[Laterality in schizophrenics and their relatives--a trait marker?].

The authors present the results of investigations of a developmental deviation in the functional symmetry of paired motor and sensory organs (laterality) in a group of 160 schizophrenics and 126 healthy relatives of these patients (88 parents, 38 siblings). As a control group served 754 healthy subjects (Prague population). The phenotype of motor laterality (hands and feet) and sensory laterality (eyes and ears) was assessed by diagnostic tests for assessment of laterality. For assessment of the lateral cerebral dominance the torque test was used. For mathematical processing analysis of multidimensional frequency tables by means of Cox'models for binary data was used. The distribution of motor laterality of the upper extremities in schizophrenics is almost reverse, as compared with the distribution in the population. Defined dextrolaterality is lower in patients (P less than 0.0001) and little defined dextrolaterality is, on the other hand, significantly higher (P less than 0.0001). For schizophrenics ambiguousness (ambidextrity) is typical, being twice as frequent as in the healthy population (P less than 0.0001). In parents and siblings similar changes of laterality of the hand were found, in particular as regards defined and little defined dextrolaterality but not as far as ambidexterity is concerned. As regards left-handedness in patients and their relatives no changes were recorded. Incomplete lateralization of functions of the left hemisphere and abnormal cerebral dominance resp. were confirmed by the torque test in a large proportion of schizophrenics and to a smaller extent also in their relatives. Marked preference for the right side (score 0) which was recorded in 47.6% controls was found only in 15.8% schizophrenics, 23.9% parents and 31.4% siblings.(ABSTRACT TRUNCATED AT 250 WORDS)