Perceptual and Motor Skills, 1975,41, 219-224.
@ Perceptual and Motor Skills 1975
TEMPORAL INFORMATION PROCESSING A N D PSYCHOPATHOLOGY PETER CRAIN, SANFORD GOLDSTONE, A N D WILLIAM T. LHAMON Cornell University Medical College Summary.-Prior studies showed impaired temporal discrimination by schizophrenic and neurologic patients reflected in decreased information transmission. This report describes a study of 8 more carefully diagnosed schizophrenic patients, separating those with neurologic signs. Using temporal discrimination tasks involving two psychophysical methods, 8 schizophrenic patients with no organic signs did not differ from 17 nonpsychotic, nonorganic patients; an organic group ( n = 5 ) transmitted less information than the other patient samples. It is suggested that prior results were a product of casual diagnosis that ignored organic factors; reduced efficiency of temporal processing is associated predominantly with neurologic impairment.
This study represents a clarification and partial retraction of a report (Lhamon & Goldstone, 1973) that told of impaired temporal processing by schizophrenic patients. These patients were defined exclusively by chart diagnosis and yielded less transmitted information than healthy controls. This was confirmed by Locke (1974) with similar unselected patients; however, the same deficit surfaced in a mixed group of neurologic disorders. Is this similarity between schizophrenia and brain disease real or artifact? A step toward clarification requires confirmation of this similarity in patient groups established by careful diagnostic criteria replacing casual acceptance of chart diagnoses in large samples. This report describes the study of serial admissions to a hospital unit during a prescribed period with careful diagnostic assessment by three clinicians using a standard scale to establish the presence of schizophrenia, grouping separately those patients with evidence of brain syndrome, even when fulfilling simultaneously the criteria for schizophrenia. This provided a "pure" group of schizophrenic patients, mixed psychotic and nonpsychotic brain syndromes, and various nonpsychotic patient groups. The time judgment methods and transmitted information measure were similar to those of previous snidies permitting comparison of results. The conceptual and mathematical details of these methods and measures are available elsewhere (Attneave, 1959; Garner, 1962; Lhamon & Goldstone, 1973; L a k e ,
1974).
METHOD Subjects Ss were 36 consecutive admissions during three months to a unit of a private psychiatric hospital; four withdrew leaving 32. Ss were 14 men and 18 women
220
P. CRAIN, ET AL.
age 17 to 70 yr. (Mdn 30 yr.) with duration of hospitalization 2 to 14 wk. (Mdn 6 wk.). During the first week after admission each patient was examined and classified by three clinicians using the New Haven Schizophrenia Index, interview, medical examination, and psychological testing. All examiners were required to agree upon classification which divided patients into two categories, psychotic and nonpsychotic, and then subdivided further for final diagnosis. Psychotic, N = 15: ( 1 ) Schizophrenic, n = 8. Included were patients diagnosed by all examiners and confirmed by New Haven Index score (Astrachan, et al., 1972) without demonstrated or s~lspectedneurologic disease. These patients had active thought disorder, would have been called schizophrenic by any diagnostic school, and were without neurologic involvement. ( 2 ) O~ganic, n = 5. These psychotic patients had at least one neurologic sign acceptable to all examiners, and included senile dementia, multiple sclerosis, toxic psychoses, and cns syphillis. Three of the five were also regarded as schizophrenic by at least one examiner. ( 3 ) Mood Disorder, n = 2. Manic-depressive and depressive psychoses were included here. Nonpsychotic, N = 17: ( 1) Borderline States, n = 7. These patients displayed severe ego impairment with deficit in judgment, impulse control, object relations and general adaptation. They were unable to work or develop lasting social relationships, and none fulfilled New Haven Index criteria for schizophrenia. ( 2 ) Neurotic-Personality Disorders, n = 7. These patients demonstrated more effective ego functioning than the borderline group. They participated in enduring social relationships and vocational pursuits, and typically suffered anxiety and depression. ( 3 ) Organic, n = 1. Nonpsychotic behavior pathology with organic signs; a fire setter with explosive, impulsive behavior and abnormal E.E.G. was included here. ( 4 ) Indete~nzinate,n = 2. When all examiners accepted patients as nonpsychotic and nonorganic but could not agree i~nanimouslyupon classificacion they were placed here. N o healthy controls were employed since this study was directed at questions of differences between patient groups. Time ludgmelzt Tests Durations were sounds played on a commercial casserte recorder; all durations were within 5% of the nominal and repeat accuracy was better than 1%. The sounds were presented through headphones as 1 KHz tones at the comfortable level of 70 d b ( r e 2 )( 10.5N/m2). Procedures.-Patients were tested wich the same two methods employed earlier (Lhamon & Goldstone, 1973) to permit comparison of data. (1) Single-stimulus: Seven durations in steps of 0.15 sec. from 0.15 to 1.05 sec. (short series), or 0.75 to 1.65 sec. (long series) were arranged haphazardly and presented seven times, yielding 49 judgments. Patients received the long
TEMPORAL INFORMATION PROCESSING AND PSYCHOPATHOLOGY 221
series first, followed by the short and judged the stimuli as shorter or longer than their concept of a clock second using a 7-category response scale: I, much less than one second; 2, less; 3, slightly less; 4, equal; 5 , slightly more; 6, more;'7, much more. ( 2 ) Pair-comparison: Patients received two successive durations separated by 2.00-sec. interstimuIus and 10.00-sec. interpair intervals and judged the last of the pair as longer or shorter than the first; the initial duration of each pair was 1.00 sec. followed by the judged variable duration. Two series were employed successively. The first had three variable durations (0.85, 1.00, 1.15 sec.) compared with the 1.00-sec. standard using a 3-category scale: 1, slightly shorter; 2, equal; 3, slightly longer. Each of the three different pairs was presented three times and the nine pairs were distributed haphazardly. Next, patients judged another series containing five variable durations (0.70, 0.85, 1.00, 1.15, 1.30 sec.) compared with the 1.00-sec. standard using a 5-category scale: I , shorter; 2, slightly shorter; 3, equal; 4, slightly longer; 5, longer. Each of the five different pairs was resented five times and the 25 pairs were distributed haphazardly. The sequence of testing was long series followed by short series singlestimulus, followed by 3-stimulus, 3-response and finally 5-stimulus, 5-response pair-comparison. Transmitted information ( U ( , ,,,) ) .-The two single-stimulus tasks yielded 7 X 7 stimulus-response matrices with 49 entries and pair-comparison produced 3 X 3 and 5 X 5 matrices with nine and 25 entries ~ieldingfour U,,:,, measures for each patient. All time judgment data remained "blind" until diagnoses were complete.
RESULTS The seven borderline and seven neurotic-personality disorder patients transmitted the same amount of information for single-stimulus ( t = 1.34, df = 13, p > . l o ) and pair-comparison ( t = 0.36, df = 13, p > . l o ) ; these two nonpsychotic groups were combined. The two indeterminate nonpsychotic patients were not different from others and they too were added, yielding a group of 16 nonpsychotic patients without organic brain disease. One patient in this group was diagnosed finally as chronic brain syndrome after the termination of the experiment but was retained in this nonpsychotic, nonorganic group to maintain the design of the study. The one organic nonpsychotic patient was added to the five organic psychotic patients producing a group of six with cns pathology. The two mood disorders and eight schizophrenics were kept separate. Fig. 1 displays the m e a n U(,:,.) obtained by each group for the two methods and four tests; mood disorders were not included due to the limited sample. Statistical tests using each of the two single-stimulus and two pair-comparison measures were never different from a combined score for each method; the corn-
P. CRAIN, ET AL. Nonpsychotic, nonorganlc pallents (n-16) Schizophrenic patients In-8) Organic patients (n-6)
.Long serles
Short serles
SINGLE STIMULUS
,
3x3
5x5
PA1 R COMPARISON
FIG. 1. Mean information transmission for each single-stimulus, i.e., absolute-iudgmenr, and pair-comparison test for all groups
bined score analysis will be reported. Inspection shows greater U(,:,,for the nonpsychotic, nonorganic than the schizophrenic patients in three of the four comparisons, but statistical analysis shows no significant difference for singlestimulus ( t = 0.60, df = 15, p > . l o ) and pair-comparison ( t = 1.21, df = 15, p > . l o ) measures; thus, schizophrenic and nonpsychotic, nonorganic patients produced similar results. It is clear that both schizophrenic and nonpsychotic, nonorganic patients were more efficient than the organic group. The nonpsychotic, nonorganic group differed significantly from the organlc group for single-stimulus ( t = 3.46 df = 21, p < ,005) and pair-compar~son ( t = 2.93, df = 21, p < .005); the schizophrenic and organic groups also differed significantly on single-stimulus ( t = 1.94, df = 13, p < .05) and pair-comparison ( t = 2.30, df = 13, p < ,025). In this study, patients with the diagnosis schizophrenia showed more efficient information processing than in prior studies, and the equivalence of organics and schizophrenics found previously (Lhamon & Goldstone, 1773; Locke, 1974) disappeared; only the organic group produced significant impairment. It is interesting to note that the two psychotic mood disorders produced results similar co those of the organic group; the one patient incorrectly diagnosed nonorganic yielded the lowest scores of her group and resembled the organics.
DISCUSSION Although altered time perception is viewed as a frequent companion of schizophrenia (Lewis, 1932), it has been difficult to locate invariant impairments in laboratory studies. Schizophrenic patients have been variously reported to overestimate, underestimate, or "normally" estimate magnitude of duration (Lhamon, Goldstone, & Goldfarb, 1965; Goldstone, 1967), and now the finding of impaired transmitted information (Lhamon & Goldstone, 1973; Locke, 1974) is questioned. With careful diagnosis that excluded patients with organic signs, pathology of discrimination and processing efficiency was reduced or did not appear at all. These results highlight the importance of looking carefully for organic factors in schizophrenia research, especially where a dimension of the sensorium, such as time, is involved. W e assume that the prior unselected samples of schizophrenic patients contained ignored or unrevealed organic cases that increased apparent deficit in these groups. Since no healthy control subjects were employed, the possibility remains that both nonpsychotic and schizophrenic patiencs were equally impaired with the organics simply showing more deficit. However, comparable data (Hibbard, et al., 1975) on healthy young people, healthy people of advanced age, and patients with senile dementia showed that the younger and older healthy subjects were similar to nonpsychotics and schizophrenics reported here; those senile dementia and these organic patients yielded similar results. Although efforts to study the schizophrenic patients prior to medication was not possible, all prior studies employed subjects undergoing comparable pharmacotherapy and, hence, chis issue cannot account for the findings. Finally, diagnostic preference led the authors to initiate the study with borderline patients included as a nonpsychotic group. Since the results did not significantly differentiate schizophrenic from nonpsychotic groups, this study did not clarify the diagnostic picture for the category borderline. REFERENCES
ASTRACHAN, B. hi.,HARROW, M.,ADLER, D., BRAUER, L.,SCHWARTZ, A., SWARTZ, C., & TUCKER, G. A checklist for the diagnosis of schizophrenia. Brit. I . Psychiat., 1972, 121, 529-539.
ATTNEAVE, F. Applicationr o f information theory to psychology.
New York: Holt, Rineharc & Winston, 1959. GARNER, W . R. Uncertainty and structure as psychological concepts. New York: Wiley, 1962. GOLDSTONE, S. The human clock: a framework for the study of healthy and deviant time perception. I n R. Fischer ( E d . ) , Interdisciplinary perspectives of time. Annals N. Y. Acad. Sci., 1967, 138, 767-783. HIBBARD, T. R., MIGLIACCIO,J. N., GOLDSTONE, S., & LHAMON, W. T. Temporal information processing by young and senior adults, and patients with senile dementia. J . Geront., 1975, 30, 326-330. LEWIS, A. Experience of time in mental disorder. Proc. Roy. Soc. Med., 1932, 25, 611.
224
P. CRAIN, ET AL.
LHAMON,W. T., & GOI~DSTONE, S. Temporal information processing in schizophrenia. Arch. Gen. Psychiat., 1973, 28, 44-51. LHAMON,W. T., GOLDSTONE,S., & GOLDFARB,J. L. The psycho athology of time judgment. In P. H . Hoch gi J. Zubin (Eds.), T h e prychopatho8gy o f perception. New York: Grune & Stratton, 1965. Pp. 164-188. LOCKE, S. A. Temporal discrimination of brief auditory stimuli by schizophrenics, the neurologically impaired, and normals. Percepc. mot. S k i j l ~ ,1974, 39, 1111-1120.
Accepted May 28, 1975.
@ Perceptual and Motor Skills 1975
TEMPORAL INFORMATION PROCESSING A N D PSYCHOPATHOLOGY PETER CRAIN, SANFORD GOLDSTONE, A N D WILLIAM T. LHAMON Cornell University Medical College Summary.-Prior studies showed impaired temporal discrimination by schizophrenic and neurologic patients reflected in decreased information transmission. This report describes a study of 8 more carefully diagnosed schizophrenic patients, separating those with neurologic signs. Using temporal discrimination tasks involving two psychophysical methods, 8 schizophrenic patients with no organic signs did not differ from 17 nonpsychotic, nonorganic patients; an organic group ( n = 5 ) transmitted less information than the other patient samples. It is suggested that prior results were a product of casual diagnosis that ignored organic factors; reduced efficiency of temporal processing is associated predominantly with neurologic impairment.
This study represents a clarification and partial retraction of a report (Lhamon & Goldstone, 1973) that told of impaired temporal processing by schizophrenic patients. These patients were defined exclusively by chart diagnosis and yielded less transmitted information than healthy controls. This was confirmed by Locke (1974) with similar unselected patients; however, the same deficit surfaced in a mixed group of neurologic disorders. Is this similarity between schizophrenia and brain disease real or artifact? A step toward clarification requires confirmation of this similarity in patient groups established by careful diagnostic criteria replacing casual acceptance of chart diagnoses in large samples. This report describes the study of serial admissions to a hospital unit during a prescribed period with careful diagnostic assessment by three clinicians using a standard scale to establish the presence of schizophrenia, grouping separately those patients with evidence of brain syndrome, even when fulfilling simultaneously the criteria for schizophrenia. This provided a "pure" group of schizophrenic patients, mixed psychotic and nonpsychotic brain syndromes, and various nonpsychotic patient groups. The time judgment methods and transmitted information measure were similar to those of previous snidies permitting comparison of results. The conceptual and mathematical details of these methods and measures are available elsewhere (Attneave, 1959; Garner, 1962; Lhamon & Goldstone, 1973; L a k e ,
1974).
METHOD Subjects Ss were 36 consecutive admissions during three months to a unit of a private psychiatric hospital; four withdrew leaving 32. Ss were 14 men and 18 women
220
P. CRAIN, ET AL.
age 17 to 70 yr. (Mdn 30 yr.) with duration of hospitalization 2 to 14 wk. (Mdn 6 wk.). During the first week after admission each patient was examined and classified by three clinicians using the New Haven Schizophrenia Index, interview, medical examination, and psychological testing. All examiners were required to agree upon classification which divided patients into two categories, psychotic and nonpsychotic, and then subdivided further for final diagnosis. Psychotic, N = 15: ( 1 ) Schizophrenic, n = 8. Included were patients diagnosed by all examiners and confirmed by New Haven Index score (Astrachan, et al., 1972) without demonstrated or s~lspectedneurologic disease. These patients had active thought disorder, would have been called schizophrenic by any diagnostic school, and were without neurologic involvement. ( 2 ) O~ganic, n = 5. These psychotic patients had at least one neurologic sign acceptable to all examiners, and included senile dementia, multiple sclerosis, toxic psychoses, and cns syphillis. Three of the five were also regarded as schizophrenic by at least one examiner. ( 3 ) Mood Disorder, n = 2. Manic-depressive and depressive psychoses were included here. Nonpsychotic, N = 17: ( 1) Borderline States, n = 7. These patients displayed severe ego impairment with deficit in judgment, impulse control, object relations and general adaptation. They were unable to work or develop lasting social relationships, and none fulfilled New Haven Index criteria for schizophrenia. ( 2 ) Neurotic-Personality Disorders, n = 7. These patients demonstrated more effective ego functioning than the borderline group. They participated in enduring social relationships and vocational pursuits, and typically suffered anxiety and depression. ( 3 ) Organic, n = 1. Nonpsychotic behavior pathology with organic signs; a fire setter with explosive, impulsive behavior and abnormal E.E.G. was included here. ( 4 ) Indete~nzinate,n = 2. When all examiners accepted patients as nonpsychotic and nonorganic but could not agree i~nanimouslyupon classificacion they were placed here. N o healthy controls were employed since this study was directed at questions of differences between patient groups. Time ludgmelzt Tests Durations were sounds played on a commercial casserte recorder; all durations were within 5% of the nominal and repeat accuracy was better than 1%. The sounds were presented through headphones as 1 KHz tones at the comfortable level of 70 d b ( r e 2 )( 10.5N/m2). Procedures.-Patients were tested wich the same two methods employed earlier (Lhamon & Goldstone, 1973) to permit comparison of data. (1) Single-stimulus: Seven durations in steps of 0.15 sec. from 0.15 to 1.05 sec. (short series), or 0.75 to 1.65 sec. (long series) were arranged haphazardly and presented seven times, yielding 49 judgments. Patients received the long
TEMPORAL INFORMATION PROCESSING AND PSYCHOPATHOLOGY 221
series first, followed by the short and judged the stimuli as shorter or longer than their concept of a clock second using a 7-category response scale: I, much less than one second; 2, less; 3, slightly less; 4, equal; 5 , slightly more; 6, more;'7, much more. ( 2 ) Pair-comparison: Patients received two successive durations separated by 2.00-sec. interstimuIus and 10.00-sec. interpair intervals and judged the last of the pair as longer or shorter than the first; the initial duration of each pair was 1.00 sec. followed by the judged variable duration. Two series were employed successively. The first had three variable durations (0.85, 1.00, 1.15 sec.) compared with the 1.00-sec. standard using a 3-category scale: 1, slightly shorter; 2, equal; 3, slightly longer. Each of the three different pairs was presented three times and the nine pairs were distributed haphazardly. Next, patients judged another series containing five variable durations (0.70, 0.85, 1.00, 1.15, 1.30 sec.) compared with the 1.00-sec. standard using a 5-category scale: I , shorter; 2, slightly shorter; 3, equal; 4, slightly longer; 5, longer. Each of the five different pairs was resented five times and the 25 pairs were distributed haphazardly. The sequence of testing was long series followed by short series singlestimulus, followed by 3-stimulus, 3-response and finally 5-stimulus, 5-response pair-comparison. Transmitted information ( U ( , ,,,) ) .-The two single-stimulus tasks yielded 7 X 7 stimulus-response matrices with 49 entries and pair-comparison produced 3 X 3 and 5 X 5 matrices with nine and 25 entries ~ieldingfour U,,:,, measures for each patient. All time judgment data remained "blind" until diagnoses were complete.
RESULTS The seven borderline and seven neurotic-personality disorder patients transmitted the same amount of information for single-stimulus ( t = 1.34, df = 13, p > . l o ) and pair-comparison ( t = 0.36, df = 13, p > . l o ) ; these two nonpsychotic groups were combined. The two indeterminate nonpsychotic patients were not different from others and they too were added, yielding a group of 16 nonpsychotic patients without organic brain disease. One patient in this group was diagnosed finally as chronic brain syndrome after the termination of the experiment but was retained in this nonpsychotic, nonorganic group to maintain the design of the study. The one organic nonpsychotic patient was added to the five organic psychotic patients producing a group of six with cns pathology. The two mood disorders and eight schizophrenics were kept separate. Fig. 1 displays the m e a n U(,:,.) obtained by each group for the two methods and four tests; mood disorders were not included due to the limited sample. Statistical tests using each of the two single-stimulus and two pair-comparison measures were never different from a combined score for each method; the corn-
P. CRAIN, ET AL. Nonpsychotic, nonorganlc pallents (n-16) Schizophrenic patients In-8) Organic patients (n-6)
.Long serles
Short serles
SINGLE STIMULUS
,
3x3
5x5
PA1 R COMPARISON
FIG. 1. Mean information transmission for each single-stimulus, i.e., absolute-iudgmenr, and pair-comparison test for all groups
bined score analysis will be reported. Inspection shows greater U(,:,,for the nonpsychotic, nonorganic than the schizophrenic patients in three of the four comparisons, but statistical analysis shows no significant difference for singlestimulus ( t = 0.60, df = 15, p > . l o ) and pair-comparison ( t = 1.21, df = 15, p > . l o ) measures; thus, schizophrenic and nonpsychotic, nonorganic patients produced similar results. It is clear that both schizophrenic and nonpsychotic, nonorganic patients were more efficient than the organic group. The nonpsychotic, nonorganic group differed significantly from the organlc group for single-stimulus ( t = 3.46 df = 21, p < ,005) and pair-compar~son ( t = 2.93, df = 21, p < .005); the schizophrenic and organic groups also differed significantly on single-stimulus ( t = 1.94, df = 13, p < .05) and pair-comparison ( t = 2.30, df = 13, p < ,025). In this study, patients with the diagnosis schizophrenia showed more efficient information processing than in prior studies, and the equivalence of organics and schizophrenics found previously (Lhamon & Goldstone, 1773; Locke, 1974) disappeared; only the organic group produced significant impairment. It is interesting to note that the two psychotic mood disorders produced results similar co those of the organic group; the one patient incorrectly diagnosed nonorganic yielded the lowest scores of her group and resembled the organics.
DISCUSSION Although altered time perception is viewed as a frequent companion of schizophrenia (Lewis, 1932), it has been difficult to locate invariant impairments in laboratory studies. Schizophrenic patients have been variously reported to overestimate, underestimate, or "normally" estimate magnitude of duration (Lhamon, Goldstone, & Goldfarb, 1965; Goldstone, 1967), and now the finding of impaired transmitted information (Lhamon & Goldstone, 1973; Locke, 1974) is questioned. With careful diagnosis that excluded patients with organic signs, pathology of discrimination and processing efficiency was reduced or did not appear at all. These results highlight the importance of looking carefully for organic factors in schizophrenia research, especially where a dimension of the sensorium, such as time, is involved. W e assume that the prior unselected samples of schizophrenic patients contained ignored or unrevealed organic cases that increased apparent deficit in these groups. Since no healthy control subjects were employed, the possibility remains that both nonpsychotic and schizophrenic patiencs were equally impaired with the organics simply showing more deficit. However, comparable data (Hibbard, et al., 1975) on healthy young people, healthy people of advanced age, and patients with senile dementia showed that the younger and older healthy subjects were similar to nonpsychotics and schizophrenics reported here; those senile dementia and these organic patients yielded similar results. Although efforts to study the schizophrenic patients prior to medication was not possible, all prior studies employed subjects undergoing comparable pharmacotherapy and, hence, chis issue cannot account for the findings. Finally, diagnostic preference led the authors to initiate the study with borderline patients included as a nonpsychotic group. Since the results did not significantly differentiate schizophrenic from nonpsychotic groups, this study did not clarify the diagnostic picture for the category borderline. REFERENCES
ASTRACHAN, B. hi.,HARROW, M.,ADLER, D., BRAUER, L.,SCHWARTZ, A., SWARTZ, C., & TUCKER, G. A checklist for the diagnosis of schizophrenia. Brit. I . Psychiat., 1972, 121, 529-539.
ATTNEAVE, F. Applicationr o f information theory to psychology.
New York: Holt, Rineharc & Winston, 1959. GARNER, W . R. Uncertainty and structure as psychological concepts. New York: Wiley, 1962. GOLDSTONE, S. The human clock: a framework for the study of healthy and deviant time perception. I n R. Fischer ( E d . ) , Interdisciplinary perspectives of time. Annals N. Y. Acad. Sci., 1967, 138, 767-783. HIBBARD, T. R., MIGLIACCIO,J. N., GOLDSTONE, S., & LHAMON, W. T. Temporal information processing by young and senior adults, and patients with senile dementia. J . Geront., 1975, 30, 326-330. LEWIS, A. Experience of time in mental disorder. Proc. Roy. Soc. Med., 1932, 25, 611.
224
P. CRAIN, ET AL.
LHAMON,W. T., & GOI~DSTONE, S. Temporal information processing in schizophrenia. Arch. Gen. Psychiat., 1973, 28, 44-51. LHAMON,W. T., GOLDSTONE,S., & GOLDFARB,J. L. The psycho athology of time judgment. In P. H . Hoch gi J. Zubin (Eds.), T h e prychopatho8gy o f perception. New York: Grune & Stratton, 1965. Pp. 164-188. LOCKE, S. A. Temporal discrimination of brief auditory stimuli by schizophrenics, the neurologically impaired, and normals. Percepc. mot. S k i j l ~ ,1974, 39, 1111-1120.
Accepted May 28, 1975.
