Original research paper
Cochlear implantation and alcohol misuse Lyndsay Fraser, Mary Shanks, Peter Wardrop, Agnes Allen Scottish Cochlear Implant Service, Crosshouse Hospital, Kilmarnock, UK Objective: To assess the outcome of patients referred to our national centre for cochlear implantation who have a history of alcohol misuse. Methods: A retrospective case-note review from 1989 – current was performed. Information was collected on aetiology/duration of deafness, current alcohol habits, and co-morbidities. For those implanted, we assessed implant type, anaesthetic, and complications. Our team rated each patients’ engagement with the rehabilitation programme and collected 9-month post-implant Bamford–Kowal–Bench (BKB) and 1-year post-implant categories of auditory performance (CAP) scores. Results: Fourteen patients with a history of harmful drinking or alcohol dependency were identified. Aetiology of deafness was varied but most commonly included sensorineural hearing loss of unknown aetiology (7), neomycin ototoxicity (3), and head injury (2). Twelve were suitable for implantation and 11 have been successfully implanted. Three patients experienced a post-operative complication (one major/two minor). Most (eight) were rated as having good engagement with the rehabilitation process and three rated as average. Nine-month post-implant BKB scores ranged from 10 to 92 (mean 56). One-year post-implant CAP scores range from 4 to 8. Conclusion: Patients with a background of alcohol misuse are being increasingly referred to our service. Alcohol is often implicated in the aetiology of deafness or can be sequelae of the psychological issues sometimes experienced by deaf patients. Even in the case of active alcohol misuse at the time of implantation, all surviving patients are currently active users and our results show that these patients can do well following implantation with the right support. Keywords: Cochlear implant, Alcohol, Outcomes
Introduction Cochlear implants have revolutionized the management of patients with severe to profound hearing loss over the past 30 years. Improving technology and outcomes has led to an expansion of the selection criteria for potentially suitable candidates. At our national centre for cochlear implantation, we have observed a steady increase in the number of patients with a history of alcohol problems being referred to us in recent years. Scotland is known to have high levels of alcohol misuse compared to the rest of the UK, with an estimated 4.9% of the population aged over 16 dependent on alcohol (Audit Scotland, 2009). Scotland has one of the highest rates of alcohol-related harm in Western Europe (Whyte and Ajetunmobi, 2012) and in 2010 alcohol-related deaths were double those found in England and Wales (Beeston et al., 2012). Assessment of suitability for implantation can be
Correspondence to: Lyndsay Fraser, Scottish Cochlear Implant Service, Crosshouse Hospital, Kilmarnock KA2 0BE, UK. Email: [email protected]
© W. S. Maney & Son Ltd 2015 DOI 10.1179/1754762814Y.0000000089
difficult in such patients for a variety of reasons and outcomes in this patient group have not yet been described in the literature. We describe our experience of 14 patients with a background of alcohol excess referred for cochlear implant assessment.
Study design Retrospective case series.
Methods Patients with either current or previous excessive alcohol consumption, as documented in their original referral correspondence, were identified from our departmental database from 1989 – current. According to ICD-10, problems with alcohol can be classified into two main categories; ‘harmful drinking’ is defined as a pattern of drinking that causes damage to physical or mental health while ‘alcohol dependence’ is defined as a cluster of physiological, behavioural, and cognitive phenomena in which the use of alcohol takes on a much higher priority for an individual than other behaviours that previously had greater
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value (World Health Organization, 1992). We included patients with either diagnosis. Casenotes and programming data were retrospectively reviewed. We collected information on age, sex, aetiology and duration of deafness, current reported alcohol intake, and co-morbidities. For those found suitable for implantation, we collected data on type of implant, anaesthetic grading/type of anaesthesia, and complications. We asked our cochlear implant team to rate each patients’ engagement with the rehabilitation programme as either poor, average, or good and collected 9-month post-implant Bamford–Kowal–Bench (BKB) scores and 1-year post-implant categories of auditory performance (CAP) scores. The BKB sentence test (Bench et al., 1979) is a popular open-set speech perception test developed for use with children and adults. The test can be administered in quiet conditions or in the presence of background noise and is scored depending on the number of correct words correctly identified. The mean BKB sentence score for adult cochlear implant users within our unit is 59%. CAP is a non-linear hierarchical scale which is used to measure the development of speech recognition ability and functional hearing. Although originally designed for use in hearing impaired children (Archbold et al., 1995) with seven categories, the scale has been modified over the years to include additional items that address the more complex listening skills achievable with a cochlear implant and can be applied to adults also. Over the period of our review, our patients were assessed with the eight category CAP scale used by Summerfield and team in their national review of UK cochlear implantation Table 1
CAP score 1 2 3
4
5 6 7 8
52
Categories of auditory performance % of implant patients achieving CAP level in our unit
Description Can detect environmental sounds Can identify at least five environmental sounds Understanding of common phrases is enhanced with cochlear implant (and lip-reading) Understanding of conversation is enhanced with cochlear implant (and lip-reading) Can understand common phrases without lip-reading Can understand conversation without lip-reading Can use telephone with a familiar talker Can use the telephone with an unfamiliar talker
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(Summerfield and Marshall, 1995) (Table 1). In this report, it was recommended that the majority of adult patients should achieve at least the first five abilities within 12 months of implantation. To allow for interpretation of the CAP scores from our series, Table 1 also demonstrates the percentage of our total implant population that achieves each of the abilities within the first 12 months after implantation.
Results From 1989 to present, 14 patients (8 female, 6 male) with a history of either harmful drinking or alcohol dependency were referred for cochlear implant assessment. Eleven of these patients have been referred within the past 5 years. The mean age was 56 (range 32–72). Aetiology of deafness was varied: seven sensorineural hearing loss (SNHL) of unknown aetiology (six sudden, one progressive), three neomycin ototoxicity after treatment for hepatic encephalopathy, two head injuries, one childhood mumps, and one patient with previous chemical labyrinthectomy for unilateral Meniere’s disease followed by sudden onset SNHL in the contralateral ear. Mean duration of deafness in the better hearing ear was 2 years and 7 months (range 6 months to 13 years). Of the 14 patients referred, 1 died before initial clinic review and 1 is currently undergoing assessment. Twelve have been found suitable for implantation and 11 have been successfully implanted. Our unit is currently supporting 703 adult patients implanted since 1989, so this patient group therefore makes up 1.7% of our implant population. One patient died of complications of alcohol abuse before implantation could be performed. Table 2 displays the demographics of the implanted patients including current alcohol habits at the time of surgery. Most patients had a fairly extensive past medical history with 7 out of 11 having established alcoholic liver disease. The average American Society of Anaesthesiology grading was 3, equating to severe systemic disease. Despite this, all but one was found suitable for general anaesthesia. Patient 9 was deemed too unfit for general anaesthesia but was motivated to proceed with surgery under local anaesthetic. Choice of device is usually left to the patient within our unit; seven chose Nucleus devices (one Nucleus mini-system 22, one Nucleus C124M, three Nucleus CI24RE, one Nucleus CI512, and one Nucleus CI422) and four chose Medel (Medel MI1000). Most patients (eight) were rated as having good engagement with the post-implantation rehabilitation process. Three were rated as average and none as poor. All patients that had pre-operative BKB scores recorded (9 of 11) scored 0%. Nine-month postimplant BKB scores were available for eight patients
Table 2 Patient demographics
Aetiology of deafness
Duration deafness in better hearing ear (years) Abstinent?
Co-morbidities
ASA grade
Complications
Preimplant BKB (%)
9-month BKB (%)
12-month CAP
NR
10
4
Good Good
0 0
66 NR
6 5
Good
0
82
8
Patient engagement
13
No
COPD
3
2 3
Mumps SSNHL
3 1
No 6 months
Polydrug abuse, anxiety/depression Alcoholic liver disease, peripheral neuropathy, psoriasis
1 3
4
0.5
3 months
COPD, hypertension
2
5
Chemical labyrinthectomy for Meniere’s and contralateral SSNHL SSNHL
Peri-operative CSF leak due to low dura. Settled conservatively None Post-operative wound infection requiring explantation at 4 months. Reimplanted at 8 months None
4
5 years
3
None
Good
0
26
6
6
Neomycin ototoxicity
1
3 years
3
None
Average
0
92
6
7
PSNHL
5
10 years
3
None
Good
0
85
8
8
Head injury
1
1 year
3
NR
52
7
SSNHL
1
5 years
3
Post-operative wound infection managed conservatively None
Average
9
Good
0
31
6
1.5
3 years
3
None
Good
0
Awaited
Awaited
1
1 year
Alcoholic liver disease, hypertension, hiatus hernia Alcoholic liver disease, peripheral neuropathy, anxiety/depression Type 2 diabetes, COPD, peripheral neuropathy, left ventricular hypertrophy Alcoholic liver disease, chronic subdural haematoma, hypertension, hypothyroidism Alcoholic liver disease, chronic renal failure, Barrett’s oesophagus, duodenal ulcer, asthma, hypertension, right heart failure Alcoholic liver disease, cerebral atrophy, chronic renal failure Alcoholic liver disease, hypertension, non-healing fracture of ankle
3
None
Good
0
Awaited
Awaited
10 Neomycin ototoxicty 11 SSNHL
Average
2015
SSNHL, sudden onset sensorineural hearing loss of unknown aetiology; PSNHL, progressive sensorineural hearing loss of unknown aetiology; COPD, chronic obstructive pulmonary disease; NR, not recorded; BKB, Bamford–Kowal–Bench test; CAP, categories of auditory performance; ASA, American Society of Anaesthesiology.
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Head injury
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and ranged from 10 to 92 (mean 56). Nine-month BKB scores are awaited in two patients who were recently implanted and are missing for one patient due to difficulty attending appointments due to issues with ill health and transport. One-year postimplant CAP scores are also displayed in Table 2. All patients are currently active users apart from patient 3 who died 5 years post-implantation and patient 7 who died 1 year post-implantation.
Discussion We have noted a sharp increase in the number of patients referred to us with a background of alcohol problems over the past 10 years. This is likely due to a combination of factors and may reflect the general trend of increasing alcohol sales and alcohol-related morbidity within Scottish society (Robinson et al., 2013). In addition, an awareness of widening criteria for cochlear implantation may have led to patients being referred who might previously have been assumed to be poor candidates due to their accompanying co-morbidities or predicted poor engagement with the rehabilitation process. Aetiology of deafness in our cohort was varied, with the most common reason being SNHL of unclear aetiology. Although it is difficult to pinpoint alcohol as the specific cause in these patients due to inconsistent documentation of duration of alcohol misuse within their records, chronic alcohol abuse is known to be associated with an increased risk of hearing loss (Rosenhall et al., 1993; Verma et al., 2006) and no other obvious causes were identified. Alcohol is known to elevate the acoustic reflex threshold, increase temporary threshold shift (Robinette and Brey, 1978), and cause elevation of high-frequency thresholds (Verma et al., 2006). Although alcohol is known to affect those aspects of hearing which require higher levels of central auditory processing (hearing under difficult listening conditions, hearing at lower frequencies, monaural versus binaural hearing, and discrimination of higher frequencies versus lower frequencies), the exact sites of action remain unknown (Pearson et al., 1999). The relationship between low-to-moderate levels of alcohol consumption and hearing remains less clear cut. A protective association has been observed in some studies (Popelka et al., 2000; Fransen et al., 2008) but not in others (Brant et al., 1996). It has been proposed that the cardioprotective effects of moderate alcohol intake, such as higher high-density lipoprotein cholesterol and antithrombotic activity, may translate to a decreased risk of hearing loss by potentially protecting against disturbances in cochlear blood flow (Seidman et al., 1999). Curhan et al. (2010) found that patients who had a lower intake of vitamin B12 coupled with high alcohol consumption had an
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increased risk of hearing loss, suggesting a possible co-factor. Neomycin ototoxicity following treatment for hepatic encephalopathy was the second most common aetiology encountered. Hepatic encephalopathy is a serious and potentially fatal neuropsychiatric complication of both acute and chronic liver disease and neomycin acts by inhibiting mucosal glutaminase in the intestine, which reduces ammonia production in the gut. The drug is associated with several well-established side effects including ototoxicity, nephrotoxicity, and intestinal malabsorption and its use has steadily declined in recent years due to the availability of safer antibiotics such as rifaximin (Prakash and Mullen, 2010). The majority of patients (82%) reported abstinence from alcohol at the time of surgery. We do not routinely monitor blood markers of excessive alcohol consumption (elevated mean red blood cell volume or serum gamma glutamyl transferase) as false positives can occur and self-reported consumption is usually taken as the ‘gold standard’ (Scottish Intercollegiate Guidelines Network, 2003). Excessive alcohol consumption was a factor for two patients at the time of surgery. Although not ideal, we decided to proceed with implantation as each patient was felt to be sufficiently motivated and likely to gain benefit on preimplant assessment. We felt that each patient’s continued alcohol misuse was due to ongoing psychological problems related to their profound hearing loss and that this was likely to be eased by implantation (Mo et al., 2005). Profound hearing loss not only causes substantial impairments in important life domains such as social functioning and capability to perform daily activities, but also significantly impacts on mental health making those affected more vulnerable to depression (Hallam et al., 2006). We do not routinely screen for alcohol misuse or depression when we assess patients but instead rely on diagnostic information in the referral correspondence or information given by the patient. We acknowledge that it is therefore possible that other patients coming through our service have experienced or are currently experiencing problems relating to alcohol, but that their problems have remained subclinical. It is also possible that some patients who were referred and subsequently found to be unsuitable for cochlear implantation could have had a history of alcohol misuse that we have not been aware of. Unfortunately, due to the large number of referrals since 1989 and probable lack of documentation of alcohol issues (particularly in the early days of the programme when fewer were being referred and awareness of the issue was lower), we are unable to quantify this with a figure. No patient has ever been turned down solely on the basis of alcohol misuse. While social factors such as
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homelessness, poor family support, and criminal record are important in this group and would play a part in decision making, none would be completely exclusive. Each issue would need to be reviewed individually in the context of the patient’s audiology, medical history, motivation, and overall likelihood of gaining benefit. Where social factors are an issue, we would aim to support the patient directly by liasing with the correct agencies and have done this with success in the past. If severe co-morbidity is an issue, then this of course has implications for suitability for surgery but again would be assessed on an individual basis, with local anaesthetic remaining an option if general anaesthesia is contraindicated (as in patient 9). Patients with severe social disruption and significant co-morbidity are likely to be unsuitable candidates, but it has been our experience that these patients are not referred on for assessment by peripheral centres from the outset. Three of our implanted patients (27%) in this series experienced a peri- or post-operative complication (one major and two minor), which is slightly higher than average in a UK adult cochlear implant population (Dutt et al., 2005). Wound infection was the commonest issue, which is unsurprising given the increased rate of post-operative infection seen in patients with a history of chronic alcohol abuse (Spies et al., 2004). Peri-operative patient movement was an issue with patient 9 who underwent local anaesthetic implantation and although surgically challenging, implant insertion was performed successfully. Our patient group also posed a particular challenge for our anaesthetic team, as previous or current alcohol excess is known to predispose to intra-operative pulmonary and cardiac dysfunction, metabolic disturbance, and altered pharmacokinetics with common anaesthetic drugs (Adams, 2010). Fortunately, no anaesthetic complications were encountered. One-year post-operative CAP scores improved for all patients and ranged from 4 to 8. Most patients appear to be engaging well with the rehabilitation process. It is however very difficult to ascertain which of our patients continued to misuse alcohol despite cochlear implantation, as this is not formally assessed at programming appointments. However, as a result of a raised awareness of alcohol issues among our patients, we are keen to monitor those with known alcohol issues throughout their implantation journey and have begun to issue a Fast Alcohol Screening Test (Hodgson et al., 2002) and depression questionnaire at each visit to allow us to identify patients who have continued dependency and require additional support. The effects of alcohol on the psychophysical responses during cochlear implant mapping have been investigated by Meerton et al. (2005). The
Cochlear implantation and alcohol misuse
authors showed that alcohol consumption 1 hour before programming significantly increases the upper end of the dynamic range (‘comfort level’) in cochlear implant patients in comparison with placebo. This effect was felt to be likely due to the result of change in the auditory pathways proximal to the cochlea. We have not noticed such an effect during programming sessions, although this may be due to the fact that we have had very few patients attend for programming actively intoxicated. Funding for cochlear implantation in Scotland is provided by central government to offer implantation for all suitable candidates who meet the selection criteria and candidature is determined by the team’s assessment of overall likelihood of gaining benefit. We have not therefore experienced any funding issues with implanting this particular patient group.
Conclusion Patients with a history of alcohol misuse are being increasingly referred to our national cochlear implant service. Outcomes in this patient group have not yet been described. Alcohol misuse is often implicated in the aetiology of deafness, or is sequelae of the psychological issues and social isolation that some profoundly deaf patients experience. Associated comorbidity is often a concern and makes anaesthesia and surgery more fraught, with post-operative infection a particular risk in this patient group. Even in the case of active alcohol misuse at the time of implantation, all surviving patients are currently active users and our results show that these patients can do well following implantation with the right support.
Disclaimer statements Contributors L.F.: Data collection, literature review, manuscript author. P.W.: Study design, manuscript author. M.S.: Study design, manuscript author. A.A.: Study design, data collection, manuscript author. Funding None. Conflicts of interest None. Ethics approval Not required.
References Adams C. 2010. Anaesthetic implications of acute and chronic alcohol abuse. South African Journal of Anaesthesiology and Analgesia, 16(3): 42–49. Archbold S., Lutman M.E., Marshall D.H. 1995. Categories of auditory performance. Annals of Otology, Rhinology & Laryngology. Supplement, 166: 312–314. Audit Scotland. 2009. Drug and alcohol services in Scotland report [viewed 2013 Nov 22]. Available from: http://www.audit-scot land.gov.uk/docs/health/2009/nr_090326_drugs_alcohol.pdf
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Beeston C., McAuley A., Robinson M., Craig N., Graham L. 2012. Monitoring and evaluating Scotland’s alcohol strategy: 2nd annual report. Edinburgh: NHS Health Scotland [viewed 2013 Nov 22]. Available from: http://www.healthscotland .com/documents/6182.aspx. Bench J., Kowal A., Bamford J. 1979. The BKB (Bamford-KowalBench) sentence lists for partially-hearing children. British Journal of Audiology, 13(3): 108–112. Brant L.J., Gordon-Salant S., Pearson J.D., Klein L.L., Morrell C.H., Metter E.J., et al. 1996. Risk factors related to age-associated hearing loss in the speech frequencies. Journal of American Academy of Audiology, 7: 152–160. Curhan S.G., Eavey R., Shargorodsky J., Curhan G.C. 2010. Prospective study of alcohol use and hearing loss in men. Ear and Hearing, 32: 46–52. Dutt S.N., Ray J., Hadjihannas E., Cooper H., Donaldson I., Proops D.W. 2005. Medical and surgical complications of the second 100 adult cochlear implant patients in Birmingham. Journal of Laryngology and Otology, 119(10): 759–764. Fransen E., Topsakal V., Hendrickx J.J., Van Laer L., Huyghe J.R., Van Eyken E., et al. 2008. Occupational noise, smoking, and a high body mass index are risk factors for age-related hearing impairment and moderate alcohol consumption is protective: a European population-based multicenter study. Journal of the Association of Research in Otolaryngology, 9(3): 264–276. Hallam R., Ashton P., Sherbourne K., Gailey L. 2006. Acquired profound hearing loss: mental health and other characteristics of a large sample. International Journal of Audiology, 45: 715–723. Hodgson R., Alwyn T., John B., Thom B., Smith A. 2002. The FAST alcohol screening test. Alcohol and Alcoholism, 37(1): 61–66. Meerton L.J., Andrews P.J., Upile T., Drenovak M., Graham J.M. 2005. A prospective randomized controlled trial evaluating alcohol on loudness perception in cochlear implant users. Clinical Otolaryngology, 30: 328–332. Mo B., Lindbæk M., Harris S. 2005. Cochlear implants and quality of life: a prospective study. Ear and Hearing, 26(2): 186–194. Pearson P., Dawe L.A., Timney B. 1999. Frequency selective effects of alcohol on auditory detection and frequency discrimination thresholds. Alcohol and Alcoholism, 34(5): 741–749. Popelka M.M., Cruickshanks K.J., Wiley T.L., Tweed T.S., Klein B.E., Klein R., et al. 2000. Moderate alcohol consumption and hearing loss: a protective effect. Journal of the American Geriatrics Society, 48: 1273–1278.
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Prakash R., Mullen K.D. 2010. Mechanisms, diagnosis and management of hepatic encephalopathy. Nature Reviews Gastroenterology & Hepatology, 7(9): 515–525. Robinette M.S., Brey R.H. 1978. Influence of alcohol on the acoustic reflex and temporary threshold shift. Archives of Otolaryngology, 104: 31–37. Robinson M., Shipton D., Walsh D., Whyte B., McCartney G. 2013. Monitoring and evaluating Scotland’s alcohol strategy: a comparison of alcohol sales and alcohol-related mortality in Scotland and Northern England. Edinburgh: NHS Health Scotland. Rosenhall U., Sixt E., Sundh V., Svanborg A. 1993. Correlations between presbyacusis and extrinsic noxious factors. Audiology, 32: 234–243. Scottish Intercollegiate Guidelines Network – SIGN. 2003. The management of harmful drinking and alcohol dependence in primary care [viewed 2013 Nov 22]. Available from: http:// www.sign.ac.uk/pdf/sign74.pdf. Seidman M.D., Quirk W.S., Shirwany N.A. 1999. Mechanisms of alterations in the microcirculation of the cochlea. Annals of the New York Academy of Sciences, 884: 226–232. Spies C.D., von Dossow V., Eggers V., Jetschmann G., El-Hilali R., Egert J., et al. 2004. Altered cell-mediated immunity and increased postoperative infection rate in long-term alcoholic patients. Anesthesiology, 100(5): 1088–1100. Summerfield A.Q., Marshall D.H. 1995. Cochlear implantation in the UK 1990–1994. Report by the MRC Institute of Hearing Research on the Evaluation of the National Cochlear Implant Programme. Main Report. London: Her Majesty’s Stationary Office. Verma R.K., Panda N.K., Basu D., Raghunsthan M. 2006. Audiovestibular dysfunction in alcohol dependence. Are we worried? American J Otolaryngology. Head and Neck Medicine and Surgery, 27: 225–228. Whyte B., Ajetunmobi T. 2012. Still “The sick man of Europe”? Scottish Mortality in a European Context 1950–2010. An analysis of comparative mortality trends. Glasgow Centre For Population Health [viewed 2013 Nov 22]. Available from: http://www.scotpho.org.uk/publications/reports-and-papers/ 937-still-the-sick-man-of-europe-scottish-mortality-in-a-euro pean-context-1950-2010-an-analysis-of-comparative-mortalitytrends. World Health Organization. 1992. International statistical classification of diseases and related health problems. 10th ed. Geneva: The Organization.
Cochlear implantation and alcohol misuse Lyndsay Fraser, Mary Shanks, Peter Wardrop, Agnes Allen Scottish Cochlear Implant Service, Crosshouse Hospital, Kilmarnock, UK Objective: To assess the outcome of patients referred to our national centre for cochlear implantation who have a history of alcohol misuse. Methods: A retrospective case-note review from 1989 – current was performed. Information was collected on aetiology/duration of deafness, current alcohol habits, and co-morbidities. For those implanted, we assessed implant type, anaesthetic, and complications. Our team rated each patients’ engagement with the rehabilitation programme and collected 9-month post-implant Bamford–Kowal–Bench (BKB) and 1-year post-implant categories of auditory performance (CAP) scores. Results: Fourteen patients with a history of harmful drinking or alcohol dependency were identified. Aetiology of deafness was varied but most commonly included sensorineural hearing loss of unknown aetiology (7), neomycin ototoxicity (3), and head injury (2). Twelve were suitable for implantation and 11 have been successfully implanted. Three patients experienced a post-operative complication (one major/two minor). Most (eight) were rated as having good engagement with the rehabilitation process and three rated as average. Nine-month post-implant BKB scores ranged from 10 to 92 (mean 56). One-year post-implant CAP scores range from 4 to 8. Conclusion: Patients with a background of alcohol misuse are being increasingly referred to our service. Alcohol is often implicated in the aetiology of deafness or can be sequelae of the psychological issues sometimes experienced by deaf patients. Even in the case of active alcohol misuse at the time of implantation, all surviving patients are currently active users and our results show that these patients can do well following implantation with the right support. Keywords: Cochlear implant, Alcohol, Outcomes
Introduction Cochlear implants have revolutionized the management of patients with severe to profound hearing loss over the past 30 years. Improving technology and outcomes has led to an expansion of the selection criteria for potentially suitable candidates. At our national centre for cochlear implantation, we have observed a steady increase in the number of patients with a history of alcohol problems being referred to us in recent years. Scotland is known to have high levels of alcohol misuse compared to the rest of the UK, with an estimated 4.9% of the population aged over 16 dependent on alcohol (Audit Scotland, 2009). Scotland has one of the highest rates of alcohol-related harm in Western Europe (Whyte and Ajetunmobi, 2012) and in 2010 alcohol-related deaths were double those found in England and Wales (Beeston et al., 2012). Assessment of suitability for implantation can be
Correspondence to: Lyndsay Fraser, Scottish Cochlear Implant Service, Crosshouse Hospital, Kilmarnock KA2 0BE, UK. Email: [email protected]
© W. S. Maney & Son Ltd 2015 DOI 10.1179/1754762814Y.0000000089
difficult in such patients for a variety of reasons and outcomes in this patient group have not yet been described in the literature. We describe our experience of 14 patients with a background of alcohol excess referred for cochlear implant assessment.
Study design Retrospective case series.
Methods Patients with either current or previous excessive alcohol consumption, as documented in their original referral correspondence, were identified from our departmental database from 1989 – current. According to ICD-10, problems with alcohol can be classified into two main categories; ‘harmful drinking’ is defined as a pattern of drinking that causes damage to physical or mental health while ‘alcohol dependence’ is defined as a cluster of physiological, behavioural, and cognitive phenomena in which the use of alcohol takes on a much higher priority for an individual than other behaviours that previously had greater
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value (World Health Organization, 1992). We included patients with either diagnosis. Casenotes and programming data were retrospectively reviewed. We collected information on age, sex, aetiology and duration of deafness, current reported alcohol intake, and co-morbidities. For those found suitable for implantation, we collected data on type of implant, anaesthetic grading/type of anaesthesia, and complications. We asked our cochlear implant team to rate each patients’ engagement with the rehabilitation programme as either poor, average, or good and collected 9-month post-implant Bamford–Kowal–Bench (BKB) scores and 1-year post-implant categories of auditory performance (CAP) scores. The BKB sentence test (Bench et al., 1979) is a popular open-set speech perception test developed for use with children and adults. The test can be administered in quiet conditions or in the presence of background noise and is scored depending on the number of correct words correctly identified. The mean BKB sentence score for adult cochlear implant users within our unit is 59%. CAP is a non-linear hierarchical scale which is used to measure the development of speech recognition ability and functional hearing. Although originally designed for use in hearing impaired children (Archbold et al., 1995) with seven categories, the scale has been modified over the years to include additional items that address the more complex listening skills achievable with a cochlear implant and can be applied to adults also. Over the period of our review, our patients were assessed with the eight category CAP scale used by Summerfield and team in their national review of UK cochlear implantation Table 1
CAP score 1 2 3
4
5 6 7 8
52
Categories of auditory performance % of implant patients achieving CAP level in our unit
Description Can detect environmental sounds Can identify at least five environmental sounds Understanding of common phrases is enhanced with cochlear implant (and lip-reading) Understanding of conversation is enhanced with cochlear implant (and lip-reading) Can understand common phrases without lip-reading Can understand conversation without lip-reading Can use telephone with a familiar talker Can use the telephone with an unfamiliar talker
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(Summerfield and Marshall, 1995) (Table 1). In this report, it was recommended that the majority of adult patients should achieve at least the first five abilities within 12 months of implantation. To allow for interpretation of the CAP scores from our series, Table 1 also demonstrates the percentage of our total implant population that achieves each of the abilities within the first 12 months after implantation.
Results From 1989 to present, 14 patients (8 female, 6 male) with a history of either harmful drinking or alcohol dependency were referred for cochlear implant assessment. Eleven of these patients have been referred within the past 5 years. The mean age was 56 (range 32–72). Aetiology of deafness was varied: seven sensorineural hearing loss (SNHL) of unknown aetiology (six sudden, one progressive), three neomycin ototoxicity after treatment for hepatic encephalopathy, two head injuries, one childhood mumps, and one patient with previous chemical labyrinthectomy for unilateral Meniere’s disease followed by sudden onset SNHL in the contralateral ear. Mean duration of deafness in the better hearing ear was 2 years and 7 months (range 6 months to 13 years). Of the 14 patients referred, 1 died before initial clinic review and 1 is currently undergoing assessment. Twelve have been found suitable for implantation and 11 have been successfully implanted. Our unit is currently supporting 703 adult patients implanted since 1989, so this patient group therefore makes up 1.7% of our implant population. One patient died of complications of alcohol abuse before implantation could be performed. Table 2 displays the demographics of the implanted patients including current alcohol habits at the time of surgery. Most patients had a fairly extensive past medical history with 7 out of 11 having established alcoholic liver disease. The average American Society of Anaesthesiology grading was 3, equating to severe systemic disease. Despite this, all but one was found suitable for general anaesthesia. Patient 9 was deemed too unfit for general anaesthesia but was motivated to proceed with surgery under local anaesthetic. Choice of device is usually left to the patient within our unit; seven chose Nucleus devices (one Nucleus mini-system 22, one Nucleus C124M, three Nucleus CI24RE, one Nucleus CI512, and one Nucleus CI422) and four chose Medel (Medel MI1000). Most patients (eight) were rated as having good engagement with the post-implantation rehabilitation process. Three were rated as average and none as poor. All patients that had pre-operative BKB scores recorded (9 of 11) scored 0%. Nine-month postimplant BKB scores were available for eight patients
Table 2 Patient demographics
Aetiology of deafness
Duration deafness in better hearing ear (years) Abstinent?
Co-morbidities
ASA grade
Complications
Preimplant BKB (%)
9-month BKB (%)
12-month CAP
NR
10
4
Good Good
0 0
66 NR
6 5
Good
0
82
8
Patient engagement
13
No
COPD
3
2 3
Mumps SSNHL
3 1
No 6 months
Polydrug abuse, anxiety/depression Alcoholic liver disease, peripheral neuropathy, psoriasis
1 3
4
0.5
3 months
COPD, hypertension
2
5
Chemical labyrinthectomy for Meniere’s and contralateral SSNHL SSNHL
Peri-operative CSF leak due to low dura. Settled conservatively None Post-operative wound infection requiring explantation at 4 months. Reimplanted at 8 months None
4
5 years
3
None
Good
0
26
6
6
Neomycin ototoxicity
1
3 years
3
None
Average
0
92
6
7
PSNHL
5
10 years
3
None
Good
0
85
8
8
Head injury
1
1 year
3
NR
52
7
SSNHL
1
5 years
3
Post-operative wound infection managed conservatively None
Average
9
Good
0
31
6
1.5
3 years
3
None
Good
0
Awaited
Awaited
1
1 year
Alcoholic liver disease, hypertension, hiatus hernia Alcoholic liver disease, peripheral neuropathy, anxiety/depression Type 2 diabetes, COPD, peripheral neuropathy, left ventricular hypertrophy Alcoholic liver disease, chronic subdural haematoma, hypertension, hypothyroidism Alcoholic liver disease, chronic renal failure, Barrett’s oesophagus, duodenal ulcer, asthma, hypertension, right heart failure Alcoholic liver disease, cerebral atrophy, chronic renal failure Alcoholic liver disease, hypertension, non-healing fracture of ankle
3
None
Good
0
Awaited
Awaited
10 Neomycin ototoxicty 11 SSNHL
Average
2015
SSNHL, sudden onset sensorineural hearing loss of unknown aetiology; PSNHL, progressive sensorineural hearing loss of unknown aetiology; COPD, chronic obstructive pulmonary disease; NR, not recorded; BKB, Bamford–Kowal–Bench test; CAP, categories of auditory performance; ASA, American Society of Anaesthesiology.
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Head injury
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and ranged from 10 to 92 (mean 56). Nine-month BKB scores are awaited in two patients who were recently implanted and are missing for one patient due to difficulty attending appointments due to issues with ill health and transport. One-year postimplant CAP scores are also displayed in Table 2. All patients are currently active users apart from patient 3 who died 5 years post-implantation and patient 7 who died 1 year post-implantation.
Discussion We have noted a sharp increase in the number of patients referred to us with a background of alcohol problems over the past 10 years. This is likely due to a combination of factors and may reflect the general trend of increasing alcohol sales and alcohol-related morbidity within Scottish society (Robinson et al., 2013). In addition, an awareness of widening criteria for cochlear implantation may have led to patients being referred who might previously have been assumed to be poor candidates due to their accompanying co-morbidities or predicted poor engagement with the rehabilitation process. Aetiology of deafness in our cohort was varied, with the most common reason being SNHL of unclear aetiology. Although it is difficult to pinpoint alcohol as the specific cause in these patients due to inconsistent documentation of duration of alcohol misuse within their records, chronic alcohol abuse is known to be associated with an increased risk of hearing loss (Rosenhall et al., 1993; Verma et al., 2006) and no other obvious causes were identified. Alcohol is known to elevate the acoustic reflex threshold, increase temporary threshold shift (Robinette and Brey, 1978), and cause elevation of high-frequency thresholds (Verma et al., 2006). Although alcohol is known to affect those aspects of hearing which require higher levels of central auditory processing (hearing under difficult listening conditions, hearing at lower frequencies, monaural versus binaural hearing, and discrimination of higher frequencies versus lower frequencies), the exact sites of action remain unknown (Pearson et al., 1999). The relationship between low-to-moderate levels of alcohol consumption and hearing remains less clear cut. A protective association has been observed in some studies (Popelka et al., 2000; Fransen et al., 2008) but not in others (Brant et al., 1996). It has been proposed that the cardioprotective effects of moderate alcohol intake, such as higher high-density lipoprotein cholesterol and antithrombotic activity, may translate to a decreased risk of hearing loss by potentially protecting against disturbances in cochlear blood flow (Seidman et al., 1999). Curhan et al. (2010) found that patients who had a lower intake of vitamin B12 coupled with high alcohol consumption had an
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increased risk of hearing loss, suggesting a possible co-factor. Neomycin ototoxicity following treatment for hepatic encephalopathy was the second most common aetiology encountered. Hepatic encephalopathy is a serious and potentially fatal neuropsychiatric complication of both acute and chronic liver disease and neomycin acts by inhibiting mucosal glutaminase in the intestine, which reduces ammonia production in the gut. The drug is associated with several well-established side effects including ototoxicity, nephrotoxicity, and intestinal malabsorption and its use has steadily declined in recent years due to the availability of safer antibiotics such as rifaximin (Prakash and Mullen, 2010). The majority of patients (82%) reported abstinence from alcohol at the time of surgery. We do not routinely monitor blood markers of excessive alcohol consumption (elevated mean red blood cell volume or serum gamma glutamyl transferase) as false positives can occur and self-reported consumption is usually taken as the ‘gold standard’ (Scottish Intercollegiate Guidelines Network, 2003). Excessive alcohol consumption was a factor for two patients at the time of surgery. Although not ideal, we decided to proceed with implantation as each patient was felt to be sufficiently motivated and likely to gain benefit on preimplant assessment. We felt that each patient’s continued alcohol misuse was due to ongoing psychological problems related to their profound hearing loss and that this was likely to be eased by implantation (Mo et al., 2005). Profound hearing loss not only causes substantial impairments in important life domains such as social functioning and capability to perform daily activities, but also significantly impacts on mental health making those affected more vulnerable to depression (Hallam et al., 2006). We do not routinely screen for alcohol misuse or depression when we assess patients but instead rely on diagnostic information in the referral correspondence or information given by the patient. We acknowledge that it is therefore possible that other patients coming through our service have experienced or are currently experiencing problems relating to alcohol, but that their problems have remained subclinical. It is also possible that some patients who were referred and subsequently found to be unsuitable for cochlear implantation could have had a history of alcohol misuse that we have not been aware of. Unfortunately, due to the large number of referrals since 1989 and probable lack of documentation of alcohol issues (particularly in the early days of the programme when fewer were being referred and awareness of the issue was lower), we are unable to quantify this with a figure. No patient has ever been turned down solely on the basis of alcohol misuse. While social factors such as
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homelessness, poor family support, and criminal record are important in this group and would play a part in decision making, none would be completely exclusive. Each issue would need to be reviewed individually in the context of the patient’s audiology, medical history, motivation, and overall likelihood of gaining benefit. Where social factors are an issue, we would aim to support the patient directly by liasing with the correct agencies and have done this with success in the past. If severe co-morbidity is an issue, then this of course has implications for suitability for surgery but again would be assessed on an individual basis, with local anaesthetic remaining an option if general anaesthesia is contraindicated (as in patient 9). Patients with severe social disruption and significant co-morbidity are likely to be unsuitable candidates, but it has been our experience that these patients are not referred on for assessment by peripheral centres from the outset. Three of our implanted patients (27%) in this series experienced a peri- or post-operative complication (one major and two minor), which is slightly higher than average in a UK adult cochlear implant population (Dutt et al., 2005). Wound infection was the commonest issue, which is unsurprising given the increased rate of post-operative infection seen in patients with a history of chronic alcohol abuse (Spies et al., 2004). Peri-operative patient movement was an issue with patient 9 who underwent local anaesthetic implantation and although surgically challenging, implant insertion was performed successfully. Our patient group also posed a particular challenge for our anaesthetic team, as previous or current alcohol excess is known to predispose to intra-operative pulmonary and cardiac dysfunction, metabolic disturbance, and altered pharmacokinetics with common anaesthetic drugs (Adams, 2010). Fortunately, no anaesthetic complications were encountered. One-year post-operative CAP scores improved for all patients and ranged from 4 to 8. Most patients appear to be engaging well with the rehabilitation process. It is however very difficult to ascertain which of our patients continued to misuse alcohol despite cochlear implantation, as this is not formally assessed at programming appointments. However, as a result of a raised awareness of alcohol issues among our patients, we are keen to monitor those with known alcohol issues throughout their implantation journey and have begun to issue a Fast Alcohol Screening Test (Hodgson et al., 2002) and depression questionnaire at each visit to allow us to identify patients who have continued dependency and require additional support. The effects of alcohol on the psychophysical responses during cochlear implant mapping have been investigated by Meerton et al. (2005). The
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authors showed that alcohol consumption 1 hour before programming significantly increases the upper end of the dynamic range (‘comfort level’) in cochlear implant patients in comparison with placebo. This effect was felt to be likely due to the result of change in the auditory pathways proximal to the cochlea. We have not noticed such an effect during programming sessions, although this may be due to the fact that we have had very few patients attend for programming actively intoxicated. Funding for cochlear implantation in Scotland is provided by central government to offer implantation for all suitable candidates who meet the selection criteria and candidature is determined by the team’s assessment of overall likelihood of gaining benefit. We have not therefore experienced any funding issues with implanting this particular patient group.
Conclusion Patients with a history of alcohol misuse are being increasingly referred to our national cochlear implant service. Outcomes in this patient group have not yet been described. Alcohol misuse is often implicated in the aetiology of deafness, or is sequelae of the psychological issues and social isolation that some profoundly deaf patients experience. Associated comorbidity is often a concern and makes anaesthesia and surgery more fraught, with post-operative infection a particular risk in this patient group. Even in the case of active alcohol misuse at the time of implantation, all surviving patients are currently active users and our results show that these patients can do well following implantation with the right support.
Disclaimer statements Contributors L.F.: Data collection, literature review, manuscript author. P.W.: Study design, manuscript author. M.S.: Study design, manuscript author. A.A.: Study design, data collection, manuscript author. Funding None. Conflicts of interest None. Ethics approval Not required.
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