Sensory-specific impairment among older people. An investigation using both sensory thresholds and subjective measures across the five senses

Abstract

Age-related sensory impairment is a slow and gradual progress, which affects multiple modalities. Two contradictory hypotheses exist about the age-related decline of sensory thresholds. The common factor theory assumes one underlying factor—which accounts for the loss of several sensory modalities simultaneously—and the specific factor theory predicts that the sensory decline is uncorrelated between different modalities. In this study, we aimed to explore whether (i) there is a common factor of sensory thresholds in older people, (ii) older people assume that sensory decline in one modality also affects other modalities, (iii) there is a relation between sensory threshold and the subjective assessment of sensory function. This was accomplished by collecting both threshold measures and self-reported ratings for smell, hearing, taste, vision, and touch function in a group of 104 older people (mean age: 67.2 years; SD: 9.85; range: 50–100 years). Results indicated that there was no common factor of sensory thresholds, hence an impairment in one modality did not necessarily imply a shortfall in other modalities. In contrast, our results suggested one or two common factor(s) for the participants’ ratings. Participants who reported a diminished function in one sense tended to generalize this rating to the other senses as well. The correspondence between subjective ratings and sensory thresholds was relatively good for vision and audition, although no correlations were observed for the other domains. These findings have implications for clinicians, suggesting that subjective measures should be combined with sensory threshold measurements when evaluating sensory dysfunction. Also, these data convey a positive message for older people and their physicians by showing that loss in one sensory modality does not necessarily generalize to losses across all sensory modalities.

Bitter, Sweet, Salty, Sour and Umami Taste Perception Decreases with Age: Sex-Specific Analysis, Modulation by Genetic Variants and Taste-Preference Associations in 18 to 80 Year-Old Subjects

“…In the review undertaken on this topic by Sergi, et al [ 58 ], the authors concluded that there was only sufficient evidence to conclude an age-related decrease in the perception of bitter (PROP) and sour tastes and that more studies were required to clearly conclude the decrease in the perception of other tastes. Our study, therefore, is useful in that it provides more specific data on quantification and better characterization of the decrease in the perception of the different tastes with age; other studies have analysed fewer taste qualities [ 59 , 60 , 61 , 62 , 63 , 64 , 65 ] have focused on a shorter age range [ 64 , 65 ], have studied children and their mothers [ 65 ]; or when the five taste qualities have been studied, their sample size has been very small [ 38 , 58 , 66 ]. Therefore, the results of these individual studies regarding the association between taste perception qualities and age have been heterogeneous.…”

Thermal Sensation in Older People, with and without Dementia, Living in Residential Care: New Assessment Approaches Using Infrared Thermography

“…The possibility that the older person's thermal perception of the environment is 'blunted' is consistent with the biological consequences of ageing on thermogenesis and decline in thermosensitivity [35]. This blunting of thermal sensation can occur similarly as in other types of sensory perception loss wih age [36];…”

Thermal Sensation in Older People with and without Dementia Living in Residential Care: New Assessment Approaches to Thermal Comfort Using Infrared Thermography

“…The possibility that the older person’s thermal perception of the environment is ‘blunted’ is consistent with the biological consequences of ageing on thermogenesis and decline in thermosensitivity [ 35 ]. This blunting of thermal sensation can occur similarly as in other types of sensory perception loss with age [ 36 ]; hearing, vision, taste and smell being additional examples. We have observed features of thermal blunting in the older residents, particularly those with dementia where we observed residents with low extremity (digit) temperatures corresponding to ‘cold hands’ reporting thermal sensation as neutral (or comfortable) even with obvious visual ‘thermal amputation’ on the thermal map and even where environmental temperature was within the thermoneutral range [ 37 , 38 ].…”