Laura Vitkus, MPH, University of Arizona Center on Aging
Nicole Marrone, PhD, CCC-A, Speech, Language, and Hearing Sciences, University of Arizona
Elizabeth Glisky, PhD, College of Science, Department of Psychology, University of Arizona
|TIPS FOR CONDUCTING COGNITIVE ASSESSMENT WITH HEARING LOSS
Effects of Hearing Loss on Cognitive Assessment
Research has demonstrated an association between hearing loss and low scores on both verbal and non-verbal cognitive tests in older adults. Hearing loss affects 2/3 of adults over 70. Most standardized cognitive assessment tests used by clinicians include items that rely on hearing for successful completion of the assessment. For example, the most commonly used tests require the repetition or recall of spoken words, letters, numbers, or sentences. And, even for assessments that do not require verbal responses, the instructions are provided verbally so hearing impairment can influence performance.
An example is the widely used Montreal Cognitive Assessment (MoCA), in which 3 of 8 components require the ability to hear. The MoCA requires the tester to read a list of letters, during which the subject must tap the tester's hand at each letter A. Additionally, this test includes a list of numbers to be read aloud and repeated in order, and a shorter list to be read and repeated in reverse order.
Table 1 shows seven commonly used screening tools and the role of hearing in each. The AD8 and IQCODE are the only two in which hearing alone would not influence the results, but both require the patient to read. Therefore, a patient with hearing loss and low vision might struggle to perform these tests. Both, however, ask for information that can be provided by a caregiver of the patient.
|Table 1. Hearing Plays a Role in Many Cognitive Assessment Tests|
Role of Hearing in Test Administration
|AD8 Dementia Screening Interview (AD8)||None, unless test is read aloud due to visual impairment|
|General Practitioner Assessment of Cognition (GPCOG)||Recall of a name and address, immediate and delayed|
|Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE)||None, unless test is read aloud due to visual impairment|
|Memory Impairment Screen (MIS)||Minimal, unless visual impairment prevents patient from reading word cues|
|Mini-Cog Screening for Cognitive Impairment||3-word recall, immediate and delayed|
|Mini-Mental State Exam (MMSE)||3-word recall, immediate and delayed; repeat a spoken phrase|
|Montreal Cognitive Assessment (MoCA)||5-word recall, immediate and delayed; letter and number attention; repeat a spoken phrase|
This combination of hearing impairment and low vision (dual-sensory impairment) is common in older adults. About 11% of American adults aged 80 and over have dual sensory impairment, and only 19% of people in this age group have no sensory impairment at all.
Hearing Loss Can Increase Dementia Risk
Studies have shown that hearing loss increases a person's risk of developing dementia. Even mild hearing loss (~25dBHL across frequencies) is associated with cognitive decline at a rate equivalent to 7 years of aging. The association between hearing impairment and dementia could be due to a decrease in nerve cell connectivity, social isolation, or overloading cognitive resources in an effort to process auditory stimuli.
Environmental sounds and speech recognition can be difficult to comprehend in the presence of decreased central auditory processing ability. Such a deficit could be related to dementia or indicate impaired temporal lobe function in an aging central auditory system.
Whatever the cause, the risk of dementia increases with the severity of hearing impairment. Individuals with mild hearing loss have twice the risk of dementia compared to individuals without hearing impairment. Those with severe hearing loss have 5-times the risk.
Clinical Presentation of Hearing Loss and Dementia
Some common symptoms of hearing loss are similar to the communication deficiencies experienced by individuals with dementia, sometimes making it difficult to differentiate hearing loss from dementia. Table 2 gives a brief explanation of how and why similar symptoms can occur in both conditions.
|Table 2. Symptoms That May Overlap Between Hearing Loss and Dementia|
|Symptom||Why it Occurs in Hearing Loss||Why it Occurs in Dementia|
|Hyperacusis (sound aversion, sounds sensitivity)||Abnormal processing of received auditory stimuli||Reduction in central auditory processing|
|Difficulty comprehending speech in settings with background noise||Decreased processing range of decibels||Decreased attention or executive function|
|Trouble discriminating location of sounds||Loss of peripheral hearing sensitivity||Inability to cognitively determine location of sounds|
Patients with hearing loss may be using more of their cognitive resources to understand spoken language, thus increasing their "cognitive load." As a result, they may perform poorly on tests of both memory and executive function. It is common for those with age-related hearing loss to say that they can "hear but not understand."
Patients with dementia, on the other hand, may be able to hear spoken language without difficulty, but struggle to understand meaning in the words.
In-office cognitive screening tools are designed for easy use and require minimal training. They generally take only 3-10 minutes to conduct. Because of these characteristics, they are widely used in clinical practice for assessing cognitive ability and often essential for early detection of dementia. It is important to consider hearing impairment when using these assessment tools, as hearing impairment can influence results and lead to an incorrect diagnosis of cognitive impairment or dementia.
Assessing Cognitive Function with Hearing Impairment
When hearing loss is present or suspected, several steps should be taken to increase the likelihood of an accurate assessment. The best approach is to correct for the hearing deficit, if possible. Encourage patients to wear their hearing aids during cognitive assessments, and, if they don't have one, consider using an amplification device. Conduct the assessment in a quiet room using an assessment that minimizes auditory requirements, and sit so the patient can see your mouth and lips when you speak (Table 3.)
Table 3. What To Do When Hearing Loss is Present or Suspected During Cognitive Assessment
References and Resources
- Dupuis K, Pichora-Fuller MK, Chasteen AL, Marchuk V, Singh G, Smith SL. Effects of hearing and vision impairments on the Montreal Cognitive Assessment. Aging, Neuropsychol Dev Cogn B Agin Neuropsychol Cogn. 2015; 22(4):413-437.
- Hardy CJD, Marshall CR, Golden HL, et al.,. Hearing and dementia. J Neurol. 2016; 263(11), 2339- 2354.
- Harris, F., Muller, T. Elder Care - A Resource for Interprofessional Providers: Hearing Aids. POGOe - Portal of Online Geriatrics. ID: 20895.
- Lin FB, Metter J, O'Brien R, Resnick SM, Zonderman AB, Ferrucci L. Hearing loss and incident dementia. Arch Neurol. 2011; 68(2):214-220.
- Lin FR, Yaffe K, Kin X, et al. Hearing Loss and cognitive decline in older adults. JAMA Intern Med. 2013; 173(4):293-299.
- Vitkus, L., Stocker-Cioltan, H. & Marrone, N. (2017). Elder Care - A Resource for Interprofessional Providers: Hearing Loss: Epidemiology & Screening.