| Popis: |
Based on clinical, phenomenological and neurobiological observations, psychiatrists often report a deficit in time estimation in patients with schizophrenia. Cognitive models of time estimation in healthy subjects have been proposed and developed for approximately 30 years. The investigation of time perception is pertinent to the understanding of neurobiological and cognitive abnormalities in schizophrenia. Brain lesions and neuroimaging studies have shown that the critical brain structures engaged in time perception include the prefrontal and parietal lobes, thalamus, basal ganglia and cerebellum. These brain areas have been implicated in the physiopathology of schizophrenia in that there is impaired coordination of activity among these regions. Clinical and experimental date strongly suggest that patients with schizophrenia are less accurate in their ability to estimate time than healthy subjects. The specificity of these clinical and behavioral impairments is still in question. The aims of this article are to present an overview of the literature regarding time estimation and schizophrenia, to discuss specific issues related to how perceptual dysfunction in schizophrenia may lead to abnormalities in time perception, and to propose new perspectives towards an integrative approach between phenomenology and neuroscience.We present a review of the literature describing the current theory in the field of time perception, which is supported by a connectionist model, postulating that temporal judgment is based upon a pacemaker-counter device that depends mostly upon memory and attentional resources. The pacemaker emits pulses that are accumulated in a counter, and the number of pulses determines the perceived length of an interval. Patients with schizophrenia are known to display attentional and memory dysfunctions. Moreover, dopamine regulation mechanisms are involved in both the temporal perception and schizophrenia.It is still unclear if temporal impairments in schizophrenia are related to a specific disturbance in central temporal processes or are due to certain cognitive problems, such as attentional and memory dysfunctions, or biological abnormalities. While psychopathological and phenomenological work strongly suggests that time perception disturbance may be the key or core symptom in schizophrenia, neuroscience studies have failed to do the same. The question of specificity of temporal perception impairments in schizophrenia remains contested. Neuroscience studies suggest that time symptoms in patients with schizophrenia are only secondary to thought disorders and primary cognitive impairments. This debate refers to the etiologic/organic versus psychogenesis/psychological dichotomy and may be over-taken.Clinical evidence associated with psychopathological, biological and cognitive theories strongly suggests that patients with schizophrenia have a deficit in time perception. Discrimination and reproduction of durations have been found to be constantly impaired and disorganized. There is still much work to be done to identify the exact sources of variability in temporal judgments in schizophrenia, and the study of developmental course of time perception could be an interesting route. Regardless of the role of temporal deficits in the pathogenesis of schizophrenia (as a general cognitive disorder or a core role), clinical and phenomenological data encourage us to conduct further studies, especially in the field of developmental psychology. |
