Eye tracking in patients with unipolar and bipolar affective disorders in remission.

Examined patients (20–66 yrs old) with a history of recurrent affective disorder on a variety of smooth-pursuit and saccadic eye-tracking tasks and on psychomotor analogs of these tasks. The 25 unipolar and 24 bipolar Ss were compared to 24 schizophrenics; all Ss were in remission. Results indicate that the performance of the 2 affective-disorder groups was not significantly different from that of the controls on any of these tasks. Smooth-pursuit tracking error was greater for Ss receiving Li and for those with a higher frequency of prior episodes of the disorder. When the pursuit eye movements of these Ss were compared to those of the schizophrenics, the latter produced more tracking error than both affective-disorder groups but significantly so only with respect to unipolar Ss. Although findings are consistent with the interpretation that tracking dysfunction is not a trait characteristic of affective disorders, further investigations contrasting remitted patients with bipolar and schizophrenic disorders are needed to determine the specificity of deviant tracking to schizophrenia. (38 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Value of beat-to-beat blood pressure changes, detected by pulse transit time, in the management of the obstructive sleep apnoea/hypopnoea syndrome

BACKGROUND: Previous studies of oculomotor dysfunction in schizophrenia have tended to concentrate on abnormalities of smooth pursuit eye tracking in chronic medicated patients. We report the results of a study of smooth pursuit, reflexive and antisaccade performance in drug naive and antipsychotic treated first-episode schizophrenic patients. METHODS: Smooth pursuit and saccadic eye movements were recorded in 36 first-episode schizophrenic patients and 36 controls matched for age and estimated IQ. The schizophrenic patients were divided into drug-naive (N = 17) and antipsychotic treated groups (N = 19). RESULTS: Smooth pursuit velocity gain was significantly lower than controls only in the drug-naive patients. The treated patients did not differ significantly from either the controls or the untreated group. In an antisaccade paradigm both treated and drug-naive schizophrenic patients demonstrated an increased number of errors, but only drug-naive patients also demonstrated an increased latency in initiating correct antisaccades. CONCLUSIONS: These impairments are unlikely to be due to a generalized deficit in oculomotor function in the schizophrenic groups, as there were no differences between the groups in saccadic metrics on a reflexive saccade task. The results show that both smooth pursuit and saccadic abnormalities are present at the onset of schizophrenia and are integral to the disorder.     

Anticipatory saccades during smooth pursuit eye movements and familial transmission of schizophrenia

BACKGROUND: Smooth pursuit eye movement (SPEM) abnormalities are a putative marker of genetic risk for schizophrenia. Accurate SPEM performance requires the subject to activate neural systems responsible for smooth pursuit tracking, while simultaneously suppressing activity of neurons responsible for saccadic movements that would move the eye ahead of the target. This study examined whether specific aspects of SPEM dysfunction cosegregate with genetic risk in parents of schizophrenic probands. METHODS: Eighteen probands and their parents had SPEM recorded. Parents with an ancestral history of schizophrenia were hypothesized to be more likely than their spouses without such a history to carry a genetic risk for schizophrenia. RESULTS: Ten families had a single parent with a positive ancestral history for schizophrenia. The frequency of anticipatory saccades, which were mostly small, and the fraction of total eye movement that they represented were the only measures that differentiated the more likely genetic carrier parents in these families from their spouses and age-matched normals. CONCLUSIONS: Failure to suppress saccadic anticipation of target motion during smooth pursuit appears an aspect of SPEM dysfunction related to presumed genetic risk for schizophrenia.     

Smooth pursuit eye movement and schizotypy in the community.

Deficits in smooth pursuit eye movements are well documented in schizophrenia and schizotypic psychopathology. The status of eye tracking dysfunction (ETD) as an endophenotype for schizophrenia liability is relatively robust. However, the relation of ETD to schizophrenia-related deviance in the general population has not been confirmed. This study examined smooth pursuit eye tracking and schizotypal personality features in the general population. Smooth pursuit eye movement and schizotypal features were measured in 300 adult community subjects. The sample included both sexes, subjects with a wide age and educational range, and subjects with no prior history of psychosis. Primary outcome measures were peak gain (eye velocity/target velocity), catch-up saccade rate, and schizotypal feature scores. Total schizotypal features were significantly associated with decreased peak gain and were associated at the trend level with increased catch-up saccade rate. These associations were essentially unchanged after controlling for age, sex, and intellectual level effects. These data confirm a hypothesized association between schizotypal features and poorer eye tracking performance (principally, peak gain) in the general population as well as support the conceptualization of ETD as an endophenotype for schizophrenia liability. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Saccadic eye movements in families multiply affected with schizophrenia: the Maudsley Family Study

OBJECTIVE: Family studies have shown that abnormalities of smooth pursuit eye movement are increased in the adult relatives of schizophrenic probands as well as in the probands themselves. More recently, an inability of schizophrenic subjects to inhibit reflexive saccades reliably has been shown. This study aimed to test the hypothesis that the latter dysfunction is part of the extended schizophrenia phenotype. METHOD: With the use of infrared oculography, measurements of reflexive saccades and antisaccades were undertaken in 29 probands with schizophrenia, 50 of their nonpsychotic first-degree relatives, and 38 unrelated healthy volunteers. RESULTS: Probands, relatives, and healthy subjects showed no overall differences in the generation of reflexive saccades. However, in the antisaccade task, probands showed more saccadic distractibility when they were required to inhibit reflexive saccades. Analysis of corrective saccades showed that this was not due to failed comprehension or motivation. Relatives of the probands with high saccadic distractibility showed a higher distractibility rate than relatives of the probands with normal distractibility. Across all subjects, females showed a higher rate of distractibility errors than males. CONCLUSIONS: The ability to suppress reflexive saccades is an objective neurocognitive measure that is impaired in schizophrenic patients and in a proportion of their biological relatives. This antisaccade abnormality may be a vulnerability marker in a subset of schizophrenic patients and their families.     

Eye movement impairment and schizotypal psychopathology

OBJECTIVE: Eye movement dysfunction in relation to a smooth pursuit task has been documented in schizophrenic patients and in patients with the related personality disorder, schizotypal personality disorder. To investigate which quantitative measures are associated with the eye movement dysfunction and whether the dysfunction is more related to the psychotic-like or the deficit-like symptoms of schizotypal personality disorder, ratings of eye movements in several groups of subjects were compared. METHOD: The study groups consisted of 26 patients with schizotypal personality disorder, 42 patients with other personality disorders (22 who also had two or more schizotypal personality traits and 20 who had fewer than two), and 37 normal comparison subjects. Smooth pursuit eye tracking of sinusoidal and constant velocity targets was recorded by an infrared eye tracking system. Two raters evaluated pursuit gain and large and small saccades in the direction of the target and in the direction opposite to that of the target (quantitative ratings) and constant velocity (qualitative rating). RESULTS: Patients with schizotypal personality disorder and patients with other personality disorders and two or more schizotypal traits, but not those with fewer than two schizotypal traits, had significantly poorer qualitative ratings of tracking than the normal comparison subjects. Neither gain nor any of the saccadic measures significantly differed between groups. The number of large saccades in the direction of the target was the only quantitative variable that predicted low qualitative ratings. Qualitatively poor tracking was associated with the deficit-like, but not the psychotic-like, symptoms of schizotypal personality disorder. CONCLUSIONS: Patients with schizotypal personality disorder demonstrate qualitatively poorer tracking than comparison groups, and the impaired tracking is associated with deficit-like symptoms.     

Neurophysiological markers of vulnerability to schizophrenia: Sensitivity and specificity of specific quantitative eye movement measures.

Eye-tracking deficits in schizophrenic patients and relatives have generated interest in using eye movements to mark schizophrenia liability. Efforts to develop specific quantitative measures have provided insight into the nature of the deficit and suggested what underlying neurophysiological mechanisms are involved. This study used receiver operating characteristic curve analyses to evaluate and compare the sensitivity, specificity, and overall accuracy of predicting disease liability using single and combined specific and global quantitative measures. Results indicate that measures of predictive pursuit and leading saccades significantly increased predictive accuracy compared with traditional global measures. Combining specific measures provided greater predictive accuracy compared with single measures. Implications for the use of specific eye movement measures to define schizophrenia-related phenotypes in genetic studies are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Microbial populations of Botrytis cinerea-inoculated strawberry fruit exposed to four volatile compounds

OBJECTIVE: The authors tested the hypothesis that eye tracking disorder in schizophrenia is associated with neurological signs. METHOD: The subjects were 93 normal comparison subjects and 59 schizophrenic patients. They were evaluated with the Neurological Evaluation Scale, a standardized rating instrument that assesses sensory integration, motor coordination, sequencing of complex motor acts, and other neurological signs. Also, the schizophrenic patients' smooth-pursuit eye movements were tested in response to a 0.3-Hz sinusoidal target by means of infrared oculography. They were divided into those with (N=18) and without (N=41) eye tracking disorder by using a previously described method, which was based on mixture analysis of the distribution of position root mean square error. RESULTS: The patients with eye tracking disorder had significantly worse performance than the patients without eye tracking disorder with respect to sensory integration, and the effect size was moderate to large. In comparison with the normal subjects, both patient subgroups had significantly worse performance on all of the Neurological Evaluation Scale subscales. CONCLUSIONS: Although neurological signs are present generally in schizophrenia, poor sensory integration is particularly pronounced in patients with eye tracking disorder. A review of the literature shows that the two abnormalities have strikingly similar patterns of validators, including 1) familial aggregation, 2) premorbid presence, 3) syndromal specificity, 4) trait status, and 5) association with the deficit syndrome. Poor sensory integration and eye tracking disorder in schizophrenia may be various manifestations of a common, underlying pathophysiological process.     

Smooth-pursuit eye tracking in first-episode psychotic patients and their relatives.

In order to determine the specificity of smooth-pursuit eye tracking dysfunction to schizophrenia (SC) and the prevalences of dysfunction among functionally psychotic and normal individuals, the authors investigated pursuit tracking in a large sample of psychotic patients, normal Ss, and 1st-degree relatives (N?=?482). Ss were recruited as part of an epidemiological study of 1st-episode psychosis that used a broadly based referral network to identify all cases in a major metropolitan area over a 2.5-yr period. Ss received diagnoses of SC, schizophreniform disorder, psychotic mood disorder, and paranoid or other psychotic disorder based on the Diagnostic and Statistical Manual of Mental Disorders (DSM-III). The distribution of tracking performance was bimodal for the SC Ss and their relatives, perhaps reflecting major gene action. Moreover, poor tracking ran in families. Pursuit tracking dysfunction was relatively specific to SC Ss and their relatives and occurred infrequently in other psychotic Ss and normal Ss. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Eye tracking disorder in schizophrenia is characterized by specific ocular motor defects and is associated with the deficit syndrome

The objective was to determine the relationships between eye tracking disorder (ETD) in schizophrenia, specific ocular motor measures, and the deficit syndrome. Twenty-five normal comparison subjects and 53 schizophrenic patients had eye movements tested with infrared oculography using a sinusoidal target. Patients were assessed with the Schedule for the Deficit Syndrome. For the patients, the distribution of position root mean square error (a global measure of pursuit) was best fit by a mixture of two normal distributions. This information was used to divide the patients into two subgroups, those with and those without ETD. ETD was almost completely accounted for by several specific ocular motor measures and was significantly associated with the deficit syndrome. The finding that ETD was almost completely accounted for by specific measures bridges a gap of interpretation in this field. ETD and the deficit syndrome of schizophrenia may share a common pathophysiology of cerebral cortical-subcortical circuits.     

Pursuit gain and saccadic intrusions in first-degree relatives of probands with schizophrenia.

Oculomotor functioning of 26 probands (aged 18–45 yrs) with schizophrenia, 12 spectrum and 46 nonspectrum 1st-degree relatives (aged 16–72 yrs), and 38 nonpsychiatric control Ss (aged 19–67 yrs) was evaluated. Spectrum relatives had more anticipatory saccades (ASs) and lower pursuit gain than nonspectrum relatives, who had more ASs and lower pursuit gain than control Ss. Probands also had lower pursuit gain than nonspectrum relatives and control Ss but did not differ from other groups on AS frequency. Control Ss had more globally accurate pursuit tracking (root mean square [RMS] error deviation) than both relative groups, whereas probands had the poorest RMS scores. Square wave jerk frequency did not differentiate the groups. Attention enhancement affected the frequency of ASs but did not affect either the other intrusive saccadic event or RMS scores. These results offer evidence that eye-movement dysfunction may serve as a biological marker for schizophrenia. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Infant attention and the development of smooth pursuit tracking.

The effect of attention on smooth pursuit and saccadic tracking was studied in infants at 8, 14, 20, and 26 weeks of age. A small rectangle was presented moving in a sinusoidal pattern in either the horizontal or vertical direction. Attention level was distinguished with a recording of heart rate. There was an increase across age in overall tracking, the gain of the smooth pursuit eye movements, and an increase in the amplitude of compensatory saccades at faster tracking speeds. One age change was an increase in the preservation of smooth pursuit tracking ability as stimulus speed increased. A second change was the increasing tendency during attentive tracking to shift from smooth pursuit to saccadic tracking when the stimulus speed increased to the highest velocities. This study shows that the development of smooth pursuit and targeted saccadic eye movements is closely related to the development of sustained attention in this age range. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Distinguishing schizophrenic patients from healthy controls by quantitative measurement of eye movement parameters

BACKGROUND: Eye tracking dysfunction is a putative trait marker for susceptibility to schizophrenia; however, it cannot be recommended as an additional tool for the diagnosis of schizophrenia, due to low sensitivity and specificity. METHODS: To assess the diagnostic potentials of combinations of eye movement paradigms, four smooth pursuit experiments (1: constant velocity of 15 degrees/sec; 2 and 3: combination with either visual or auditory distractors; 4: constant velocity of 30 degrees/sec) and two saccadic eye movement experiments (1: reflexive saccades; 2: voluntary saccades) were conducted. Fourteen patients with residual schizophrenia and 17 healthy controls were studied. Two sets of discriminant analyses (each with the resubstitution and with the "leaving one out" method) were calculated. RESULTS: In the first set, all 10 characteristic variables were included, whereas for the second set, the three most powerful parameters were selected (two from smooth pursuit tasks and one from a voluntary saccade experiment). This procedure provided the best classification results, regarding concordance between clinical diagnoses and eye movement dysfunction (kappa = .67-.80). CONCLUSIONS: Schizophrenic patients of the residual subtype can be differentiated from healthy individuals with considerable criterion validity on the basis of paradigms from two different ocular motor systems.     

A study of "atypical schizophrenia". Comparison with schizophrenia and affective disorder by sex, age of admission, precipitant, outcome, and family history

Eighty-five cases of atypical schizophrenia were compared with 200 of schizophrenia, 100 of bipolar (mania), and 225 of unipolar (depression) affective disorder. Comparisons were made on the basis of sex, age at admission, precipitating factors, outcome, and a family history of schizophrenia or of affective disorder. The atypical schizophrenia differed remarkably from the schizophrenia and most closely resembled the bipolar affective disorder when allowance was made for a younger age at onset and a higher frequency of precipitants. An analysis of symptoms verified the predominance of schizophrenic features in the atypical schizophrenia, but also showed a high percentage (80%) of patients who had one or more manic symptoms at index admission. It is concluded that great care should be taken in diagnosing schizophrenia in a patient who also has manic symptoms.     

Structural brain abnormalities in the major psychoses: A quantitative review of the evidence from computerized imaging.

The neuroimaging literature on structural brain abnormalities in the major psychoses is quantitatively reviewed. The mean effect size for studies of lateral ventriculomegaly in schizophrenia (d?=?.70) corresponded to 43% nonoverlap between the distributions of schizophrenics and control Ss. Planimetry yielded larger effects than linear methods of ventricular size estimation. Although enlargement of the third ventricle was comparable to that of lateral ventriculomegaly (d?=?.66), it was found to be significantly greater after differences in measurement method were taken into account. The average cumulative length of hospitalization, adjusted for patients' age and duration of illness, predicted ventriculomegaly in schizophrenia. Studies on schizophrenia and affective disorder differed neither in the extent of reported ventriculomegaly nor in the amount of "cortical atrophy." (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Global attentional deviance as a marker of risk for schizophrenia: Specificity and predictive validity.

Evaluated global attentional deficits as possible childhood markers of schizophrenia. Performance deviance was assessed across a continuous performance test, an attention span task, and the Digit Span subtest of the Wechsler Intelligence Scale for Children (WISC). 63 children of schizophrenic parents, 43 children of parents with affective disorders, and 100 children of normal parents were tested when the children were 7–12 yrs old. A subgroup of Ss at risk for schizophrenia displayed extreme global deviance across attentional measures. Only a small number of Ss at risk for affective disorders and normal comparison Ss showed similar extreme attentional deficits. The global attentional deficits measured at these early ages were related to behavioral disturbances (behavior was assessed in 3–6 mo intervals since 1971) in young adulthood for Ss at risk for schizophrenia, but not for Ss in the affective risk group or in the normal comparison group. It is concluded that global attentional deficits have considerable specificity for predicting behavioral problems thought to be precursors of schizophrenia or schizophrenia-related disorders. (54 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Comments on "Smooth-pursuit eye movements: A comparison of two measurement techniques" by Lindsey, Holzman, Haberman, and Yasillo.

D. T. Lindsey et al (1978) reported that the qualitative comparability of smooth-pursuit eye movement recordings derived from EOG and infrared reflection techniques is high. When Ss were examined who displayed what P. S. Holzman et al (1978) have labeled in their schizophrenic patients a "Type II" tracking dysfunction, there was poor correspondence between the 2 methods, indicating that the spikes evident in Type II tracking do not stem from movement of the eyes. (5 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Callosal transfer in schizophrenia: Too much or too little?

Evidence from diverse sources has pointed to an abnormality in callosal transfer in schizophrenia. To examine this further, a test was devised that measures Stroop interference and facilitation within and between the cerebral hemispheres. 46 heterogeneous schizophrenic patients were tested, and it was found that lateralized Stroop effects were equivalent in the left and right hemispheres and did not differ from normal or psychiatric (affective disorder) control Ss. In control Ss, Stroop effects that required interhemispheric transfer of coded information were reduced relative to those requiring intrahemispheric transfer, whereas among schizophrenic Ss, greater Stroop effects were found in the interhemispheric condition, presumably reflecting increased callosal connectivity. An index of callosal transfer did not correlate with gender, age, or IQ in any of the groups, nor did it relate to clinical characteristics in the schizophrenic Ss. The results support a specific functional abnormality of excessive callosal transfer in schizophrenia, though its role in pathogenesis remains unspecified. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Ocular motor abnormalities in Huntington's disease

We review here the eye movements in patients with Huntington's disease (HD), concentrating upon saccades as they show the most prominent abnormalities. Inability to suppress reflexive glances to suddenly appearing novel visual stimuli and delayed initiation of voluntary saccades, including predictive saccades, are early and consistent findings. These two abnormalities can be interpreted in the context of a model, based upon the idea that the frontal lobes and basal ganglia contribute more to the control of voluntary than to reflexive types of saccades. Most patients eventually also show slow saccades but they are most prominent when the disease is early-onset. Slowing of saccades may reflect involvement of both the higher-level cerebral centers that trigger saccades and the areas in the brain stem that produce premotor saccade commands. The study of eye movements in HD has led to a fruitful interaction between basic science and clinical investigation, and has served as a paradigm for examining higher-level defects in saccadic eye movement control in patients with various degenerative, neurological diseases or with focal cerebral hemispheral lesions.     

Features that distinguish the smooth-pursuit eye-tracking performance of schizophrenic, affective-disorder, and normal individuals.

Examined the eye-tracking records of 25 schizophrenic (mean age 37.6 yrs), 25 unipolar (mean age 37.9 yrs), 24 bipolar (mean age 36 yrs), and 46 medical control (mean age 35 yrs) patients. All the psychiatric patients were in symptom remission. All three psychiatric groups produced more oscillations than controls, and spiky tracking was correlated with poor performance as indexed by the production of large saccades. Schizophrenics did, however, produce smaller saccades and tracked with more phase lag than did each of the other groups. Results suggest that the smooth-pursuit system of schizophrenics is functionally different from that of normal people. Use of the phase lag as a potential marker of schizophrenia is discussed. (33 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)