Dreaming and unilateral brain lesions: A multiple lesion case analysis.

Lesions causing cessation of dreaming are thought to be more frequently left hemispheric than right hemispheric. However, reports of this phenomenon have not excluded epileptic cases and have not reported handedness, etiology of the lesion, lesion location, comorbidity, gender, age, and so forth, on a case-by-case basis. Some authors were also concerned about aphasia being a cause of dream loss and its lateralization, but they never measured its impact statistically. The present investigation reviews cases of post lesion dream cessation that answered to strict criteria for testing hemispheric lateralization and the effect of aphasia on it. In the 31 subjects, left hemisphere lesions were significantly more frequent than right, as predicted, but the left hemisphere lesions were very often associated with aphasia. Nonaphasic cases of total dream loss had lesions equally often in the right and in the left hemisphere. It is proposed that aphasia deprives patients of a second dream-encoding system, which is important enough to induce amnesia of dream occurrence. (PsycINFO Database Record (c) 2010 APA, all rights reserved)