Hearing Loss and Cognition Among Older Adults in the United States
01 Oct 2011-Journals of Gerontology Series A-biological Sciences and Medical Sciences (Oxford University Press)-Vol. 66, Iss: 10, pp 1131-1136
TL;DR: Hearing loss is independently associated with lower scores on the Digit Symbol Substitution Test, and whether hearing loss is a modifiable risk factor or an early marker of cognitive decline is needed.
Abstract: sample of older adults. Methods. We analyzed data from the 1999 to 2002 cycles of the National Health and Nutritional Examination Survey during which participants aged 60–69 years (n = 605) underwent both audiometric and cognitive testing. Hearing loss was defined by a pure tone average of hearing thresholds at 0.5, 1, 2, and 4 kHz in the better hearing ear. Cognitive testing consisted of the Digit Symbol Substitution Test (DSST), a nonverbal test that assesses executive function and psychomotor processing. Data on hearing aid use, demographics, and medical history were obtained from interviews. Regression models were used to examine the association between hearing loss and cognition while adjusting for confounders. Analyses incorporated sampling weights to yield results that are generalizable to the U.S. population. Results. Greater hearing loss was significantly associated with lower scores on the DSST after adjustment for demo graphic factors and medical history (DSST score difference of −1.5 [95% confidence interval : −2.9 to −0.23] per 10 dB of hearing loss). Hearing aid use was positively associated with cognitive functioning (DSST score difference of 7.4 [95% confidence interval : −0.62 to 15.4]). The reduction in cognitive performance associated with a 25 dB hearing loss was equivalent to the reduction associated with an age difference of 7 years. Conclusions. Hearing loss is independently associated with lower scores on the DSST. Further research is needed to determine whether hearing loss is a modifiable risk factor or an early marker of cognitive decline.
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Camden and Islington NHS Foundation Trust1, University College London2, King's College London3, University of Melbourne4, University of Exeter5, Brighton and Sussex Medical School6, University of Manchester7, Tel Aviv University8, Johns Hopkins University9, University of Michigan10, University of Washington11, Kaiser Permanente12, University of Edinburgh13, University of Montpellier14, Dalhousie University15, University of Southern California16, University of Oslo17, Innlandet Hospital Trust18
TL;DR: The Lancet Commission on Dementia Prevention, Intervention, and Care met to consolidate the huge strides that have been made and the emerging knowledge as to what the authors should do to prevent and manage dementia.
3,826 citations
TL;DR: Hearing loss is independently associated with accelerated cognitive decline and incident cognitive impairment in community-dwelling older adults and the mechanistic basis of this association is and whether hearing rehabilitative interventions could affect cognitive decline is investigated.
Abstract: Background:Whetherhearinglossisindependentlyassociatedwithacceleratedcognitivedeclineinolderadults is unknown. Methods:Westudied1984olderadults(meanage,77.4 years) enrolled in the Health ABC Study, a prospective observational study begun in 1997-1998. Our baseline cohort consisted of participants without prevalent cognitive impairment (Modified Mini-Mental State Examination [3MS] score, 80) who underwent audiometric testinginyear5.Participantswerefollowedupfor6years. Hearing was defined at baseline using a pure-tone average of thresholds at 0.5 to 4 kHz in the better-hearing ear. Cognitive testing was performed in years 5, 8, 10, and11andconsistedofthe3MS(measuringglobalfunction) and the Digit Symbol Substitution test (measuring executive function). Incident cognitive impairment was definedasa3MSscoreoflessthan80oradeclinein3MS score of more than 5 points from baseline. Mixedeffects regression and Cox proportional hazards regression models were adjusted for demographic and cardiovascular risk factors. Results: In total, 1162 individuals with baseline hearing loss (pure-tone average 25 dB) had annual rates of declinein3MSandDigitSymbolSubstitutiontestscoresthat were41%and32%greater,respectively,thanthoseamong individuals with normal hearing. On the 3MS, the annual score changes were 0.65 (95% CI, 0.73 to 0.56) vs 0.46(95%CI,0.55to0.36)pointsperyear(P=.004). On the Digit Symbol Substitution test, the annual score changes were 0.83 (95% CI, 0.94 to 0.73) vs 0.63 (95% CI, 0.75 to 0.51) points per year (P=.02). Comparedtothosewithnormalhearing,individualswithhearing loss at baseline had a 24% (hazard ratio, 1.24; 95% CI, 1.05-1.48) increased risk for incident cognitive impairment. Rates of cognitive decline and the risk for incident cognitiveimpairmentwerelinearlyassociatedwiththeseverity of an individual’s baseline hearing loss.
1,223 citations
TL;DR: There are a number of factors that limit CI outcomes that can act singularly or collectively to restrict an individual’s performance and to varying degrees and knowledge of when and how these factors affect performance can favorably influence counseling, device fitting, and rehabilitation for individual patients.
Abstract: Objective A great deal of variability exists in the speech-recognition abilities of postlingually deaf adult cochlear implant (CI) recipients. A number of previous studies have shown that duration of deafness is a primary factor affecting CI outcomes; however, there is little agreement regarding other factors that may affect performance. The objective of the present study was to determine the source of variability in CI outcomes by examining three main factors, biographic/audiologic information, electrode position within the cochlea, and cognitive abilities in a group of newly implanted CI recipients. Design Participants were 114 postlingually deaf adults with either the Cochlear or Advanced Bionics CI systems. Biographic/audiologic information, aided sentence-recognition scores, a high resolution temporal bone CT scan and cognitive measures were obtained before implantation. Monosyllabic word recognition scores were obtained during numerous test intervals from 2 weeks to 2 years after initial activation of the CI. Electrode position within the cochlea was determined by three-dimensional reconstruction of pre- and postimplant CT scans. Participants' word scores over 2 years were fit with a logistic curve to predict word score as a function of time and to highlight 4-word recognition metrics (CNC initial score, CNC final score, rise time to 90% of CNC final score, and CNC difference score). Results Participants were divided into six outcome groups based on the percentile ranking of their CNC final score, that is, participants in the bottom 10% were in group 1; those in the top 10% were in group 6. Across outcome groups, significant relationships from low to high performance were identified. Biographic/audiologic factors of age at implantation, duration of hearing loss, duration of hearing aid use, and duration of severe-to-profound hearing loss were significantly and inversely related to performance as were frequency modulated tone, sound-field threshold levels obtained with the CI. That is, the higher-performing outcome groups were younger in age at the time of implantation, had shorter duration of severe-to-profound hearing loss, and had lower CI sound-field threshold levels. Significant inverse relationships across outcome groups were also observed for electrode position, specifically the percentage of electrodes in scala vestibuli as opposed to scala tympani and depth of insertion of the electrode array. In addition, positioning of electrode arrays closer to the modiolar wall was positively correlated with outcome. Cognitive ability was significantly and positively related to outcome; however, age at implantation and cognition were highly correlated. After controlling for age, cognition was no longer a factor affecting outcomes. Conclusion There are a number of factors that limit CI outcomes. They can act singularly or collectively to restrict an individual's performance and to varying degrees. The highest performing CI recipients are those with the least number of limiting factors. Knowledge of when and how these factors affect performance can favorably influence counseling, device fitting, and rehabilitation for individual patients and can contribute to improved device design and application.
699 citations
Cites background from "Hearing Loss and Cognition Among Ol..."
...Using well-defined anatomical landmarks, we coregister with ANALYZE software (Mayo Clinic, Rochester; Robb 2001) an individual’s preimplant CT image voxel space optimized for anatomical detail with their postimplant CT image space optimized for resolution of the electrode. The electrode lead wires and contacts are identified, segmented from the postimplant image data, and copied into the preimplant image space to provide a composite image of electrode placement within an individual’s cochlea. To better visualize the scalar position of the segmented array and the individual electrode contacts, the aforementioned composite CT volume is then aligned with a high-resolution cochlear atlas to infer the location of fine and soft tissue intracochlear structures not resolved by CT, such as the basilar membrane. The atlas is based on an orthogonal-plane, fluorescence optical sectioning (OPFOS) microscopy scan of a single male donor with normal cochlear anatomy and illustrates details of both the soft tissue and bony structure of the cochlea (Voie et al. 1993). Figure 1 is a composite CT volume rendering of a participant’s lateral cochlear wall and electrode array viewed along the mid modiolar (MM) axis and shown with the markers and lines used to measure the participant’s cochlear dimensions and array position. The dark line and gray hash marks in Figure 1A show the path of the array and the location of the 22 electrode contacts of a Contour Advance array (E A = apical-most electrode, E B = basal-most electrode). Shown are the center of the round window, the cochleostomy site, the 0-degree start point, which marks the beginning of the cochlear canal as described in Skinner et al. (2007), the apex of the cochlea, the MM axis, and the 0-degree reference line....
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...They were asked to listen to simple and linguistically complex sentences and to press a button to indicate whether a male or female performed the action in the sentence. Results revealed a significant but inverse relationship between neural activity and hearing level as well as between gray matter volume in the right auditory cortex and hearing level. As the majority of participants in both studies had normal hearing or mild hearing loss, these results could potentially have a greater effect on older adults with SPHL. Lin (2011) and others suggest that hearing loss limits communication and social activities that may otherwise stimulate cognitive function....
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TL;DR: Age-related hearing loss is a possible biomarker and modifiable risk factor for cognitive decline, cognitive impairment, and dementia and a small but significant association was found within all domains of cognitive function.
Abstract: Importance
Epidemiologic research on the possible link between age-related hearing loss (ARHL) and cognitive decline and dementia has produced inconsistent results. Clarifying this association is of interest because ARHL may be a risk factor for outcomes of clinical dementia.
Objectives
To examine and estimate the association between ARHL and cognitive function, cognitive impairment, and dementia through a systematic review and meta-analysis.
Data Sources and Study Selection
A search of PubMed, the Cochrane Library, EMBASE, and SCOPUS from inception to April 15, 2016, with cross-referencing of retrieved studies and personal files for potentially eligible studies was performed. Keywords included hearing, cognition, dementia, and Alzheimer disease. Cohort and cross-sectional studies published in peer-reviewed literature and using objective outcome measures were included. Case-control studies were excluded.
Data Extraction and Synthesis
One reviewer extracted and another verified data. Both reviewers independently assessed study quality. Estimates were pooled using random-effects meta-analysis. Subgroup and meta-regression analyses of study-level characteristics were performed.
Main Outcomes and Measures
Hearing loss measured by pure-tone audiometry only and objective assessment measures of cognitive function, cognitive impairment, and dementia. Cognitive function outcomes were converted to correlation coefficients (r value); cognitive impairment and dementia outcomes, to odds ratios (ORs).
Results
Forty studies from 12 countries met our inclusion criteria. Of these, 36 unique studies with an estimated 20 264 unique participants were included in the meta-analyses. Based on the pooled maximally adjusted effect sizes using random-effects models, a small but significant association was found for ARHL within all domains of cognitive function. Among cross-sectional studies, a significant association was found for cognitive impairment (OR, 2.00; 95% CI, 1.39-2.89) and dementia (OR, 2.42; 95% CI, 1.24-4.72). Among prospective cohort studies, a significant association was found for cognitive impairment (OR, 1.22; 95% CI, 1.09-1.36) and dementia (OR, 1.28; 95% CI, 1.02-1.59) but not for Alzheimer disease (OR, 1.69; 95% CI, 0.72-4.00). In further analyses, study, demographic, audiometric, and analyses factors were associated with cognitive function. Vascular dysfunction and impaired verbal communication may contribute to the association between hearing loss and cognitive decline.
Conclusions and Relevance
Age-related hearing loss is a possible biomarker and modifiable risk factor for cognitive decline, cognitive impairment, and dementia. Additional research and randomized clinical trials are warranted to examine implications of treatment for cognition and to explore possible causal mechanisms underlying this relationship.
474 citations
Harvard University1, Case Western Reserve University2, University of Portland3, San Diego State University4, Brandeis University5, Rush University Medical Center6, University of California, San Francisco7, University of Wisconsin-Madison8, Columbia University9, University of Rochester10, University of California, Irvine11, University of Washington12, Medical University of South Carolina13, Albert Einstein College of Medicine14, Johns Hopkins University15, Boston University16, Washington University in St. Louis17, Mayo Clinic18, Southern Illinois University School of Medicine19, University of Pennsylvania20, Nathan Kline Institute for Psychiatric Research21, University of Southern California22
TL;DR: It is clear that sensory and motor regions of the central nervous system are affected by AD pathology and that interventions targeting amelioration of sensory‐motor deficits in AD may enhance patient function as AD progresses.
Abstract: Recent evidence indicates that sensory and motor changes may precede the cognitive symptoms of Alzheimer's disease (AD) by several years and may signify increased risk of developing AD. Traditionally, sensory and motor dysfunctions in aging and AD have been studied separately. To ascertain the evidence supporting the relationship between age-related changes in sensory and motor systems and the development of AD and to facilitate communication between several disciplines, the National Institute on Aging held an exploratory workshop titled "Sensory and Motor Dysfunctions in Aging and AD." The scientific sessions of the workshop focused on age-related and neuropathologic changes in the olfactory, visual, auditory, and motor systems, followed by extensive discussion and hypothesis generation related to the possible links among sensory, cognitive, and motor domains in aging and AD. Based on the data presented and discussed at this workshop, it is clear that sensory and motor regions of the central nervous system are affected by AD pathology and that interventions targeting amelioration of sensory-motor deficits in AD may enhance patient function as AD progresses.
412 citations
Cites background from "Hearing Loss and Cognition Among Ol..."
..., tests of memory and executive function) rather than cognitive tests focused on less complex speeded tasks [244,270,271]....
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References
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Book•
01 Jan 1955
5,425 citations
"Hearing Loss and Cognition Among Ol..." refers methods in this paper
...Cognitive Testing The DSST, a component of the Wechsler Adult Intelligence Test (18), was administered as per NHANES protocol (19)....
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15 Jul 2005
2,618 citations
TL;DR: An extensive social network seems to protect against dementia, and further investigation to clarify the mechanisms are worthwhile due to the implications for prevention.
1,241 citations
"Hearing Loss and Cognition Among Ol..." refers background in this paper
...Communication impairments caused by hearing loss can lead to social isolation in older adults (38,39), and epidemiologic (40,41) and neuroanatomic studies (42) have demonstrated associations between poor social networks and cognitive decline and dementia....
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TL;DR: Hearing loss is independently associated with incident all-cause dementia, and whether hearing loss is a marker for early-stage dementia or is actually a modifiable risk factor for dementia deserves further study.
Abstract: Objective To determine whether hearing loss is associated with incident all-cause dementia and Alzheimer disease (AD). Design Prospective study of 639 individuals who underwent audiometric testing and were dementia free in 1990 to 1994. Hearing loss was defined by a pure-tone average of hearing thresholds at 0.5, 1, 2, and 4 kHz in the better-hearing ear (normal, 70 dB [n = 6]). Diagnosis of incident dementia was made by consensus diagnostic conference. Cox proportional hazards models were used to model time to incident dementia according to severity of hearing loss and were adjusted for age, sex, race, education, diabetes mellitus, smoking, and hypertension. Setting Baltimore Longitudinal Study of Aging. Participants Six hundred thirty-nine individuals aged 36 to 90 years. Main Outcome Measure Incident caces of all-cause dementia and AD until May 31, 2008. Results During a median follow-up of 11.9 years, 58 cases of incident all-cause dementia were diagnosed, of which 37 cases were AD. The risk of incident all-cause dementia increased log linearly with the severity of baseline hearing loss (1.27 per 10-dB loss; 95% confidence interval, 1.06-1.50). Compared with normal hearing, the hazard ratio (95% confidence interval) for incident all-cause dementia was 1.89 (1.00-3.58) for mild hearing loss, 3.00 (1.43-6.30) for moderate hearing loss, and 4.94 (1.09-22.40) for severe hearing loss. The risk of incident AD also increased with baseline hearing loss (1.20 per 10 dB of hearing loss) but with a wider confidence interval (0.94-1.53). Conclusions Hearing loss is independently associated with incident all-cause dementia. Whether hearing loss is a marker for early-stage dementia or is actually a modifiable risk factor for dementia deserves further study.
1,108 citations
"Hearing Loss and Cognition Among Ol..." refers background in this paper
...1 AUDIOMETRIC hearing loss has recently been found to be independently associated with incident all-cause dementia in the Baltimore Longitudinal Study of Aging (1)....
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...(Psychol Aging 2005;20[1]:3.)...
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