Lateralized visual hallucinations: an analysis of affective valence

Visual formaesthesias (hallucinations) are a common symptom of neurological insult. Research on emotional valances and the laterality of emotional valence extends to clinical populations experiencing visual hallucinations. The purpose of this project was to evaluate the relationship of reported hemispace of visual formaesthesia and associated emotional valence. Based on current literature exploring asymmetries in the processing of emotional valence, it was predicted that right visual formaesthesias would be predominantly associated with positive emotion and that left visual formaesthesias would largely be associated with negative emotion. Review of archival data on 150 neuropsychological patients from a rehabilitation unit in a tertiary care regional medical center resulted in 25 men and women, ages 25 to 93, endorsing visual formaesthesia upon neuropsychological interview. Analysis of variance results indicate the associated affective valence of the visual formaesthesia is a function of location, F(1, 24) = 8.33, p < .008. Additionally, the majority (84%) of sensory deficits detected were left-sided, regardless of the location of the formaesthesia. Patients specifically evidencing visual and tactile deficits had essentially exclusive left-sided deficits regardless of the location of the formaesthesia.