[Time perception in organically healthy and brain damaged subjects].

The aims of this study were to investigate whether brain lesions are associated with an impairment of time judgement and whether there is any relationship between alterations of time experience and the side and localization of brain lesions. References were made to the literature dealing with different definitions of the concept of time and the notions derived from time as a categorial entity, such as time experience, time perception and time awareness. To begin with, the philosophical and psychological approach was considered. There upon definitions as given by the natural sciences, conceptual classifications, phenomenological investigations as well as psychopathological considerations were analysed. Furthermore, the literature on disorders of time judgement was reviewed against the background of alterations of time experience in patients with brain lesions. In the present study patients with definite single brain lesions were examined and compared with a group of normal subjects. Three methods for testing time judgement (method of production, method of reproduction and time estimation) were applied to each subject. The results showed that in a substantial proportion of brain-damaged patients a subjective impression of changes in the rate at which time passed was reported, mostly in form of an apparent slowing down. No difference could be demonstrated between left or right cerebral lesions or between different localizations within one hemisphere. On the testing for objective time judgement the brain-damaged patients showed a tendency to under-or overestimation of time intervals, often exceeding the pre-established normal boundaries by far. We observed a certain "vulnerability" of the right hemisphere on the tasks for time judgement, especially in the case of right-sided parieto-occipital lesions.