ABSTRACT
Laterality of thumb opposition and handedness were determined in three groups of subjects: patients with Huntington's chorea (n = 18), asymptomatic offspring of patients (n = 40), and asymptomatic siblings of patients over 50 years of age termed 'escapees' (n = 17). 100% of patients and 55% of young at-risk offspring had crossed laterality of thumb opposition and handedness. Only 2 (11.8%) of the 'escapees' had crossed laterality. Crossed laterality may be associated with symptomatic presymptomatic Huntington's chorea.
Subject(s)
Functional Laterality , Genetic Testing/methods , Huntington Disease/genetics , Adolescent , Adult , Age Factors , Aged , Child , Female , Genes, Dominant , Genetic Counseling , Humans , Male , Methods , Middle Aged , Risk , Thumb/physiologyABSTRACT
Tests of lateral asymmetry in hand preference and superiority in thumb opposition rotation (opposing the thumb's pulp surface to that of the little finger) have been applied to bipolar and unipolar affective patients in an attempt to evaluate the effectiveness of these tests in differentiating the bipolar and unipolar patient populations. Two comparison samples were also tested: nonpsychotic central nervous system (CNS) disease patients, and normal controls. The normals divided almost evenly into pure dominance (e.g., right-handed, and superior right thumb opposition) and cross-dominance (e.g., right-handed, but superior left thumb opposition). All but one of the CNS disease patients were cross-dominant; the bipolars were predominantly pure dominant; while the unipolars, in contrast to the pure dominant bipolars, were in the majority cross-dominant. This result is consistent with the view that there are two types of affective disorder, bipolar manic-depressive and unipolar depressive illness.
Subject(s)
Bipolar Disorder/diagnosis , Depression/diagnosis , Functional Laterality , Central Nervous System Diseases/diagnosis , Diagnosis, Differential , Dominance, Cerebral , Female , Humans , Male , Middle Aged , Thumb/physiologyABSTRACT
Three factors in combination cause diseases of the central nervous system (CNS): specific etiological agent, physical stress and a general constitutional predisposition to CNS diseases. Research has tended to focus on the first to the disregard of the second and third factors. A newly developed test of functional body asymmetry, however, may have application to the elucidation of the role of physical stress and the constitutional predisposition to CNS diseases. In the present study, neurophysioligcal tests of lateral asymmetry in hand preference and thumb opposition rotation divide the normal population equally into a pure dominant group and a cross-dominant group. Neurological interviews with each group show cross-dominant normal subjects to be more vulnerable to physical stress factors such as overexertion and sleep disturbance. In a previous sutdy applying the same tests, patients with manifest primary diseases of the CNS such as parkinsonism showed cross-dominance in more than 90% of cases. These results with cross-dominant normals and CNS disease patients suggest that cross-dominance indicates a constitutional predisposition to CNS diseases. They also suggest that cross-dominant normal individuals are vulnerable to pysical over-exertion and the specific etiological agent responsible for a distinct CNS syndrome. As far as temporal order is concerned, since it is present in 50% of the normal population, cross-dominant laterality would appear to be a condition prior to any disease process rather than a consequence of CNS disease.
Subject(s)
Central Nervous System Diseases/etiology , Disease Susceptibility , Functional Laterality , Adolescent , Adult , Central Nervous System Diseases/prevention & control , Disease Susceptibility/diagnosis , Fatigue/complications , Humans , Physical Exertion , Sleep Wake Disorders/complications , Stress, PhysiologicalABSTRACT
Hand preference and the performance of thumb-to-finger opposition by the right and left hands were tested in four samples: manic-depressives, schizophrenics, nonpsychotic patients with diseases of the central nervous system and normal control subjects. The schizophrenics and manic-depressives both showed significantly more pure dominance (e.g. right-handed, and superior right thumb opposition) than the normal controls, while the nonpsychotic patients with diseases of the central nervous system showed significantly more cross-dominance (e.g. right-handed, but superior left thumb opposition) than the normal control subjects.
