THE ALZHEIMER’S ASSOCIATION reported 6.2 million Americans with Alzheimer’s Disease in 2021 (1), representing two-thirds of all dementia cases; with others estimating all-cause dementia will triple by 2050, approaching 30 million people.(2)
There are two generally accepted categories of neurocognitive disorders (NCDs):
- Mild cognitive impairment (MCI, a.k.a. Mild Neurocognitive Disorder) affects 22% of the 65 and over population (3). MCI manifests as decreased cognitive ability (forgetfulness, etc.) while maintaining activities of daily living. Approximately 20% of people with MCI convert to dementia annually (4).
- When daily activities, such as tending to one’s personal needs, become problematic or impossible, suspicion regarding major NCDs — which include Alzheimer’s Disease, fronto-temporal dementia, vascular dementia, Lewy Body dementia, and more — are heightened.
Extensive research offers hope for dementia related treatments. Medications such as lecanemab have demonstrated a slowing in the progression of cognitive decline in some patients. However, the improvement is not universal and adverse effects include brain edema and hemorrhage (5) prompting the recommendation that patients should have close monitoring for possible brain hemorrhage (6).
Since there is no absolute cure for dementia, the general strategy to address dementia remains to identify risk factors early and delay the progression from MCI to dementia. One study (7) reported that a one-year delay in conversion from MCI to dementia would decrease the global disease burden in 2050 by 10%.
Reports (8) indicate that 60% of dementia risk is from age and deoxyribonucleic acids, while 40% of dementia risk may be due to 12 potentially modifiable risk factors; less education, untreated hearing loss, traumatic brain injury, untreated hypertension, excessive alcohol consumption, untreated diabetes, smoking, obesity, depression, social isolation, physical inactivity and air pollution. Numerous studies have highlighted vision loss as a risk factor for dementia. Cognitive function improved following vision correction and cataract surgery (9). A study of 2,500+ adults found visual impairment is associated with declining cognitive function (10) and a meta-analysis of 40 studies found vision impairment increases the risk of cognitive impairment two-fold (11).
The most significant modifiable risk factor for dementia is hearing loss (12, 8, and 13). The LANCET in April 2023 (14) reported “…findings highlight the URGENT NEED to take measures to address hearing loss to improve cognitive decline…” Further, older adults with dual sensory impairment (DSI; hearing and vision impairment) perceive greater difficulty and worse outcomes than those with either vision or hearing loss. Reportedly, 12% of the population has vision-only loss, 13% have hearing-only loss, and 8% have DSI (15).
Unfortunately, healthcare systems do not have a defined pathway whereby patients at risk for MCI can be identified and educated regarding risk factor management. Primary care physicians are burdened with time and resource limitations. Specialists such as neurologists and psychiatrists generally assume care for patients during later, less-modifiable stages of dementia.
Advertisement
As such, clinics who regularly manage patients with primary sensory — vision and hearing — deficits represent a unique setting in which to identify and optimize risk factors. This model is gaining traction globally with 1 in 5 optometry clinics in the UK offering hearing care. Vision and hearing specialists have a high concentration of patients who are at risk for MCI, and these professionals deploy interventions that are known to alter the trajectory of dementia development. By combining services in the same location, the sensory clinic allows hearing and vision specialists to identify at-risk patients, optimize risk factors where appropriate and make referrals when needed.
Integrating audiology into an optometry clinic requires skilled professionals using best practices and thoughtful collaboration. Global demographic shifts indicate a rapid increase in the percentage of older adults. The overlap of older people with hearing, vision, and cognitive issues in isolation or in-tandem is significant.
Sensory-based clinics offer a pragmatic option for professionals and patients regarding sensory and cognitive health. By combining services in one location, sensory-based clinics can maximize synergies for professionals and convenience for patients.
REFERENCES:
(1) Alzheimer’s Association (2021): Alzheimer’s Disease Facts and Figures (March 23, 2021). The Journal of the Alzheimer’s Association. See here.
(2) Nichols, Vos, Murray et al (2022): Estimation of the global prevalence of dementia in 2019 and forecasted prevalence in 2050: an analysis for the Global Burden of Disease Study 2019. Published in The Lancet Public Health, January 2022. See here.
(3) Manly J., Jones RN., Langa KM., Ryan LH., Levine DA., McCammon R., Heeringa SG., Weir D. (2022): Estimating the Prevalence of Dementia and Mild Cognitive Impairment in the US: The 2016 Health and Retirement Study Harmonized Cognitive Assessment Protocol Project. JAMA Neurol. 2022 Dec 1;79(12):1242-1249. doi: 10.1001/jamaneurol.2022.3543. PMID: 36279130; PMCID: PMC9593315.
(4) Petersen, RC. (2016): Mild Cognitive Impairment. PMC 5390929 Continuum Review Article. Apr;22(2 Dementia):404-18. doi: 10.1212/CON.0000000000000313. PMID: 27042901; PMCID: PMC5390929.
(5) Wolk, DA., Rabinovici, GD., Dickerson, BC. (2023): A Step Forward in the Fight Against Dementia – Are We There Yet? JAMA Neurology 80(5): 429-430. doi:10.1001/jamaneurol.2023.0123
(6) Herper, M., & DeAngelis, A. (2022). See here.
(7) Peracino A (2014): Hearing loss and dementia in the aging population. Audiol Neurotol. 2014;19(suppl 1):6–9.
(8) Livingston G, Huntley J, Sommerlad A, Ames D, Ballard C, Banerjee S, Brayne C, Burns A, Cohen-Mansfield J, Cooper C, Costafreda SG, Dias A, Fox N, Gitlin LN, Howard R, Kales HC, Kivimäki M, Larson EB, Ogunniyi A, Orgeta V, Ritchie K, Rockwood K, Sampson EL, Samus Q, Schneider LS, Selbæk G, Teri L, Mukadam N. Dementia prevention, intervention, and care: 2020 report of the Lancet Commission. Lancet. 2020 Aug 8;396(10248):413-446. doi: 10.1016/S0140-6736(20)30367-6. Epub 2020 Jul 30. PMID: 32738937; PMCID: PMC7392084.
(9) Spierer, O., Fischer, N., Barak, A., & Belkin, M. (2016). Correlation Between Vision and Cognitive Function in the Elderly: A Cross-Sectional Study. Medicine, 95(3), e2423. See here.
(10)Zheng DD, Swenor BK, Christ SL, West SK, Lam BL, Lee DJ. Longitudinal Associations Between Visual Impairment and Cognitive Functioning: The Salisbury Eye Evaluation Study. JAMA Ophthalmoly. 2018;136(9):989–995. doi:10.1001/jamaophthalmol.2018.2493
(11)Vu, T., Fenwick, E., Gan, A. (2020). The Bidirectional Relationship Between Vision and Cognition: A Systematic Review and Meta-Analysis. Ophthalmology. Retrieved from here.
(12)Lin FR, Metter EJ, O’Brien RJ, Resnick SM, Zonderman AB, Ferrucci L. Hearing loss and incident dementia. Arch Neurol. 2011 Feb;68(2):214-20. doi: 10.1001/archneurol.2010.362. PMID: 21320988; PMCID: PMC3277836.
(13)Beck, DL. & Grisel, JJ (2022): Cognitive screenings in otolaryngology? The time has come. Journal of Otolaryngology ENT Research (JOENTR). 14(2). See here.
(14)Jiang, Mishra, Shrestha et al. (2023): The Lancet Public Health. April 13. Open Access. See here.
(15)Shakarchi AF, Assi L, Ehrlich JR, Deal JA, Reed NS, Swenor BK. Dual Sensory Impairment and Perceived Everyday Discrimination in the United States. JAMA Ophthalmol. 2020;138(12):1227–1233. doi:10.1001/jamaophthalmol.2020.3982
Advertisement