Insomnia impact on sleepiness and vigilance performance differs by age

By Sara Freeman, medwireNews Reporter

medwireNews: Insomnia may affect people in different ways as they age, results of a prospective, 10-year study suggest.

“Our results suggest that the consequences of insomnia vary by age group, and that there may be a mechanism associated with the aging process that could amplify the impact of insomnia on vigilance performance yet lessen perceived sleepiness in older adults,” report Hyun Kim (Korean University Ansan Hospital, Republic of Korea) and co-workers in the Journal of Psychosomatic Research.

Daytime sleepiness assessed by the Epworth Sleepiness Scale (ESS) significantly varied by the degree of insomnia in middle-aged (49–64 years) individuals, but had no affect on their psychomotor vigilance task (PVT) performance.

Conversely, insomnia had little impact on older adults’ (65–79 years) daytime sleepiness but did significantly reduce their PVT performance. The latter involved pushing a button in response to a visual stimulus on a screen.

Data on 1657 middle-aged (mean age 55 years) and 405 older (mean age 70 years) adults who were enrolled in the Korean Genome and Epidemiology Study (KoGES) showed that there was a nonsignificant trend for more episodes of insomnia in older adults (1.9 versus 1.7).

Among middle-aged participants, the rates of no insomnia, single-episode insomnia, and persistent insomnia (in remission or ongoing) were 46%, 21%, and 33%, respectively, with corresponding figures in older adults of 38%, 23%, and 39%.

Looking only at those with persistent ongoing insomnia (19% of middle-aged and 21% of older adults), Kim et al found older adults were significantly more likely to have difficulty initiating (62 vs 44%) and maintaining sleep (49 vs 36%) than middle-aged adults, and significantly less likely to have non-restorative sleep (58 vs 71%).

Mean ESS scores in middle-aged adults were significantly higher in those with than without insomnia, at 4.74 in those without insomnia versus 5.26 in those with single-episode insomnia, 5.86 in those with persistent insomnia in remission, and 5.91 in those with persistent ongoing insomnia.

No significant association was seen between sleepiness and insomnia in the older adults, but insomnia did impact on PVT results in this group. The mean reciprocal response times were significantly slower in those with than without insomnia, at 3.59 ms in those without insomnia versus 3.42 ms, 3.41, and 3.34 for those with single-episode insomnia, persistent insomnia in remission, and persistent ongoing insomnia, respectively.

“Further research with advanced brain imaging techniques may facilitate our understanding of the role of aging in insomnia and daytime functioning,” the researchers conclude, as well as the mechanisms underlying age- and insomnia-related changes in cognitive performance.

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