Klaus-Malte Flechtner

Basic parameters of saccadic eye movements – differences between unmedicated schizophrenia and affective disorder patients

Background Smooth pursuit eye movement (SPEM) dysfunctions are considered a biological marker for schizophrenia and have been studied widely. In contrast, saccadic eye movements have received less attention, although disturbances have been described previously. Basic neurophysiologic parameters of saccades in schizophrenics, especially in unmedicated patients, have not been studied extensively. Methods Saccadic eye movements of 38 unmedicated schizophrenic patients, 32 patients with major depression and 42 non-psychiatric controls were examined using high-resolution infrared oculography. Two large-amplitude saccadic tasks were presented. The groups were compared on peak velocity, reaction time and accuracy. Results Peak velocity was significantly increased in schizophrenic patients. Depressive patients had a significantly longer reaction time. Both patient groups needed more corrective saccades to reach the target than controls. Conclusions Peak velocity distinguishes unmedicated schizophrenic patients from depressive patients and normal controls. This could be explained by deficits of the prefrontal cortex in the inhibitory control of saccades. Our findings suggest that schizophrenia affects not only SPEM but also saccadic eye movements.

Mixed connective tissue disease: recurrent episodes of optic neuropathy and transverse myelopathy. Successful treatment with plasmapheresis

Severe neuropsychiatric manifestations in mixed connective tissue disease (MCTD) are thought to be quite rare. We report an unusual case of MCTD with recurrent optic neuropathy and transverse myelopathy suggestive of a relapsing-remitting demyelinating disorder. Symptoms responded dramatically to a treatment with plasmapheresis and immunosuppressive medication.

Increased blink rates in schizophrenics. Influences of neuroleptics and psychopathology

During a standardized visuomotor task, eye blinking, a possible parameter of central dopaminergic activity, was studied in 18 previously medicated and eight drug-naive schizophrenic in-patients in the acute state and during remission. Whereas schizophrenics executed the visuomotor task with the same precision as age- and sex-matched normal control subjects did, the mean blink rate was increased in both schizophrenic groups. During neuroleptic treatment, the mean blink rate was reduced only in the group of drug-naive patients, but not in the previously neuroleptic treated schizophrenics. This varying blinking activity is discussed with respect to the development of neuroleptic tolerance and influence of psychopathology.

Smooth pursuit eye movements of patients with schizophrenia and affective disorder during clinical treatment

Background Smooth pursuit eye movement dysfunctions are considered a biological indicator for vulnerability to schizophrenia. This study examines test-retest stability of specific eye movement variables such as velocity gain and different saccadic categories. Methods Smooth pursuit eye movements of 27 schizophrenic patients and 30 patients with major depression were examined three times during clinical treatment using high-resolution infrared oculography. Forty-one normal controls were retested after four weeks. Results Intraclass correlation coefficients as a measure for retest-stability were highly significant in each group for all time-points, except for anticipatory saccades in schizophrenics. No significant correlations were found between psychopathological status, neuroleptic medication and eye movement variables. Conclusions Our results indicate that the most important measures of eye tracking performance in psychiatric patients are not significantly influenced by neuroleptic medication or clinical state and are stable across time.

Subthreshold symptoms and vulnerability indicators (e.g., eye tracking dysfunction) in schizophrenia.

Subthreshold symptoms in schizophrenia can be prodromal signs of a psychotic relapse. In people without schizophrenia, similar symptoms may indicate the presence of disorders termed schizophrenia spectrum disorders. Subthreshold schizophrenia-like symptoms may indicate a genetically transmitted higher proneness to schizophrenia. Such a higher liability to develop schizophrenia is ascertained on a symptom level. In genetic studies, asymptomatic members of a pedigree are therefore classified as unaffected although they may possess the genes in question. On a biological level, eye tracking dysfunction has been shown to fulfill certain criteria for a vulnerability indicator and therefore promises to offer more information on genetically transmitted proneness to schizophrenia even in people without psychopathological symptoms. Subthreshold symptoms may warrant treatment. The database for prophylactic treatment in populations at high risk, especially those without symptoms, is currently very small.

Lithium effect on smooth pursuit eye movements of healthy volunteers

Smooth pursuit eye movement (SPEM) dysfunctions in major affective disorder patients have been reported to be associated with lithium treatment. We report that SPEM of 13 healthy volunteers, either taking lithium (n = 7) or placebo (n = 6), were not significantly impaired by lithium. This could point to a pathophysiologic difference between affective disorder patients and a normal population.

Alters- und Geschlechtseffekte auf langsame Augenfolgebewegungen, einen möglichen Vulnerabilitätsindikator für Schizophrenie

Storungen von langsamen Augenfolgebewegungen werden seit den 70er Jahren als genetisch determinierter Marker und moglicher Vulnerabilitatsindikator der Schizophrenie diskutiert (Holzman 1987, Clementz und Sweeney 1990). Voraussetzung fur einen solchen Indikator ist eine moglichst grose Spezifitat fur schizophrene Erkrankungen, wie vergleichende Studien zwischen verschiedenen Patientengruppen nahelegen. Allerdings sind auch bei depressiven Patienten Augenfolgebewegungsstorungen in ahnlichem Ausmas beschrieben worden (Abel et al. 1991, Friedman et al. 1992). Mogliche unabhangige Einflusgrosen, wie Alter und Geschlecht, wurden in bisherigen Untersuchungen zur Krankheitsspezifitat dieses Merkmals nur wenig berucksichtigt.

Die nosologische Spezifität und zeitliche Stabilität von Augenfolgebewegungsstörungen bei schizophrenen Patienten

Storungen der Augenfolgebewegungen (smooth pursuit eye movements, SPEM) gelten als vielversprechender Marker fur schizophrene Erkrankungen (Holzman 1987, Clementz und Sweeney 1990). Die Tauglichkeit einer Variablen als genetisch determinierter Trait-Marker ist an folgende Voraussetzungen geknupft: nosologische Spezifitat und zeitliche Stabilitat, gehauftes Vorkommen auch bei Familienangehorigen von Schizophrenen, einfache und reliable Messung. Trotz der Vielzahl publizierter Arbeiten zu SPEM-Storungen bei Schizophrenen existieren widerspruchliche Befunde hinsichtlich der nosologischen Spezifitat, daneben fehlen Untersuchungen zur zeitlichen Stabilitat des Merkmals. Zudem wurde in den meisten Arbeiten nur global von SPEM-Storungen ausgegangen, auf eine exakte Beschreibung anhand neurophysiologischer Kriterien jedoch verzichtet. Insbesondere in den fruhen Publikationen wurde die Gute von SPEM qualitativ meist uber eine funffach gestufte Skala (Shagass et al. 1974) bestimmt, wobei die Haufigkeit der in die Folgebewegungen eingelagerten schnellen Komponenten (Sakkaden) als Beurteilungskriterium diente.