To investigate the presence, nature and direction of the daily temporal association between depressive symptoms, cognitive performance and sleep in older individuals.

Single-subject study design in eight older adults with cognitive impairments and depressive symptoms.

For 63 consecutive days, depressive symptoms, working memory performance and night-time sleep duration were daily assessed with an electronic diary and actigraphy. The temporal associations of depressive symptoms, working memory and total sleep time were evaluated for each participant separately with time-series analysis (vector autoregressive modeling).

For seven out of eight participants we found a temporal association between depressive symptoms and/or sleep and/or working memory performance. More depressive symptoms were preceded by longer sleep duration in one person (r = 0.39; p < .001), by longer or shorter sleep duration than usual in one other person (B = 0.49; p < .001), by worse working memory in one person (B = −0.45; p = .007), and by better working memory performance in one other person (B = 0.35; p = .009). Worse working memory performance was preceded by longer sleep duration (r = −.35; p = .005) in one person, by shorter or longer sleep duration in three other persons (B = −0.76; p = .005, B = −0.61; p < .001; B = −0.34; p = .002), and by more depressive symptoms in one person (B = −0.25; p = .009).

The presence, nature and direction of the temporal associations between depressive symptoms, cognitive performance and sleep differed between individuals. Knowledge of personal temporal associations may be valuable for the development of personalized intervention strategies in order to maintain their health, quality of life, functional outcomes and independence.

Neurodegenerative diseases (NDDs), such as Alzheimer’s disease, frontotemporal dementia, dementia with Lewy bodies, and Huntington’s disease, inevitably lead to impairments in higher-order cognitive functions, including the perception of emotional cues and decision-making behavior. Such impairments are likely to cause risky daily life behavior, for instance, in traffic. Impaired recognition of emotional expressions, such as fear, is considered a marker of impaired experience of emotions. Lower fear experience can, in turn, be related to risk-taking behavior. The aim of our study was to investigate whether impaired emotion recognition in patients with NDD is indeed related to unsafe decision-making in risky everyday life situations, which has not been investigated yet.

Fifty-one patients with an NDD were included. Emotion recognition was measured with the Facial Expressions of Emotions: Stimuli and Test (FEEST). Risk-taking behavior was measured with driving simulator scenarios and the Action Selection Test (AST). Data from matched healthy controls were used: FEEST (n = 182), AST (n = 36), and driving simulator (n = 18).

Compared to healthy controls, patients showed significantly worse emotion recognition, particularly of anger, disgust, fear, and sadness. Furthermore, patients took significantly more risks in the driving simulator rides and the AST. Only poor recognition of fear was related to a higher amount of risky decisions in situations involving a direct danger.

To determine whether patients with an NDD are still fit to drive, it is crucial to assess their ability to make safe decisions. Measuring emotion recognition may be a valuable contribution to this judgment.