As one ages, the ability to communicate effectively may be altered by some normal changes in speech, language, swallowing, and hearing.1 The risk of experiencing hearing loss increases considerably with each additional decade, such that nearly half of the 76 million baby boomers in the United States will experience some degree of hearing impairment.2 Considered a major chronic condition, and recognized as a major public health problem, hearing impairment affects about 30% of the population over the age of 65 years; for individuals older than 75 years, the number rises to 40% to 50% and is >80% in persons over the age of 85.2
Approximately eight million older adults have a speech, language, and/or hearing disorder that affects their ability to communicate on a daily basis; some individuals may experience more than one communication disorder, such as residual language problems secondary to a stroke in combination with an underlying hearing loss.1 Furthermore, ototoxic drugs (TABLE 1) are a common cause of hearing loss, especially in older adults who take these agents regularly.1,3
A significant increase in the number of older adults with a communication disorder in the years ahead—given the greying of America—is expected. Pharmacists can contribute to the healthy aging of our senior population by mitigating risk associated with ototoxic agents, in addition to raising awareness of hearing impairment and providing referrals where appropriate.
Age-Related Changes That Affect Communication
With regard to the physiologic, cognitive, and psychologic basis of aging, seniors undergo age-related changes that impact functional capacity (TABLE 2). The aging process causes numerous changes in speech, language, and swallowing (TABLE 3); the extent to which these changes affect communication functioning varies from person to person.1 One of the most common problems is tooth loss and compromised dentition; aging also produces tissue, glandular, and muscular changes in the jaw, tongue, salivary glands, and throat.4 A decrease in the number of salivary glands and reduced taste sensation also occurs with age.4
Age is the most critical risk factor for the auditory sense organ.5 Age-related hearing impairment, or presbycusis, is a progressive, bilaterally symmetrical, high frequency sensorineural hearing loss causing problems with speech discrimination.6 Presbycusis is associated with auditory system changes within the peripheral and central nervous system that cannot be attributed to ototraumatic, ototoxic, genetic, or pathologic conditions.7 Age-related hearing loss is a major predictive factor for tinnitus, commonly described as ringing in the ear, the prevalence of which increases with age.2 Permanent tinnitus is experienced by approximately 11% of patients suffering from age-related hearing loss.2 Age-related morphologic changes also take place in the vestibular system; in combination with changes in the ocular system associated with aging, older adults become increasingly susceptible to falls and dizziness.2 Overall, the biological aging of the auditory system is probably associated with multifaceted factors, including genetics, diet, exposure to noise, medications, viruses, infections, and systemic illnesses. While normal age-related changes are non-modifiable, noise-induced hearing loss is completely preventable; preventive measures should be employed to protect hearing sensitivity.8
Medication-Related Causes of Hearing Loss
Ototoxic drugs (TABLE 1) are a common cause of hearing loss, especially in older adults who have to take medicine on a regular basis. In most cases, hearing loss occurs secondary to cochlea damage in the inner ear.3 In general9:
• Drugs may cause hearing loss, tinnitus, and dysequilibrium
• Common drugs having this effect include aminoglycosides, platinum-containing chemotherapy drugs, and high-dose salicylates
• Symptoms may be transient or permanent
• Drugs are discontinued when appropriate; however, there is no specific treatment.
Tips for Prevention of Hearing Impairment: Focus on Drugs
Ototoxic drugs should not be used in elderly patients and individuals with preexisting hearing loss if other effective drugs are available; factors affecting ototoxicity are addressed in TABLE 1. Tips for the use of ototoxic drugs include9:
• Use lowest effective dosage
• Monitor drug levels closely, particularly both peaks and troughs for aminoglycosides
• Since symptoms are not reliable warning signs, hearing should be measured prior to and then monitored during treatment, if possible
• Avoid the use of multiple drugs with ototoxic potential
• Avoid ototoxic drugs in patients with renal impairment; if necessary, closer monitoring of drug levels is advised
• Do not topically apply otic preparations when the tympanic membrane is perforated, since diffusion into the inner ear may occur.
Referral
If the hearing status of a patient is a concern, it is recommended that a referral to an American Speech-Language-Hearing Association (ASHA)-certified audiologist be sought for an audiological evaluation to determine the type and degree of hearing loss.1 Such professionals can discuss with patients the value of available medical and nonmedical interventions, including the use of hearing aids and techniques to improve the perception of sound (e.g., environmental-sound training that aids the listener in navigating his or her environment).10
Conclusion
Almost every older individual can expect to experience normal age-related changes in the auditory system; multimorbidity may complicate this scenario. Additionally, ototoxic drugs are a common cause of hearing loss, especially in older adults who take them regularly. Patients, family members, and caregivers stand to benefit from early identification of hearing and balance problems and the preventative measures by pharmacists regarding medication-related potential causes.
REFERENCES
1. Busacco D. Normal communication changes in older adults. Let’s Talk. The American Speech-Language-Hearing Association. 1999; January-February (72):49-50.www.asha.org/uploadedFiles/publications/archive/0499ashamag.pdf. Accessed December 2, 2015.
2. Weinstein B. Disorders of hearing. In: Fillit HM, Rockwood K, Woodhouse K, eds. Brocklehurst’s Textbook of Geriatric Medicine and Gerontology. 7th ed. Philadelphia, PA: Saunders Elsevier; 2010:822-834.
3. WebMD.com. Medicines that cause hearing loss. Last updated: November 14, 2014. www.webmd.com/a-to-z-guides/medicines-that-cause-hearing-loss-topic-overview. Accessed December 2, 2015.
4. Sonies B. Oral motor problems. In: Mueller HG, Geoffrey VC, eds. Communication disorders in aging. Washington, DC: Gallaudet University. 1987:185-213.
5. Moscicki E, Elkins E, Baum H, et al. Hearing loss in the elderly: an epidemiologic study of the Framingham Heart Study Cohort. Ear Hearing. 1985;6:184-190.
6. Reuben DB, Herr KA, Pacala JT, et al. Geriatrics at Your Fingertips: 2015. 17th ed. New York: The American Geriatrics Society; 2015:138-142.
7. Willott J, Chisolm T, Lister J, et al. Modulation of presbycusis: current status and future directions. Audiol Neurotol. 2001;6:231-249.
8. Hearing Loss Association of America (HLAA). Noise pollution: learn how to protect your ears! www.hearingloss.org/content/prevention-hearing-loss. Accessed December 18, 2015.
9. Merck Manual. Drug-induced ototoxicity. Last full review/revision June 2015. www.merckmanuals.com/professional/ear,-nose,-and-throat-disorders/inner-ear-disorders/drug-induced-ototoxicity. Accessed December 11, 2015.
10. Shafiro V, Sheft S, Gygi B, et al. The influence of environmental sound training on the perception of spectrally degraded speech and environmental sounds. Trends Amplif. 2012;16(2)83-101.
11. Epocrates.com. Epocrates Plus Version 15.11. Updated December 14, 2015.
12. Semla TP, Beizer JL, Higbee MD. Geriatric Dosage Handbook. 19th ed. Hudson, OH: Lexicomp; 2014.
13. Mudd PA, Meyers AD. Ototoxicity. Updated October 23, 2014. http://emedicine.medscape.com/article/857679-overview#a4. Accessed January 4, 2016.
14. American Academy of Neurology. Geriatric Neurology Fellowship Core Curriculum. www.aan.com/trainees/fellowship-resources/core-curricula. Accessed December 11, 2015.
15. Ney D, Weiss J, Kind A, et al. Senescent swallowing: impact, strategies and interventions. Nutr Clin Pract. 2009;24(3):395-413. www.ncbi.nlm.nih.gov/pmc/articles/PMC2832792/. Accessed December 13, 2015.
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