Objective: 

Disturbances in emotional processing are a typical feature of dementia and mild cognitive impairments in elderly patients. These disturbances have been attributed to age-related changes in the circadian clock. This report aims at studying changes in emotional responses using the Self Assessment Manikin (SAM) ratings of the International Affective Picture System (IAPS) before and after exposure to bright light used to entrain the biological clock in institutionalized subjects with mild cognitive impairments

Methods: 

Six elderly (mean age 75) institutionalized subjects of both sexes with mild cognitive impairment were studied during two weeks. The first week served to set the baseline level. On the second week, each subject was submitted to 90 min of bright light. Before and after the treatment, the subjects' emotional state was evaluated using 30 pictures selected from the IAPS. Of them, 13 were pleasant, 8 neutral, and 10 unpleasant. Each picture was shown together with the 9-point SAM scale. The subjects rated their response to each picture according to a three dimensional scale: valence (pleasantness), arousal (activation level) and dominance (capacity to modify the state).

Results: 

The exposure to bright light caused modifications in the valence and the arousal. Regarding valence, the pleasantness and unpleasentness rating decreased and increased respectively. The arousal changed in the same way, increasing the activation caused by the unpleasant pictures and decreasing for pleasant ones. The dominance remained without changes.

Conclusions: 

The bright light therapy changed the emotional valence and arousal of the subjects at the levels reported in the bibliography for young subjects.