The association of gustatory dysfunction, olfactory dysfunction, and cognition in older adults.

Background: The association of gustatory dysfunction (GD) with quality of life (QOL) and cognition in older adults is understudied. Our objective was to study the prevalence of GD in the community and explore impacts and associated factors.

Methods: A prospective, multi-institutional, pre-corona virus disease (COVID) cohort of adults aged 50 years and older had smell and taste testing using "Sniffin' Sticks" (TDI) and "Taste Strips." The impact of GD on mood, QOL, and social interaction was assessed through visual analog scales. Subjects completed the Questionnaire of Olfactory Disorders, Patient Health Questionnaire 9, Mini-Mental State Examination (MMSE), Montreal Cognitive Assessment, and the DeJong scale of loneliness.

Results: A total of 48 patients, average age of 54.7 years, were enrolled. Thirty-two percent experienced GD on taste strips, and 62% experienced olfactory dysfunction (OD) on TDI. Almost 30% (29.5%) had both GD and OD. GD and OD correlated with worsened cognitive function on MMSE (r = 0.392 and 0.05, p = 0.018 and 0.003). Subjects with both GD and OD had worse MMSE than either alone (p = 0.003). Dry mouth and difficult chewing correlated with GD (r = -0.37 and -0.31, p = 0.10 and 0.37). Self-reported GD and OD were correlated (r = 0.46, p = 0.001), as were psychophysical GD and OD (r = 0.394, p = 0.008). GD did not correlate with other metrics.

Conclusion: Thirty-two percent of subjects experienced GD on psychophysical testing, yet most are unaware without impacts on daily life. However, GD correlates with worsened cognitive function. Taste testing may play a role in screening of neurocognitive decline, and multisensory dysfunction may indicate of worsened cognitive states.