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Tactile memory test in schizophrenics and their first-degree relatives
187 VISUAL EVOKED POTENTIALS
AND SCHIZOPHRENIA
Roger Thomas Department of Psychological Medicine, University Medicine, Heath Park, Cardiff CF4 4XN, UK
of Wales College
of
Laterality effects to small bright stimuli in the left, central and right visual fields were investigated in both normal and schizophrenic subjects. This was done to test the hypothesis of defective interhemispheric transfer in schizophrenia. Normals showed earlier latency and larger amplitude evoked potentials over the directly stimulated hemisphere, and a smaller delayed response over the indirectly stimulated one, compatible with a possible transmission across the corpus callosum. This asymmetry of latency was lost in schizophrenic subjects even if they were free of medication. Possible interpretations may be related to recent work on agenesis of the corpus callosum and its association with schizophrenia.
IX c.
Neuropsychological
TACTILE TIVES
MEMORY
TEST
IN SCHIZOPHRENICS
M. Alda, M. Posmurova, Psychiatric
and other Related Tests
AND
THEIR
FIRST-DEGREE
RELA-
and P. Zvolsky
Research Unit, Charles University,
Prague, Czechoslovakia
On the basis of neuropsychological findings, various hypotheses on cerebral dysfunction in schizophrenia have been suggested: a dominant hemisphere dysfunction (61, both left hemisphere dysfunction and overactivation (41, a disruption in the system which balances the activity of the left and right hemispheres (31, and a fault in the interhemispheric transfer of information (2,7). One of the methods by means of which these disorders can be studied is the Tactile Memory Test (TMT) (Mika, unpublished) in which fingers on both hands touched simultaneously are to be remembered. This test allows not only the of the right and left hands, but also a study of a performance preference of the strategy of solution (51, (i.e., verbal - supposedly connected with dominant-hemisphere functions, and nonverbal, tactile - dependent on nondominant-hemisphere functions). Subjects for this study were 56 patients with an RDC diagnosis of schizophrenia, their 36 healthy parents and 19 healthy siblings, 54 nonpsychotic patients, mostly with psychosomatic complaints, and 57 healthy subjects. All the subjects were examined by the TMT and Torque Test (1) to determine laterality. Concerning the performance of dominant hand, the following effects were significant (ANCOVA): diagnosis (p=O.Ol), strategy (p=O.Ol) and age (p=O.O3). Siblings and healthy subjects reached the highest scores, schizophrenics the worst ones. The use of verbal strategy led to better results. No significant effects of diagnosis, strategy and
188
age on the performance of nondominant hand were found. The threedimensional observed frequency table (Table 1) was analyzed with the use of long-linear models studying relations between diagnosis, strategy and starting hand. Cases with mixed dominance were excluded from this analysis. The model involving the interactions of diagnosis and strategy, and diagnosis and starting hand proved to be bestfitting (chi-square - 7.25, p=O.20). In schizophrenics the verbal strategy was extremely rare. In healthy subjects and in relatives, it was as frequent as the nonverbal one. Schizophrenics started to answer mostly with a dominant hand, while in controls the starting hand was influenced by the strategy of solution. These results are consistent with the hypothesis of left-hemisphere dysfunction and overactivation. The test results in schizophrenics decreased with the dose of neuroleptics and with the duration of illness (mainly results of dominant hand), and with the score in the factor Anergy of the BPRS (mostly performance of nondominant hand). 1.
Blau, T. JSAS 7:16, 1977.
Cataloa
of
Selected
Documents
Carr, S.A. British Journal of Psychiatry 3.
Eaton, E-M. et al. Psychiatry
4.
Gur, R.E. Journal Abnormal
Psycholoqv
5.
Posmurova, Psychiatry,
IVth
6.
Taylor, M.A. et al. American 1979
7.
Walker, H-A., Birch, G.H. Journal 151:341-351, 1979
Table 1. Observed Strategy start verbal
nonverb
M., Alda, 1986
M.
frequency table diagnosis neurotic healthy
Research
1:325-332,
Conaress
Psychiatry
Nervous
schizo
Psychology,
136~53-58,
87:226-238,
World
Journal
in
1980.
1979. 1978 of
Bioloaical
136:1031-1034,
and Mental
warents
sibs
Diseases
total
domin nondom
13 9
8 5
2 2
7 4
5 2
35 22
total
22
13
4
11
7
57
domin nondom
8 12
9 12
19 6
6 7
6 0
48 37
total
20
21
25
13
6
85
AND SCHIZOPHRENIA
Roger Thomas Department of Psychological Medicine, University Medicine, Heath Park, Cardiff CF4 4XN, UK
of Wales College
of
Laterality effects to small bright stimuli in the left, central and right visual fields were investigated in both normal and schizophrenic subjects. This was done to test the hypothesis of defective interhemispheric transfer in schizophrenia. Normals showed earlier latency and larger amplitude evoked potentials over the directly stimulated hemisphere, and a smaller delayed response over the indirectly stimulated one, compatible with a possible transmission across the corpus callosum. This asymmetry of latency was lost in schizophrenic subjects even if they were free of medication. Possible interpretations may be related to recent work on agenesis of the corpus callosum and its association with schizophrenia.
IX c.
Neuropsychological
TACTILE TIVES
MEMORY
TEST
IN SCHIZOPHRENICS
M. Alda, M. Posmurova, Psychiatric
and other Related Tests
AND
THEIR
FIRST-DEGREE
RELA-
and P. Zvolsky
Research Unit, Charles University,
Prague, Czechoslovakia
On the basis of neuropsychological findings, various hypotheses on cerebral dysfunction in schizophrenia have been suggested: a dominant hemisphere dysfunction (61, both left hemisphere dysfunction and overactivation (41, a disruption in the system which balances the activity of the left and right hemispheres (31, and a fault in the interhemispheric transfer of information (2,7). One of the methods by means of which these disorders can be studied is the Tactile Memory Test (TMT) (Mika, unpublished) in which fingers on both hands touched simultaneously are to be remembered. This test allows not only the of the right and left hands, but also a study of a performance preference of the strategy of solution (51, (i.e., verbal - supposedly connected with dominant-hemisphere functions, and nonverbal, tactile - dependent on nondominant-hemisphere functions). Subjects for this study were 56 patients with an RDC diagnosis of schizophrenia, their 36 healthy parents and 19 healthy siblings, 54 nonpsychotic patients, mostly with psychosomatic complaints, and 57 healthy subjects. All the subjects were examined by the TMT and Torque Test (1) to determine laterality. Concerning the performance of dominant hand, the following effects were significant (ANCOVA): diagnosis (p=O.Ol), strategy (p=O.Ol) and age (p=O.O3). Siblings and healthy subjects reached the highest scores, schizophrenics the worst ones. The use of verbal strategy led to better results. No significant effects of diagnosis, strategy and
188
age on the performance of nondominant hand were found. The threedimensional observed frequency table (Table 1) was analyzed with the use of long-linear models studying relations between diagnosis, strategy and starting hand. Cases with mixed dominance were excluded from this analysis. The model involving the interactions of diagnosis and strategy, and diagnosis and starting hand proved to be bestfitting (chi-square - 7.25, p=O.20). In schizophrenics the verbal strategy was extremely rare. In healthy subjects and in relatives, it was as frequent as the nonverbal one. Schizophrenics started to answer mostly with a dominant hand, while in controls the starting hand was influenced by the strategy of solution. These results are consistent with the hypothesis of left-hemisphere dysfunction and overactivation. The test results in schizophrenics decreased with the dose of neuroleptics and with the duration of illness (mainly results of dominant hand), and with the score in the factor Anergy of the BPRS (mostly performance of nondominant hand). 1.
Blau, T. JSAS 7:16, 1977.
Cataloa
of
Selected
Documents
Carr, S.A. British Journal of Psychiatry 3.
Eaton, E-M. et al. Psychiatry
4.
Gur, R.E. Journal Abnormal
Psycholoqv
5.
Posmurova, Psychiatry,
IVth
6.
Taylor, M.A. et al. American 1979
7.
Walker, H-A., Birch, G.H. Journal 151:341-351, 1979
Table 1. Observed Strategy start verbal
nonverb
M., Alda, 1986
M.
frequency table diagnosis neurotic healthy
Research
1:325-332,
Conaress
Psychiatry
Nervous
schizo
Psychology,
136~53-58,
87:226-238,
World
Journal
in
1980.
1979. 1978 of
Bioloaical
136:1031-1034,
and Mental
warents
sibs
Diseases
total
domin nondom
13 9
8 5
2 2
7 4
5 2
35 22
total
22
13
4
11
7
57
domin nondom
8 12
9 12
19 6
6 7
6 0
48 37
total
20
21
25
13
6
85