neglect based on a comparative analysis to an independent sample (n = 10) of neurologically-intact, clinically referred patients. The VS task was modified in two ways. First, median hemispatial search times were utilized since clinical experience with this test had consistently revealed marked variability in items search times when mean scores were used. The second modification changed the maximum alloted default search time from 60 to 120 s. Items not located in the left or right hemispace were given a search time of 120 s. An index score of lateral neglect was determined using the difference between the median search times for the left and right hemispace. A cut-off score o f f 4 s was selected for this measure. Accuracy scores in VS were not statistically analyzed due to a general ceiling effect for this parameter in all groups. RESULTS Table 1 presents the mean scores for each group on the visuospatial measures. Univariate ANOVA’s were performed on scores from three tests of visuospatial ability (RCM, BD, RO) across all groups. Analyses revealed a significant effect across three of the measures, F(RCM) (2,39) = 22.5, p < .OO;F(BD) (2,39) = 29.6, p < .OO;F ( R 0 ) (2.39) = 12.9, p < .OO.Separate post-hoc analyses using the multiple range test showed that on all measures, the NC group differed significantly from the CD and R H groups @ < .05 for all comparisons). There were no statistically significant differences between the CD and RH groups on RCM, RO, and BD. A 2 X 2 mixed ANOVA was performed on the visual search latency times for the CD and RH groups with left and right hemispace as the repeated factor. There was no main effect for group, F c 1, or hemispace, F(1,26) = 2.20, p > .14. The < .07. group X hemispace interaction approached significance, F(1,26) = 3 . 5 4 , ~ Inspection of Figure 1 reveals that the near-significance of the interaction was due to longer left hemispatial search times received by the R H group.
680
LAWRENCE FREEDMAN AND LAWRIE E. DEXTER
Table 1. Means (raw scores), Standard Deviations, and Ranges for the CD, RH, and NC groups on selected visuospatial measures. Group Measure
RCM
Downloaded by [McMaster University] at 07:59 09 January 2015
RO BD
VS-Right VS-Left
CD
NC
RH
M
SD
M
SD
M
18.1 (8-30) 20.5 (4-32) 6.3 (0-21) 9.42 (3-38) 8.21 (2-32)
5.5
20 (9-31) 19.7 (6-33) 10.4 (0-21) 5.35 (2-13) 15.6 (2-77)
6.6
31 3.78 (23-36) 32.7 3.5 (25-36) 10 28 (12-47) 4.14 2.14 (2-10) 3.71 1.4 (2-7)
8.9 6.3 9.5 8.1
9.0 7.0 3.05 20.1
SD
CD = Cortical dementia; RH=Right hemisphere; NC = Normal controls; RCM = Raven Coloured Matrices; RO = Rey Osterrieth; BD = Block Design; VS Right = Visual Search, Right hemispace; VS Left = Visual Search, Left hemispace. Ranges in parentheses.
cj
0)
20 19 18
17 l6
v)
15
Q)
l4 l3 12 '1
Y
E i= c g
10
( P 9
$
8
s 7
( P 6
a 5
-
Left HemispaceiRight Hemispace Right Hemisphere Cortical Dementia
Fig. 1. Median hemispatial search latencies for the CD and RH groups on visual search.
681
DEMENTIA AND SPATIAL. ABILITY
Table 2. Mean scores, Standard deviations, and ranges for the CD, RH, and NC groups on the Rey-Osterrieth neglect index Group
Downloaded by [McMaster University] at 07:59 09 January 2015
Rey Score
CD
RH
NC
M
SD
M
SD
Right Hemispace
39.9
15.5
37
Left Hemispace
(2-54) 41.1 10.5 (17-55)
M
SD
12.9
51.8
5.8
15.7
(34-55) 51.7 3.6 (43-55)
(10-55)
29.8 (1-54)
Ranges in parentheses. Maximum score = 55
Table 2 presents the mean scores for the CD and RH groups on the ReyOsterrieth neglect index while Figure 2 graphically plots these scores. A mixed 2 X 2 ANOVA was performed with group (CD & RH) as the between-factor and hemispatial score (left & right) as the repeated factor. There was no main effect for group, F(1,26) = 2.21, p >.14, or hemispace, F(1,26) = 1.97, p >.17. The interaction between group and hemispace approached significance, F(1.26) = 3.71, p .05; XCD = 7.33 (SD = .81), XRH = 11.8 (SD = 8.28)), VS (U = 11.5, p > .05; RCD = 14.9 (SD = 9.39), XRH = 24.6 (SD = 24.9)), and RO (U = 34, p > .05; XCD = 14.7 (SD= 10.1), XRH = 13.0 (SD = 6.56)).
Laterality of Neglect
Downloaded by [McMaster University] at 07:59 09 January 2015
As expected, all RH subjects with subclinical, moderate, and moderately severe
neglect had it confined exclusively to the left side. In contrast, 7 CD subjects had index scores compatible with neglect confined to the right hemispace whereas 6 had left hemispatial neglect (the total of 13 CD patients is attributable to the finding that two CD patients had evidence of bilateral neglect and were thus treated as separate data points for this analysis). Figure 4 shows an example of right neglect on the RO copy in a patient diagnosed with probable AD. The proportional difference of left and right neglect among the RH and CD groups was statistically significant, x2 (2, N = 28) = 13.36, p
