Movements In Schizophrenia Research Articles

Assessment of Mental Imagery of Movement in Schizophrenia

Schizophrenia patients often present with neurological signs such as left/right confusion, impaired coordination of movements, and motor abnormalities may occur secondary to antipsychotic medications. Neuropsychological tests identify various dysfunctions, such as difficulty in focusing attention, difficulty in abstract thinking or difficulty in changing the response frame, while Neurophysiological tests show slowing down of reaction time, problems with eye tracking, etc. There are no studies in the international literature dealing with the investigation of mental imagery of movement in Greek patients with schizophrenia. Also, the position that patients with schizophrenia – regardless of their symptom profile, age, sex, and chronicity of the disease – have a permanent difficulty in creating and manipulating an internal model of their movement prediction has not been substantiated enough to date.

"Assessment of Mental Imagery of Movement in Schizophrenia"

"Assessment of Mental Imagery of Movement in Schizophrenia"

Assessment of Mental Imagery of Movement in Schizophrenia

Schizophrenia patients often present with neurological signs such as left/right confusion, impaired coordination of movements, and motor abnormalities may occur secondary to antipsychotic medications. Neuropsychological tests identify various dysfunctions, such as difficulty in focusing attention, difficulty in abstract thinking or difficulty in changing the response frame, while Neurophysiological tests show slowing down of reaction time, problems with eye tracking, etc. There are no studies in the international literature dealing with the investigation of mental imagery of movement in Greek patients with schizophrenia. Also, the position that patients with schizophrenia – regardless of their symptom profile, age, sex, and chronicity of the disease – have a permanent difficulty in creating and manipulating an internal model of their movement prediction, has not been substantiated enough to date. Aim: In the present study we examine the function of visual-motor coordination and the time to achieve the goal-directed movement of the dominant hand of patients with schizophrenia Method: The sample we used in our research consisted of patients with diagnosed schizophrenia and healthy individuals. Schizophrenia patients belonged to the experimental group and healthy subjects to the control group. The number of examined patients was 39 and the healthy 51. the assessment of the movement and its mental representation was carried out with the real and mental movement of the dominant hand between two square targets located at a distance of 20 cm, on white paper of A4 size. Conclusions: Visuomotor coordination of a specific hand movement differs between patients with schizophrenia and the normal population. In particular, the means of the goal-directed hand movement achievement time in the actual execution condition and in the mental execution condition of the patients were significantly higher than the corresponding times of the standard population.

Assessment of Mental Imagery of Movement in Schizophrenia

Assessment of Mental Imagery of Movement in Schizophrenia

Compromised Neural Circuit Dynamics Underlying Impaired Control of Eye Movements in Schizophrenia

Compromised Neural Circuit Dynamics Underlying Impaired Control of Eye Movements in Schizophrenia

In the eye of the beholder? Oxytocin effects on eye movements in schizophrenia

BackgroundIndividuals with schizophrenia have difficulty in extracting salient information from faces. Eye-tracking studies have reported that these individuals demonstrate reduced exploratory viewing behaviour (i.e. reduced number of fixations and shorter scan paths) compared to healthy controls. Oxytocin has previously been demonstrated to exert pro-social effects and modulate eye gaze during face exploration. In this study, we tested whether oxytocin has an effect on visual attention in patients with schizophrenia. MethodsNineteen male participants with schizophrenia received intranasal oxytocin 40UI or placebo in a double-blind, placebo-controlled, crossover fashion during two visits separated by seven days. They engaged in a free-viewing eye-tracking task, exploring images of Caucasian men displaying angry, happy, and neutral emotional expressions; and control images of animate and inanimate stimuli. Eye-tracking parameters included: total number of fixations, mean duration of fixations, dispersion, and saccade amplitudes. ResultsWe found a main effect of treatment, whereby oxytocin increased the total number of fixations, dispersion, and saccade amplitudes, while decreasing the duration of fixations compared to placebo. This effect, however, was non-specific to facial stimuli. When restricting the analysis to facial images only, we found the same effect. In addition, oxytocin modulated fixation rates in the eye and nasion regions. DiscussionThis is the first study to explore the effects of oxytocin on eye gaze in schizophrenia. Oxytocin had enhanced exploratory viewing behaviour in response to both facial and inanimate control stimuli. We suggest that the acute administration of intranasal oxytocin may have the potential to enhance visual attention in schizophrenia.

Asymmetries in initiation of aiming movements in schizophrenia

Several studies have reported motor symptoms in schizophrenia (SCZ), in some cases describing asymmetries in their manifestation. To date, biases were mainly reported for sequential movements, and the hypothesis was raised of a dopamine-related hemispheric imbalance. Aim of this research is to better characterize asymmetries in movement initiation in SCZ by exploring single actions. Fourteen SCZ patients and fourteen healthy subjects were recruited. On a trial-by-trial basis, participants were instructed to reach for one of eight possible targets. Measures of movement initiation and execution were collected. Starting point, target and moving limb were systematically varied to check for asymmetric responses. Results showed that SCZ patients, besides being overall slower than controls, additionally presented with a bias affecting both the moving hand and the side from which movements were initiated. This finding is discussed in relation to hemispheric lateralization in motor control.

Paryakula drishti of Unmada: Deficits of smooth pursuit eye movements and anti-saccades in schizophrenia

Bhuta vidya (Ayurvedic psychiatry) is one of the eight specialties of Ayurveda. Unmada is a broad term which includes various psychiatric disorders described in modern psychiatry. The classification, etiology, pathogenesis, signs and symptoms, prognosis, and treatment of Unmada are available in all Ayurvedic classical texts. Abnormal eye movements such as “Paryakula drishti” (abnormal eye movements which denotes excitement or confusion or agitation)/“Chakshusho aakulata” (abnormal eye movements denotes confusion or perplexity)/“Chakshusho aswasthatvam” (abnormal eye movements) and “Chakshushoscha apasarpanam” (abnormal tracking) are mentioned among various signs and symptoms of Unmada. In Ayurveda, till date, no studies have been conducted, and no focus has been given on these abnormal eye movements of Unmada. The present study aims at understanding of these abnormal eye movements mentioned in Unmada with the help of modern research and literature. Abnormal smooth pursuit eye movements, decreased pursuit gain, increased saccadic frequency, increased anticipatory saccades, and anti-saccade errors are well-documented in schizophrenia patients. It seems that ancient Indian Ayurvedic sages had tremendous observational and clinical skills by which they were able to detect abnormal eye movements in the patients suffering from various psychiatric disorders thousands of years before. Various abnormal eye movements such as smooth pursuit eye movements deficits, abnormal saccadic eye movements, and other abnormal eye movements in schizophrenia resembles with “Paryakula drishti/Chakshusho aakulata/Chakshusho apasarpanam” of Unmada. Currently available research based on abnormal eye movements in schizophrenia supports the Ayurvedic view.

The neurophysiology of biological motion perception in schizophrenia.

IntroductionThe ability to recognize human biological motion is a fundamental aspect of social cognition that is impaired in people with schizophrenia. However, little is known about the neural substrates of impaired biological motion perception in schizophrenia. In the current study, we assessed event-related potentials (ERPs) to human and nonhuman movement in schizophrenia.MethodsTwenty-four subjects with schizophrenia and 18 healthy controls completed a biological motion task while their electroencephalography (EEG) was simultaneously recorded. Subjects watched clips of point-light animations containing 100%, 85%, or 70% biological motion, and were asked to decide whether the clip resembled human or nonhuman movement. Three ERPs were examined: P1, N1, and the late positive potential (LPP).ResultsBehaviorally, schizophrenia subjects identified significantly fewer stimuli as human movement compared to healthy controls in the 100% and 85% conditions. At the neural level, P1 was reduced in the schizophrenia group but did not differ among conditions in either group. There were no group differences in N1 but both groups had the largest N1 in the 70% condition. There was a condition × group interaction for the LPP: Healthy controls had a larger LPP to 100% versus 85% and 70% biological motion; there was no difference among conditions in schizophrenia subjects.ConclusionsConsistent with previous findings, schizophrenia subjects were impaired in their ability to recognize biological motion. The EEG results showed that biological motion did not influence the earliest stage of visual processing (P1). Although schizophrenia subjects showed the same pattern of N1 results relative to healthy controls, they were impaired at a later stage (LPP), reflecting a dysfunction in the identification of human form in biological versus nonbiological motion stimuli.

Extrapyramidal symptoms and cognitive test performance in patients with schizophrenia

BackgroundMovement disorders are common in individuals with schizophrenia, even in those who are not exposed to antipsychotic medications. Extrapyramidal symptoms (EPS) are among the most common abnormal movements in schizophrenia, but their relationship with other features of the illness such as cognition is not well characterized. MethodsThree hundred and twenty-five individuals with schizophrenia who were not receiving any antipsychotic or anticholinergic medication and participated in the baseline visit of the Clinical Antipsychotic Treatment of Intervention Effectiveness study were included in the present study. EPSs were assessed using the Simpson-Angus Scale, while cognition was measured with a comprehensive neuropsychological test battery. The relationship between EPS and cognitive test performance was evaluated both dimensionally and categorically. ResultsGreater severity of EPS was significantly associated with worse cognitive test performance evaluated using a composite score. Eighty-six patients were identified as having parkinsonism and these patients performed worse on cognitive tests than non-parkinsonian patients. These findings remained significant even after accounting for other variables such as severity of psychopathology, sedation, akathisia and dyskinesia. ConclusionsThe present results demonstrate that severity of EPS is reliably linked with poorer scores on tests of cognition. While this may reflect a common pathophysiology underlying neuromotor and neurocognitive deficits, it may also be the case that parkinsonian symptoms such as rigidity and bradykinesia impede test taking ability. Regardless of mechanism, inferences regarding cognitive impairment should take into account the presence of EPS, as well as other variables that may mediate cognitive test findings.

Movement disorders in neuroleptic-naïve patients with schizophrenia spectrum disorders.

BackgroundSpontaneous Movements Disorders (SMDs) or dyskinetic movements are often seen in patients with schizophrenia and other psychotic disorders, and are widely considered to be adverse consequences of the use of antipsychotic medications. Nevertheless, SMDs are also observed in the pre-neuroleptic ear and among patients who were never exposed to antipsychotic medications. The aim of this study was to determine the extent of SMDs among antipsychotic-naïve patients in a low income setting, and to evaluate contextually relevant risk factors.MethodsThe study was a cross-sectional facility-based survey conducted at a specialist psychiatric hospital in Addis Ababa, Ethiopia. Consecutive consenting treatment-naïve patients with a diagnosis of schizophrenia, schizoaffective disorder and schizophreniform disorder contacting services for the first time were assessed using the Simpson-Angus Rating Scale (SAS) and the Abnormal Involuntary Movement Scale (AIMS) to evaluate the presence of SMDS. Scale for the Assessment of Negative Symptoms (SANS) and Scale for the Assessment of Positive Symptoms (SAPS) were administered to evaluate negative and positive symptom profiles respectively. Body mass index (BMI) was used as a proxy measure for nutritional status.ResultSixty-four patients, 67.2% male (n = 43), with first contact psychosis who met the DSM-IV-TR criteria for schizophrenia (n = 47), schizophreniform disorder (n = 5), and schizoaffective disorder (n = 12) were assessed over a two month study period. Seven patients (10.9%) had SMDs. BMI (OR = 0.6, 95% CI = 0.40, 0.89; p = 0.011) and increasing age (OR = 1.10; 95% CI = 1.02, 1.20; p = 0.017) were associated with SMD.ConclusionsThis finding supports previous suggestions that abnormal involuntary movements in schizophrenia and other psychotic disorders may be related to the pathophysiology of psychotic disorders and therefore cannot be attributed entirely to the adverse effects of neuroleptic medication.

Sleep related rhythmic movements and periodic limb movements in schizophrenia: a clinical case

Schizophrenic patients may present sleep troubles that classically include abnormality of circadian rhythm, a reduction of sleep efficiency and the electroencephalogram’s finding of reduced sleep spindles. Nevertheless we do not know the prevalence of other sleep related conditions in these patients, such as rhythmic and/or periodic limb movements. We describe a nocturnal, laboratory based, video-polysomnography (PSG) of a 36 years-old man, with a diagnosis of schizophrenia 14 years before. During his childhood he presented sleep related rhythmic movement (head banging) that progressively disappeared when he was a teenager. He was remitted to our laboratory with a clinical suspect of parasomnia, for presenting in the last months limb and arm movements, usually at the beginning of the sleep. His medications include Risperidone, Biperiden and Clorazepate. The PSG showed a reduction of sleep efficiency and the presence of polymorphic periodic and rhythmic movements during sleep. Rhythmic movements took place during the awakening and N1, with the patient in the supine position and consisted of a rhythmic external rotation of the hip (usually the left) with flexed knee. Three types of periodic movement were detected: typical limb movements with dorsal extension of the foot; forearm extension, with adduction and internal rotation of the arm; a fast extension- flexion of the forearm, as rubbing the hand together with the abdominal wall and frequently correlated with arousals. The unusual association of typical and atypical periodic movement during sleep as well as sleep related rhythmic movements suggest a possible relation with the psychiatric condition and/or the medication of the patient. Clinical staff.

Increased intra-subject reaction time variability in the volitional control of movement in schizophrenia

Increased Reaction Time (RT) studies intra-subject variability is an emerging and consistent finding in RT studies of schizophrenia. A group of 23 patients suffering from DSM-IV schizophrenia and a group of 23 age-matched control subjects performed two RT tasks requiring basic sensorimotor processing and engaging two different motor systems: the Finger Lift Reaction Time task and the Voluntary Saccade Reaction Time task. The Ex-Gaussian model was applied to the RT distributions measuring the mean (mu), and standard deviation (sigma) of a Gaussian component thought to reflect sensorimotor processing and an exponential component (tau), thought to reflect an intermediate decision process. In both tasks, a significantly larger RT intra-subject variability effectively dissociated patients from controls. RT intra-subject variability in the two tasks was highly correlated only for patients. Both sigma and tau were significantly higher in the patient group with tau being the best predictor of schizophrenia. Furthermore, only in the patient group were sigma and tau highly correlated between the two tasks. The results reflect a deficit in information processing that may not be confined to decision processes related to the frontal cortex; rather, they may indicate dysfunction in distributed neural networks modulating adaptive regulation of performance.

Eye-Head Coordination Abnormalities in Schizophrenia

BackgroundEye-movement abnormalities in schizophrenia are a well-established phenomenon that has been observed in many studies. In such studies, visual targets are usually presented in the center of the visual field, and the subject's head remains fixed. However, in every-day life, targets may also appear in the periphery. This study is among the first to investigate eye and head movements in schizophrenia by presenting targets in the periphery of the visual field.Methodology/Principal FindingsTwo different visual recognition tasks, color recognition and Landolt orientation tasks, were presented at the periphery (at a visual angle of 55° from the center of the field of view). Each subject viewed 96 trials, and all eye and head movements were simultaneously recorded using video-based oculography and magnetic motion tracking of the head. Data from 14 patients with schizophrenia and 14 controls were considered. The patients had similar saccadic latencies in both tasks, whereas controls had shorter saccadic latencies in the Landolt task. Patients performed more head movements, and had increased eye-head offsets during combined eye-head shifts than controls.Conclusions/SignificancePatients with schizophrenia may not be able to adapt to the two different tasks to the same extent as controls, as seen by the former's task-specific saccadic latency pattern. This can be interpreted as a specific oculomotoric attentional dysfunction and may support the hypothesis that schizophrenia patients have difficulties determining the relevance of stimuli. Patients may also show an uneconomic over-performance of head-movements, which is possibly caused by alterations in frontal executive function that impair the inhibition of head shifts. In addition, a model was created explaining 93% of the variance of the response times as a function of eye and head amplitude, which was only observed in the controls, indicating abnormal eye-head coordination in patients with schizophrenia.

Efference Copy Failure during Smooth Pursuit Eye Movements in Schizophrenia

Abnormal smooth pursuit eye movements in patients with schizophrenia are often considered a consequence of impaired motion perception. Here we used a novel motion prediction task to assess the effects of abnormal pursuit on perception in human patients. Schizophrenia patients (n = 15) and healthy controls (n = 16) judged whether a briefly presented moving target ("ball") would hit/miss a stationary vertical line segment ("goal"). To relate prediction performance and pursuit directly, we manipulated eye movements: in half of the trials, observers smoothly tracked the ball; in the other half, they fixated on the goal. Strict quality criteria ensured that pursuit was initiated and that fixation was maintained. Controls were significantly better in trajectory prediction during pursuit than during fixation, their performance increased with presentation duration, and their pursuit gain and perceptual judgments were correlated. Such perceptual benefits during pursuit may be due to the use of extraretinal motion information estimated from an efference copy signal. With an overall lower performance in pursuit and perception, patients showed no such pursuit advantage and no correlation between pursuit gain and perception. Although patients' pursuit showed normal improvement with longer duration, their prediction performance failed to benefit from duration increases. This dissociation indicates relatively intact early visual motion processing, but a failure to use efference copy information. Impaired efference function in the sensory system may represent a general deficit in schizophrenia and thus contribute to symptoms and functional outcome impairments associated with the disorder.

Imagined motor action and eye movements in schizophrenia

Visual exploration and planning of actions are reported to be abnormal in schizophrenia. Most of the studies monitoring eye movements in patients with schizophrenia have been performed under free-viewing condition. The present study was designed to assess whether mentally performing an action modulates the visuomotor behavior in patients with schizophrenia and in healthy controls. Visual scan paths were monitored in eighteen patients with schizophrenia and in eighteen healthy controls. Participants performed two tasks in which they were asked either to (1) look at a scene on a computer screen (free viewing), or (2) picture themselves making a sandwich in front of a computer screen (active viewing). The scenes contained both task-relevant and task-irrelevant objects. Temporal and spatial characteristics of scan paths were compared for each group and each task. The results indicate that patients with schizophrenia exhibited longer fixation durations, and fewer fixations, than healthy controls in the free viewing condition. The patients' visual exploration improved in the active viewing condition. However, patients looked less at task-relevant objects and looked more at distractors than controls in the active viewing condition in which they were asked to picture themselves making a sandwich in moving their eyes to task-relevant objects on an image. These results are consistent with the literature on deficits in motor imagery in patients with schizophrenia and it extends the impairment to visual exploration in an action imagery task.

Cortico-cerebellar functional connectivity and sequencing of movements in schizophrenia

BackgroundAbnormal execution of several movements in a sequence is a frequent finding in schizophrenia. Successful performance of such motor acts requires correct integration of cortico-subcortical processes, particularly those related to cerebellar functions. Abnormal connectivity between cortical and cerebellar regions with resulting cognitive dysmetria has been proposed as the core dysfunction behind many signs and symptoms of schizophrenia. The aim of the present study was to assess if these proposed abnormalities in connectivity are a unifying feature of schizophrenia, or, rather, reflect a specific symptom domain of a heterogeneous disease. We predicted that abnormal functional connectivity between the motor cortex and cerebellum would be linked with abnormal performance of movement sequencing.MethodsWe examined 24 schizophrenia patients (SCH) and 24 age-, sex-, and handedness-matched healthy controls (HC) using fMRI during a modified finger-tapping task. The ability to perform movement sequencing was tested using the Neurological Evaluation Scale (NES). The subjects were categorized into two groups, with (SQ+) and without (SQ-) movement sequencing abnormalities, according to the NES-SQ score. The effects of diagnosis and movement sequencing abnormalities on the functional connectivity parameters between the motor cortex and cerebellum (MC-CRBL) and the supplementary motor cortex and cerebellum (SMA-CRBL) activated during the motor task were analyzed.ResultsWe found no effect of diagnosis on the functional connectivity measures. There was, however, a significant effect on the SQ group: SQ + patients showed a lower level of MC-CRBL connectivity than SQ- patients and healthy controls. Moreover, the level of MC-CRBL and SMA-CRBL negatively correlated with the magnitude of NES-SQ abnormalities, but with no other NES domain.ConclusionsAbnormal cortico-cerebellar functional connectivity during the execution of a motor task is linked with movement sequencing abnormalities in schizophrenia, but not with the diagnosis of schizophrenia per se. It seems that specific patterns of inter-regional connectivity are linked with corresponding signs and symptoms of clinically heterogeneous conditions such as schizophrenia.

Neuroanatomical Circuitry Associated with Exploratory Eye Movement in Schizophrenia: A Voxel-Based Morphometric Study

Schizophrenic patients present abnormalities in a variety of eye movement tasks. Exploratory eye movement (EEM) dysfunction appears to be particularly specific to schizophrenia. However, the underlying mechanisms of EEM dysfunction in schizophrenia are not clearly understood. To assess the potential neuroanatomical substrates of EEM, we recorded EEM performance and conducted a voxel-based morphometric analysis of gray matter in 33 schizophrenic patients and 29 well matched healthy controls. In schizophrenic patients, decreased responsive search score (RSS) and widespread gray matter density (GMD) reductions were observed. Moreover, the RSS was positively correlated with GMD in distributed brain regions in schizophrenic patients. Furthermore, in schizophrenic patients, some brain regions with neuroanatomical deficits overlapped with some ones associated with RSS. These brain regions constituted an occipito-tempro-frontal circuitry involved in visual information processing and eye movement control, including the left calcarine cortex [Brodmann area (BA) 17], the left cuneus (BA 18), the left superior occipital cortex (BA 18/19), the left superior frontal gyrus (BA 6), the left cerebellum, the right lingual cortex (BA 17/18), the right middle occipital cortex (BA19), the right inferior temporal cortex (BA 37), the right dorsolateral prefrontal cortex (BA 46) and bilateral precentral gyri (BA 6) extending to the frontal eye fields (FEF, BA 8). To our knowledge, we firstly reported empirical evidence that gray matter loss in the occipito-tempro-frontal neuroanatomical circuitry of visual processing system was associated with EEM performance in schizophrenia, which may be helpful for the future effort to reveal the underlying neural mechanisms for EEM disturbances in schizophrenia.

Effects of adjunct valproic acid on clinical symptoms and saccadic eye movements in schizophrenia

Valproic acid (VPA) has been suggested as a potential adjunct therapy in schizophrenia for the treatment of clinical symptoms and cognitive deficits. Here, we investigate the effects of VPA on clinical symptoms and saccadic eye movements while controlling for multiple medication effects. Remitted and first-episode schizophrenia patients taking haloperidol were given adjunct VPA for approximately 2 weeks and tested using a measure of clinical symptoms (Positive and Negative Syndrome Scale) and saccadic eye movement tasks over three testing periods. The effects of VPA were compared with schizophrenia patients medicated with equivalent doses of haloperidol alone (HAL group) and normal controls. Schizophrenia patients had higher error rates on the antisaccade task (AS task) compared with normal controls. Adjunct VPA did not affect AS task error rates but was associated with an increase in response times for both saccade and AS tasks, with a significantly greater and dose-dependent increase in response times for the AS task. There were no differences in clinical improvement between VPA and HAL schizophrenia patient groups when controlling for haloperidol medication state. These results suggest that adjuvant VPA therapy results in both sensorimotor and cognitive slowing but does not either help or further impair inhibitory control in schizophrenia, as measured by the elevated AS task errors.

Measuring head movements in schizophrenia using inertial measurement

The 16th Biennial Winter Workshop in Psychoses, 30 January to 2 February 2011 Innsbruck, Austria: POSTER ABSTRACTS