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Symptom correlates of eye tracking dysfunction
Brief Reports
BIOL PSYCHIATRY 1987:22:919-921
919
Symptom Correlates of Eye Tracking Dysfunction Robert J. van den Bosch, Nice Rozendaal, and Jan M.F.A. Mol
The presence of impaired eye tracking in psychotic patients is well established, but the specificity of this dysfunction to psychotic disturbances is less clear. Similar impairments occur in many patients with an affective disorder (Lipton et al. 1983), but they may have mood-congruent psychotic features. We examined the specificity question by studying the associations between eye tracking and psychoticism measures, as well as psychotic symptom ratings, in a mixed sample of psychiatric outpatients and recently admitted in~tients. Simple reaction time was measured because of its status as a psychophysiological correlate of schizophrenia and related disorders (Nuechterlein 1977), and a frontal function test was included, as eye tracking impairment has been attributed to frontal dysfunction (Levin 1984).
Methods One hundred and five patients were studied: 48 men and 57 women. Mean age was 35.9 years (SD 9.7), and mean total lifetime hospi~ization was 5.2 months (SD 11.6). Diagnostic measures obtained during an extensive interview included diagnosis according to DSM-III (APA 1980), psychotic symptom ratings according to the Pre-
FromtheDepartment of Psychiatry,
University of Groningen (R.J. van den B.); the Psychiatric Hospital Welterhof, He&en (N.R.); ami the Department of Clinical Neurophysiology, University of Limburg (J.M.F.A.M.), The Netherlands. Address reprint requests to Dr. R. 1. van den Bosch, Psych&r&he U~v~i~i~~, Academisch Zieke&tis, Postbus 30.001,9?@1 RB Groningen, T&e Netherhutds. Received June 28, 1986; revised November 19, 1986.
0 1987 Society of Biological Psychiatry
sent State Ex~nation (PSE) (Wing et al. 1974), and ratings on the Scales of Psychotic and Psychotic-like Experiences (Chapman and Chapman 1980). Other measures included self-ratings on the Petcepmal Aberration scale (Chapman et al. 1978), the Magical Ideation scale (Eckblad and Chapman 1983), the Physical Anhedonia scale (Chapman et al. 1976), the P-scale from the Eysenck Personality Questionnaire (EPQ) (Eysenck and Eysenck 1975), the Unfriendly World scale from the Differential Personality Questionnaire (Tellegen 1978), the Schizop~nism scale {Nielsen and Petersen 1976), the Schizoidia scale (Golden and Meehl 1979), and the Neuroticism scale from the EPQ. Exclusion criteria were ocular defects, organic brain dysfunction, lithium medication, age below 20 or above 60 years, and substance abuse. Eye movements were recorded electrooculographically. Subjects tracked a luminous spot horizontally traversing 20” of visual arc across an oscilloscope screen at a frequency of 0.4 Hz during 80 sec. The analyses were based on the mean root-mean square error deviation (RMS) score of the four best periods among the total sequence (Lykken et al. 1981). Reaction time was measured during an irregular series of 16 trials with auditory warning and imperative stimuli and preparatory intervals of 3 sec. Frontal function was measured by the Sequential Matching Memory Task (SMMT) (Lezak 1983). The total sample was tripartitioned according to eye tracking score, in order to compare groups with good (RMS score CO. 1070) and with poor (RMS score >O. 1570) tracking quality (35 patients each). Correlative analyses were performed as well. 0006-3223/87/$03.50
920
BIOL PSYCHIATRY 1981:?2:919-921
Brief Reports
Results The good and poor tracking groups were not significantly different in sex composition and lifetime hospitalization, but the poor trackers were significantly older (38.7 versus 33.7 years, p < 0.05). The good tracking group contained 14 psychotic patients (4 schizophrenics) and 21 nonpsychotics (6 affective disorder patients). The poor tracking group contained 17 psychotics (8 schizophrenics) and 18 nonpsychotics (12 affective disorder patients) (DSM-III criteria). Both groups were significantly different in PSE symptom score (p < 0.02), Perceptual Aberration (p < O.OOl), and Magical Ideation (p < 0.05), with the poor trackers scoring higher. Omitting patients using antipsychotic medication (a total of six) did not influence the results. Additional analyses were performed in subsamples, excluding affective disorder and older (>50 years) patients, as eye tracking impairment in these persons seems to represent different phenomena than those observed in psychotic patients (Iacone and Koenig 1983; Lipton et al. 1983). This led to somewhat more pronounced differences, with psychotic experiences and physical anhedonia also being significantly different (Table 1). The correlations between eye tracking and diagnostic ratings in the total sample were low, ranging between 0.03 and 0.33 (perceptual ab-
erration), but became somewhat higher when affective disorder and older patients were excluded: significant correlations were found with the PSE score (0.26, p < O.Ol), psychotic experiences (0.24, p < 0.05), perceptual aberration (0.39,~ < O.Ol), and magical ideation (0.29, p < 0.01). SMMT score (0.19, p < 0.05) and reaction time (0.26, p < 0.01) correlated low. but also significantly, with eye tracking. There were no significant associations with PSE syndromes, notably the nuclear syndrome. We examined the specificity of associations between eye tracking and frontal dysfunction (Levin 1984), as well as reaction time latency (Van den Bosch 1984), by subdividing the good and poor tracking groups into psychotic and nonpsychotic groups (DSM-III criteria). Reaction time appeared to be not significantly different between psychotics and nonpsychotics within eye tracking samples. SMMT performance was significantly poorer in psychotic patients compared to nonpsychotic patients, but only in the poor tracking sample (t = 2.82, p < 0.01).
Discussion Eye tracking dysfunction is associated with a variety of psychotic and psychotiform experiences in psychiatric patients, especially when affective disorder and older patients are ex-
I. Means and Standard Deviations of Diagnostic Ratings and Other Measures in Patient Groups with Good and Poor Eye Tracking, Affective Disorder and Older Patients Being Excluded
Table
Sex (male/female) Age (years) Total lifetime hospitalization (months) PSE-number of psychotic symptoms Psychotic experiences-mean score Perceptual aberration Magical ideation Physical anhedonia P WQ) Unfriendly world Schizophrenism Schizoidia Neuroticism (EPQ) Reaction time (msec) SMMT (errors)
RMS CO. 1070 (II = 28)
RMS >O. 1570 (n = 21)
13115 32.4 (7.1) 4.6 (15.9) I .9 (2.6) 2.4 (1.9) 3.9 (4.7) 6.7 (3.4) 15.8 (5.9) 4.1 (2.8) 6.1 (5.6) x.3 (5.3) 3.6 (1.8) 14.8 (5.0) 267 (91) 3.4 (5.1)
10/l 1 35.7 (9.3) 3.7 (4.1) 4.7 (5.0) 3.7 (2.4) 10.6 (9.0) II.1 (7.1) 12.6 (4.3) 5.4 (2.9) 8.5 (4.9) 8.9 (2.7) 3.8 (1.2) 16.3 (5.0) 361 (151) 5.9 (5.6)
r
1.41 0.25 2.49 2.02 3.41 2.54 2.10 I .53 1.55 0.46 0.42 1.06 2.50 I .59
(NS) (NS) @ < @ < @ < @ < @ < (NS) (NS) (NS) (NS) (NS) @ < (NS)
0.01) 0.05) 0.001) 0.01) 0.05)
0.01)
BIOL PSYCHIATRY 1987;22:919-921
Brief Reports
eluded. Associations between poor eye tracking and high psychoticism ratings have been reported previously, but those studies were less extensive (Iacono and Lykken 1979; Siever et al. 1982; Van den Bosch 1984). The DSM-III, PSE (nuclear syndrome), and physical anhedonia findings in the present study do not point to a specific association with the schizophrenia construct. Frontal dysfunction seems to play some role in psychotic patients with poor eye tracking, but not in their nonpsychotic counterparts. More detailed analyses, including a battery of frontal function tests, are needed to solve this issue. References American Psychiatric Association (1980): Diagnostic and Statistical Manual of Mental Disorders (ed 3). Washington: APA.
Chapman LJ, Chapman JP (1980): Scales for rating psychotic and psychotic-like experiences as continua. Schizophr Bull 6:476. Chapman LJ, Chapman JP, Raulin ML (1976): Scales for physical and social anhedonia. J Abnorm Psychol85:374.
Chapman LJ, Chapman JP, Raulin ML (1978): Bodyimage aberration in schizophrenia. J Abnorm Psychol 87:399.
Eckblad M, Chapman LJ (1983): Magical ideation as an indicator of schizotypy. J Consult Clin Psychol51:215.
Eysenck HJ, Eysenck SBG (1975): Manual of the Eysenck Personality Questionnaire. London: Hodder and Stoughton. Golden RR, Meehl PE (1979): Detection of the schizoid taxon with MMPI indicators. J Abnorm Psychol 88:217.
921
Iacono WG, Lykken DT (1979): Eye tracking and psychopathology. New procedures applied to a sample of normal monozygotic twins. Arch Gen Psychiatry 36: 1361.
Iacono WG, Koenig WGR (1983): Features that distinguish the smooth-pursuit eye-tracking performance of schizophrenic, affective-disorder, and normal individuals. J Abnorm Psycho1 92:29. Levin S (1984): Frontal lobe dysfunctions in schizophrenia-1. Eye movement impairments. J Psychiatr Res 18:27.
Lezak MD (1983): Neuropsychological Assessment (ed 2). New York: Oxford University Press. Lipton RB, Levy DL, Holzman PS, Levin S (1983): Eye movement dysfunctions in psychiatric patients: A review. Schizophr Bull 9: 13. Lykken DT, Iacono WG, Lykken JD (1981): Measuring deviant eye tracking. Schizophr Bull 7:204. Nielsen TC, Petersen KE (1976): Electrodermal correlates of extraversion, trait anxiety and schizophrenism. Scan J Psycho1 17:73. Nuechterlein KH (1977): Reaction time and attention in schizophrenia: A critical evaluation of the data and theories. Schizophr Bull 3~373. Siever LJ, Haier RJ, Coursey RD, Sostek AJ, Murphy DL, Holzman PS, Buchsbaum MS (1982): Smooth pursuit eye tracking impairment. Relation to other ‘markers’ of schizophrenia and psychologic correlates. Arch Gen Psychiatry 39: 1001. Tellegen A (1978): Manual of the Differential Personality Questionnaire. Minneapolis: University of Minnesota. Van den Bosch RJ (1984): Eye tracking impairment: Attentional and psychometric correlates in psychiatric patients. J Psychiatr Res 18:277. Wing JK, Cooper JE, Sartorius N (1974): Measurement and Classa#icationof Psychiatric Symptoms.
Cambridge: Cambridge University Press.
BIOL PSYCHIATRY 1987:22:919-921
919
Symptom Correlates of Eye Tracking Dysfunction Robert J. van den Bosch, Nice Rozendaal, and Jan M.F.A. Mol
The presence of impaired eye tracking in psychotic patients is well established, but the specificity of this dysfunction to psychotic disturbances is less clear. Similar impairments occur in many patients with an affective disorder (Lipton et al. 1983), but they may have mood-congruent psychotic features. We examined the specificity question by studying the associations between eye tracking and psychoticism measures, as well as psychotic symptom ratings, in a mixed sample of psychiatric outpatients and recently admitted in~tients. Simple reaction time was measured because of its status as a psychophysiological correlate of schizophrenia and related disorders (Nuechterlein 1977), and a frontal function test was included, as eye tracking impairment has been attributed to frontal dysfunction (Levin 1984).
Methods One hundred and five patients were studied: 48 men and 57 women. Mean age was 35.9 years (SD 9.7), and mean total lifetime hospi~ization was 5.2 months (SD 11.6). Diagnostic measures obtained during an extensive interview included diagnosis according to DSM-III (APA 1980), psychotic symptom ratings according to the Pre-
FromtheDepartment of Psychiatry,
University of Groningen (R.J. van den B.); the Psychiatric Hospital Welterhof, He&en (N.R.); ami the Department of Clinical Neurophysiology, University of Limburg (J.M.F.A.M.), The Netherlands. Address reprint requests to Dr. R. 1. van den Bosch, Psych&r&he U~v~i~i~~, Academisch Zieke&tis, Postbus 30.001,9?@1 RB Groningen, T&e Netherhutds. Received June 28, 1986; revised November 19, 1986.
0 1987 Society of Biological Psychiatry
sent State Ex~nation (PSE) (Wing et al. 1974), and ratings on the Scales of Psychotic and Psychotic-like Experiences (Chapman and Chapman 1980). Other measures included self-ratings on the Petcepmal Aberration scale (Chapman et al. 1978), the Magical Ideation scale (Eckblad and Chapman 1983), the Physical Anhedonia scale (Chapman et al. 1976), the P-scale from the Eysenck Personality Questionnaire (EPQ) (Eysenck and Eysenck 1975), the Unfriendly World scale from the Differential Personality Questionnaire (Tellegen 1978), the Schizop~nism scale {Nielsen and Petersen 1976), the Schizoidia scale (Golden and Meehl 1979), and the Neuroticism scale from the EPQ. Exclusion criteria were ocular defects, organic brain dysfunction, lithium medication, age below 20 or above 60 years, and substance abuse. Eye movements were recorded electrooculographically. Subjects tracked a luminous spot horizontally traversing 20” of visual arc across an oscilloscope screen at a frequency of 0.4 Hz during 80 sec. The analyses were based on the mean root-mean square error deviation (RMS) score of the four best periods among the total sequence (Lykken et al. 1981). Reaction time was measured during an irregular series of 16 trials with auditory warning and imperative stimuli and preparatory intervals of 3 sec. Frontal function was measured by the Sequential Matching Memory Task (SMMT) (Lezak 1983). The total sample was tripartitioned according to eye tracking score, in order to compare groups with good (RMS score CO. 1070) and with poor (RMS score >O. 1570) tracking quality (35 patients each). Correlative analyses were performed as well. 0006-3223/87/$03.50
920
BIOL PSYCHIATRY 1981:?2:919-921
Brief Reports
Results The good and poor tracking groups were not significantly different in sex composition and lifetime hospitalization, but the poor trackers were significantly older (38.7 versus 33.7 years, p < 0.05). The good tracking group contained 14 psychotic patients (4 schizophrenics) and 21 nonpsychotics (6 affective disorder patients). The poor tracking group contained 17 psychotics (8 schizophrenics) and 18 nonpsychotics (12 affective disorder patients) (DSM-III criteria). Both groups were significantly different in PSE symptom score (p < 0.02), Perceptual Aberration (p < O.OOl), and Magical Ideation (p < 0.05), with the poor trackers scoring higher. Omitting patients using antipsychotic medication (a total of six) did not influence the results. Additional analyses were performed in subsamples, excluding affective disorder and older (>50 years) patients, as eye tracking impairment in these persons seems to represent different phenomena than those observed in psychotic patients (Iacone and Koenig 1983; Lipton et al. 1983). This led to somewhat more pronounced differences, with psychotic experiences and physical anhedonia also being significantly different (Table 1). The correlations between eye tracking and diagnostic ratings in the total sample were low, ranging between 0.03 and 0.33 (perceptual ab-
erration), but became somewhat higher when affective disorder and older patients were excluded: significant correlations were found with the PSE score (0.26, p < O.Ol), psychotic experiences (0.24, p < 0.05), perceptual aberration (0.39,~ < O.Ol), and magical ideation (0.29, p < 0.01). SMMT score (0.19, p < 0.05) and reaction time (0.26, p < 0.01) correlated low. but also significantly, with eye tracking. There were no significant associations with PSE syndromes, notably the nuclear syndrome. We examined the specificity of associations between eye tracking and frontal dysfunction (Levin 1984), as well as reaction time latency (Van den Bosch 1984), by subdividing the good and poor tracking groups into psychotic and nonpsychotic groups (DSM-III criteria). Reaction time appeared to be not significantly different between psychotics and nonpsychotics within eye tracking samples. SMMT performance was significantly poorer in psychotic patients compared to nonpsychotic patients, but only in the poor tracking sample (t = 2.82, p < 0.01).
Discussion Eye tracking dysfunction is associated with a variety of psychotic and psychotiform experiences in psychiatric patients, especially when affective disorder and older patients are ex-
I. Means and Standard Deviations of Diagnostic Ratings and Other Measures in Patient Groups with Good and Poor Eye Tracking, Affective Disorder and Older Patients Being Excluded
Table
Sex (male/female) Age (years) Total lifetime hospitalization (months) PSE-number of psychotic symptoms Psychotic experiences-mean score Perceptual aberration Magical ideation Physical anhedonia P WQ) Unfriendly world Schizophrenism Schizoidia Neuroticism (EPQ) Reaction time (msec) SMMT (errors)
RMS CO. 1070 (II = 28)
RMS >O. 1570 (n = 21)
13115 32.4 (7.1) 4.6 (15.9) I .9 (2.6) 2.4 (1.9) 3.9 (4.7) 6.7 (3.4) 15.8 (5.9) 4.1 (2.8) 6.1 (5.6) x.3 (5.3) 3.6 (1.8) 14.8 (5.0) 267 (91) 3.4 (5.1)
10/l 1 35.7 (9.3) 3.7 (4.1) 4.7 (5.0) 3.7 (2.4) 10.6 (9.0) II.1 (7.1) 12.6 (4.3) 5.4 (2.9) 8.5 (4.9) 8.9 (2.7) 3.8 (1.2) 16.3 (5.0) 361 (151) 5.9 (5.6)
r
1.41 0.25 2.49 2.02 3.41 2.54 2.10 I .53 1.55 0.46 0.42 1.06 2.50 I .59
(NS) (NS) @ < @ < @ < @ < @ < (NS) (NS) (NS) (NS) (NS) @ < (NS)
0.01) 0.05) 0.001) 0.01) 0.05)
0.01)
BIOL PSYCHIATRY 1987;22:919-921
Brief Reports
eluded. Associations between poor eye tracking and high psychoticism ratings have been reported previously, but those studies were less extensive (Iacono and Lykken 1979; Siever et al. 1982; Van den Bosch 1984). The DSM-III, PSE (nuclear syndrome), and physical anhedonia findings in the present study do not point to a specific association with the schizophrenia construct. Frontal dysfunction seems to play some role in psychotic patients with poor eye tracking, but not in their nonpsychotic counterparts. More detailed analyses, including a battery of frontal function tests, are needed to solve this issue. References American Psychiatric Association (1980): Diagnostic and Statistical Manual of Mental Disorders (ed 3). Washington: APA.
Chapman LJ, Chapman JP (1980): Scales for rating psychotic and psychotic-like experiences as continua. Schizophr Bull 6:476. Chapman LJ, Chapman JP, Raulin ML (1976): Scales for physical and social anhedonia. J Abnorm Psychol85:374.
Chapman LJ, Chapman JP, Raulin ML (1978): Bodyimage aberration in schizophrenia. J Abnorm Psychol 87:399.
Eckblad M, Chapman LJ (1983): Magical ideation as an indicator of schizotypy. J Consult Clin Psychol51:215.
Eysenck HJ, Eysenck SBG (1975): Manual of the Eysenck Personality Questionnaire. London: Hodder and Stoughton. Golden RR, Meehl PE (1979): Detection of the schizoid taxon with MMPI indicators. J Abnorm Psychol 88:217.
921
Iacono WG, Lykken DT (1979): Eye tracking and psychopathology. New procedures applied to a sample of normal monozygotic twins. Arch Gen Psychiatry 36: 1361.
Iacono WG, Koenig WGR (1983): Features that distinguish the smooth-pursuit eye-tracking performance of schizophrenic, affective-disorder, and normal individuals. J Abnorm Psycho1 92:29. Levin S (1984): Frontal lobe dysfunctions in schizophrenia-1. Eye movement impairments. J Psychiatr Res 18:27.
Lezak MD (1983): Neuropsychological Assessment (ed 2). New York: Oxford University Press. Lipton RB, Levy DL, Holzman PS, Levin S (1983): Eye movement dysfunctions in psychiatric patients: A review. Schizophr Bull 9: 13. Lykken DT, Iacono WG, Lykken JD (1981): Measuring deviant eye tracking. Schizophr Bull 7:204. Nielsen TC, Petersen KE (1976): Electrodermal correlates of extraversion, trait anxiety and schizophrenism. Scan J Psycho1 17:73. Nuechterlein KH (1977): Reaction time and attention in schizophrenia: A critical evaluation of the data and theories. Schizophr Bull 3~373. Siever LJ, Haier RJ, Coursey RD, Sostek AJ, Murphy DL, Holzman PS, Buchsbaum MS (1982): Smooth pursuit eye tracking impairment. Relation to other ‘markers’ of schizophrenia and psychologic correlates. Arch Gen Psychiatry 39: 1001. Tellegen A (1978): Manual of the Differential Personality Questionnaire. Minneapolis: University of Minnesota. Van den Bosch RJ (1984): Eye tracking impairment: Attentional and psychometric correlates in psychiatric patients. J Psychiatr Res 18:277. Wing JK, Cooper JE, Sartorius N (1974): Measurement and Classa#icationof Psychiatric Symptoms.
Cambridge: Cambridge University Press.