Increasing evidence suggests that smooth pursuit eye movement (SPEM) dysfunction may serve as an endophenotype or genetic marker of schizophrenia. The authors tested SPEM and visual fixation (VF) in 31 patients with schizophrenia, 33 of their first-degree relatives, and 24 patients with major depressive disorder. A high rate of abnormal VF was found in schizophrenic patients and their first-degree relatives, but not in affective disorder patients with or without psychotic features. Rate of VF abnormality distinguished schizophrenic patients from acutely depressed mood disorder patients; SPEM did not. VF and SPEM performance correlated only moderately, suggesting that the pathophysiologies of these two eye movement abnormalities may be partially independent. Implications for identifying a schizophrenia endophenotype are discussed.
"A large number of studies have examined smooth pursuit eye movement function in the relatives of schizophrenia patients. The vast majority of studies confirmed the dysfunction in a proportion of the first-degree relatives of schizophrenia probands (Amador et al. 1995; Ettinger et al. 2004; Karoumi et al. 2001 for a review Thaker 2008). As described in the companion paper (Kattoulas et al. 2011), smooth eye pursuit is subserved by a wide and complex neuronal network of cortical and subcortical areas including the frontal eye fields, supplementary eye fields, intraparietal sulcus, precuneus, extrastriate areas (medial temporal cortex and medial superior temporal cortex) and the cingulate cortex (Berman et al. 1999; O'Driscoll et al. 2000; Ilg and Thier 2008; Sharpe 2008). "
[Show abstract][Hide abstract] ABSTRACT: Smooth pursuit eye movement dysfunction is considered to be a valid schizophrenia endophenotype. Recent studies have tried to refine the phenotype in order to identify the specific neurophysiological deficits associated with schizophrenia. We used a variation of the smooth eye pursuit paradigm, during which the moving target is occluded for a short period of time and subjects are asked to continue tracking. This is designed to isolate the predictive processes that drive the extraretinal signal, a process previously reported to be defective in schizophrenia patients as well as their healthy relatives. In the current study, we investigated the relationship between predictive pursuit performance indices and age, education, non-verbal IQ, schizotypy and state anxiety, depression in 795 young Greek military conscripts. State anxiety was related to better predictive pursuit performance (increase in residual pursuit gain), while disorganized schizotypy was related to deficient predictive pursuit performance (decreased residual gain). This effect was independent of the effect of disorganized schizotypy on other oculomotor functions supporting the hypothesis that predictive pursuit might be specifically affected in schizophrenia spectrum disorders and could be considered as a distinct oculomotor endophenotype.
Experimental Brain Research 12/2011; 215(3-4):219-26. DOI:10.1007/s00221-011-2888-4 · 2.04 Impact Factor
"Finally, it has been suggested that people with schizophrenia have a deficit in suppressing unwanted saccades compared to healthy subjects in an active visual fixation task    or in an active fixation task with increased inhibitory load, for example by adding distracting targets   . These data then suggest that EMD in the form of deficits in smooth eye pursuit, antisaccades and less so in active fixation could be potential endophenotypes for schizophrenia   . "
[Show abstract][Hide abstract] ABSTRACT: Measures of eye movement dysfunction have been considered as candidate endophenotypes for the study of genetic liability in schizophrenia. In this respect it is crucial to confirm a clinical state independentce of these measures. Twenty people with DSM-IV schizophrenia were assessed using a battery of oculomotor tasks in the acute phase of their disorder without being treated with antipsychotic medication and then again in the remission phase under treatment with antipsychotic medication. The saccade latency in the saccade task, the error rate and antisaccade latency in the antisaccade task, and the frequency of unwanted saccades in the active fixation task were stable in time both at the group level and within each individual, showing no relation to the significant improvement in different psychopathological dimensions of these patients. The root mean square error, gain and saccade frequency in the pursuit task were not stable over time, although again this instability was not related to the changes in psychopathological status of these patients. Finally, the saccade frequency in the active fixation task with distracters was not stable in time and was correlated with changes in specific dimensions of psychopathology. These results provide further evidence that saccade and smooth eye pursuit dysfunction measures are not affected by the substantial change in the clinical state of schizophrenia from the acute phase to remission, and strengthen the current view that they can be used as endophenotypes. On the other hand, active fixation might be state-dependent adding to the evidence against its use as a candidate endophenotype in schizophrenia.
European Psychiatry 11/2008; 24(1):17-26. DOI:10.1016/j.eurpsy.2008.08.003 · 3.44 Impact Factor
"Additionally, in schizophrenia patients smaller pupillary response and higher levels of perceptual inaccuracy were associated with clarity of conceptual thinking as assessed by WSUM6 (Minassian et al, 2004). Previous work indicates that visual deficits in schizophrenia may be associated with magnocellular dysfunction, resulting in a limited ability to achieve visual form recognition and perceptual closure (Amador et al., 1995; Doniger et al., 2001; Gabrovska et al., 2003). In particular, deficits in magnocellular functioning may impact the ability to identify and distinguish salient visual stimuli on RCS cards and organize them within the context in which they are embedded. "
[Show abstract][Hide abstract] ABSTRACT: Schizophrenia has been associated with deficits in visual perception and processing, but there is little information about their temporal development and stability. We assessed visual form perception using the Rorschach Comprehensive System (RCS) in 23 individuals at clinical high risk for psychosis, 15 individuals with recent onset schizophrenia (< or =2 years since onset), and 34 with chronic schizophrenia (> or =3 years since onset). All three groups demonstrated reduced conventional form perception (X+%), as compared with published norms, but did not differ significantly from one another. In contrast, the high-risk group had significantly better performance on an index of clarity of conceptual thinking (WSUM6) compared to the chronic schizophrenia patients, with the recent onset group scoring intermediate to the high-risk and chronic schizophrenia groups. The results suggest that individuals at clinical high risk for psychosis display substantial deficits in visual form perception prior to the onset of psychosis and that these deficits are comparable in severity to those observed in individuals with schizophrenia. Therefore, visual form perception deficits may constitute a trait-like risk factor for psychosis in high-risk individuals and may potentially serve as an endophenotype of risk for development of psychosis. Clarity of conceptual thinking was relatively preserved among high-risk patients, consistent with a relationship to disease expression, not risk. These deficits are discussed in the context of the putative neurobiological underpinnings of visual deficits and the developmental pathophysiology of psychosis in schizophrenia.
Schizophrenia Research 01/2008; 97(1-3):25-34. DOI:10.1016/j.schres.2007.08.022 · 3.92 Impact Factor
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