Eiichi Tanabe

Significant linkage to chromosome 22q for exploratory eye movement dysfunction in schizophrenia

A genome‐wide scan for a locus responsible for exploratory eye movement (EEM), which is quantitative and can be disturbed in association with schizophrenia, was performed. A 10‐cM resolution genome‐wide linkage analysis of the EEM disturbance with 358 highly polymorphic microsatellite markers in 38 nuclear families with 122 members (38 probands, 47 sibs, and 37 parents) including 58 sib‐pairs yielded the suggestive linkage to the GCT10C10 marker on chromosome 22q11.2 (LOD = 2.48). Dense mapping with additional markers around the GCT10C10 marker yielded evidence for significant linkage between EEM disturbance and markers D22S429 and D22S310 on chromosome 22q12.1 (LOD score of 4.63) with suggestive evidence for the chromosome region 22q11.2–q12.1. Our findings suggest that a relatively small number of loci may control the schizophrenia‐related quantitative EEM trait. We believe that identifying gene(s) on chromosome 22q associated with the EEM phenotype may forward our understanding of the etiology of schizophrenia.

Impairment of exploratory eye movement in schizophrenia patients and their siblings

Aims:  Previous family, adoption and twin studies of schizophrenia have shown that genetic factors contribute significantly to the risk of schizophrenia. The aim of the present study was therefore to investigate whether exploratory eye movement (EEM) abnormalities are related to the genetic markers linked to schizophrenia.

Age at onset of schizophrenia: gender differences and influence of temporal socioeconomic change.

This study was undertaken to examine whether males develop schizophrenia at a younger age than females, and whether temporal socioeconomic change affects the age at onset of schizophrenia. The subjects were 848 ICD‐9 schizophrenics who were admitted to Nihon University Hospital, Tokyo, Japan, during the period of 1955–64 (n = 468 (214 males and 254 females), group A) or during the period of 1982–91 (n = 380 (220 males and 160 females), group B). Schizophrenic males showed an earlier age at onset than schizophrenic females. However, the mean age at onset of schizophrenia did not differ significantly between group A and group B. These results indicate that the gender difference in age at onset of schizophrenia has not been influenced by temporal socioeconomic change.

Patients with systemic lupus erythematosus show a normal responsive search score in exploratory eye movement analysis: comparison with schizophrenia

Objective: To assess whether a difference in psychiatric vulnerability exists between patients with systemic lupus erythematosus (SLE) and those with schizophrenia. Methods: Twenty women with SLE underwent exploratory eye movement analysis, and a responsive search score (RSS) was obtained, two months after the onset of the disease. Fifteen women with schizophrenia in remission also underwent this analysis. Exploratory eye movement was recorded by an eye mark recorder, which detects corneal reflection of infrared light. The number of eye fixations (instance of more than 0.2 seconds of eye fixation time) was recorded, and the RSS was calculated from eye fixation analysis. Results: Mean (SD) RSS differed significantly between patients with SLE and those with schizophrenia (9.85 (1.87) v 7.27 (1.58) points, respectively, p<0.0001), whereas no difference in mean RSS was found between patients with SLE and 19 normal women. No difference in mean RSS was found between patients with active SLE and those with inactive SLE (9.51 (1.87) v 10.0 (1.77) points). Conclusion: The psychiatric vulnerability in patients with SLE, measured by the RSS, differs from that in patients with schizophrenia.

Random number generation evaluation in patients with systemic lupus erythematosus indicates a heterogeneous nature of central nervous system vulnerability

Objective: To evaluate the vulnerability of the central nervous system (CNS) in patients with systemic lupus erythematosus (SLE). Methods: Forty‐eight patients with SLE, 58 with schizophrenia in remission and 39 healthy controls were enrolled in the study. Patients vocally generated 100 numbers in a random fashion, using numbers 0 to 9, and were evaluated with seriality scores. Patients with SLE were subgrouped according to differences in the presence of Raynauds phenomenon, anti‐phospholipid antibody, lupus activity, and a history of neuropsychiatric (NP) lupus, and these patients were also evaluated by comparison with their counterparts. Results: In general, patients with SLE showed lower seriality scores than patients with schizophrenia, and higher seriality scores than normal controls. The scores of the patients with a history of NP lupus matched those with schizophrenia, and the scores of never having NP lupus matched those of the healthy controls. Conclusions: CNS vulnerability may be prolonged in patients who have a history of NP lupus even when they appear to be in normal NP status. The damage in random number generation (RNG) observed in patients with a history of NP lupus seemed equal to that found in those with schizophrenia, whereas those patients never having NP lupus appeared to be equal to the controls. The current study suggests a heterogeneous nature of SLE and prolonged damage, especially in CNS vulnerability, when evaluating with RNG.

Relationship between exploratory eye movement, P300, and reaction time in schizophrenia.

Aims:  Exploratory eye movement (EEM), P300 and reaction time (RT) tests may relate to the important parts of information processing in the human brain. Therefore the aim of the present study was to compare EEM, P300 and RT test data in schizophrenic and normal control groups to investigate whether schizophrenic patients have information processing abnormalities. In addition, the potential correspondence between the three tests was examined in order to investigate the information processing dysfunctions seen in schizophrenic patients.

Analysis of exploratory eye movement in a patient with lupus psychosis

The psychiatric and cognitive condition of a patient with lupus psychosis was evaluated. Using a device that detects the corneal reflection of infrared light, the patterns of eye tracking movements were recorded before the onset of lupus psychosis, after remission, and again 1 year later. Electroencephalographic findings and cerebrospinal fluid levels of both interferon α and interleukin-6 were also obtained longitudinally. Electroencephalographic findings and clinical signs were correlated to the levels of interferon α in cerebrospinal fluid. Analysis of exploratory eye movements revealed marked decreases in the number of eye fixations, mean eye-scanning length and total eye-scanning length. Even though the lupus psychosis resolved and the electroencephalographic findings became normal, the eye movement patterns showed remaining deterioration. It was concluded that analysis of exploratory eye movements in patients with systemic lupus erythematosus may be useful in diagnosing lupus psychosis, and may also present a diagnostic clue to subclinical lupus psychosis.

Prolonged polysomnography in a case with recurrent hypersomnia

Abstract An 18‐year‐old male patient with recurrent hypersomnia (RH) was evaluated using prolonged polysomnography (PSG). During symptomatic period (SMP), the patient showed both ‘dissociated stage REM’ (DREM), REM sleep without muscle atonia and ‘dissociated stage 1’ (DSt‐1), and stage 1 sleep with rapid eye movement. These stages were observed in the morning or following daytime record. They decreased during asymptomatic period (ASMP). It has been said that RH is caused by dysfunction of the hypothalamus and midbrain limbic system. The present result suggests also that RH involves dysfunction of the brain stem.