Association between motor timing and treatment outcomes in patients with alcohol and/or cocaine use disorder in a rehabilitation program.

BACKGROUND: Individuals with Substance Use Disorders (SUDs) have disruptions in the brain's dopaminergic (DA) system and the functioning of its target neural substrates (striatum and prefrontal cortex). These substrates are important for the normal processing of reward, inhibitory control and motivation. Cognitive deficits in attention, impulsivity and working memory have been found in individuals with SUDs and are predictors of poor SUD treatment outcomes and relapse in alcohol and cocaine dependence specifically. Furthermore, the DA system and accompanying neural substrates play a key role in the timing of motor acts (motor timing). Motor timing deficits have been found in DA system related disorders and more recently also in individuals with SUDs. Motor timing is found to correlate with attention, impulsivity and working memory deficits. To our knowledge motor timing, with regards to treatment outcome and relapse, has not been investigated in populations with SUDs. METHODS/DESIGN: This study aims to investigate motor timing and its relation to treatment response (at 8 weeks) and relapse (at 12 months) in cocaine and/or alcohol dependent individuals. The tested sensitivity values of motor timing parameters will be compared to a battery of neurocognitive tests, owing to the novelty of the motor task battery, the confounding effects of attention and working memory on motor timing paradigms, and high impulsivity levels found in individuals with SUDs. DISCUSSION: This research will contribute to current knowledge of neuropsychological deficits associated with treatment response in SUDs and possibly provide an opportunity to individualize and modify currently available treatments through the possible prognostic value of motor task performance in cocaine and/or alcohol dependent individuals.

[An imbalance between drive and guidance. A new model for the pathogenesis of schizophrenia]. / Een disbalans tussen kracht en sturing. Een nieuw model voor de pathogenese van schizofrenie.

BACKGROUND: We still do not know how genetic and environmental factors cause schizophrenia. The pathogenesis of this illness is unknown. AIM: To develop a pathogenetic model that has greater explanatory power than the existing hypotheses concerning schizophrenia. METHOD: We searched the literature with the help of Medline (from 1966) using the search terms 'schizophrenia', 'basal ganglia', 'striatum' and 'cerebellum'. We also consulted recent manuals on schizophrenia, evolutionary psychiatry and neuroanatomy. RESULTS: The analysis showed that during the phylogenesis and ontogenesis of the brain two mechanisms, which are primarily motor-control mechanisms, are applied to the intentional level of functioning; one of these initiates and delivers power to intentions (the drive mechanism), whereas the other steers and guides intentions (the guidance mechanism). As a result of the repeated application of these two mechanisms an imbalance to the detriment of the drive mechanism in the end manifests itself as schizophrenia. The model clarifies the clinical and epidemiological findings and the course of the illness. CONCLUSION: The model provides a more comprehensive explanation for existing clinical and epidemiological data than do current alternatives. The model is compliable with the main prevailing views of psychiatrists on schizophrenia and it places the genesis of schizophrenia in an evolutionary perspective.

[Psychomotor retardation in depression assessed by visuomotor tasks. Overview and achievements of ten years' research]. / Psychomotorische vertraging bij depressie, gemeten met visuomotorische taken. Overzicht en plaatsbepaling van tien jaar onderzoek.

BACKGROUND: A new line of research into psychomotor retardation in patients with a major depressive disorder began about ten years ago. The purpose of the research was twofold: to obtain a clearer understanding of psychomotor retardation in patients with a major depressive disorder and to assess the importance of psychomotor retardation for the diagnosis and treatment. AIM: To present an overview of the results of these studies in which psychomotor retardation of these patients was investigated. METHOD: The patients had to perform visuomotor tasks involving pen movements. The psychomotor retardation was measured by recording their pen movements objectively and accurately by means of a computer and digitiser. RESULTS: Patients with major depressive disorder showed pronounced psychomotor retardation in the visuomotor tasks. The psychomotor retardation appeared to be of both a cognitive and motor nature. The treatment study which examined the effect of fluoxetine on psychomotor retardation revealed that the cognitive retardation disappeared but the motor retardation remained. It was particularly the more retarded patient who responded well to fluoxetine. The research that compared the psychomotor retardation in various subtypes of depression revealed that patients with major depressive disorder showed pronounced retardation but dysthymic patients did not show any retardation. Psychomotor retardation was more severe in patients with major depressive disorder with melancholic features. CONCLUSION: Psychomotor retardation can play an important role in the diagnosis and treatment of depressive disorders.

Haloperidol and cognitive shifting.

In this study haloperidol appeared to affect the performance on a selected category of cognitive tasks considered to represent shifting aptitude. A pretest--post-test design was used with two groups of subjects: 17 patients suffering from idiopathic spasmodic torticollis, and 17 controls who were matched for age and intelligence. The results are discussed in relation to previous findings on haloperidol and cognition, shifting disorder in Parkinson's disease and changes in behavioural organization found in animals with an experimentally induced dopaminergic hypoactivity.

Psychomotor slowing and planning deficits in schizophrenia.

The relative contribution of cognitive and motor processing to psychomotor slowing in schizophrenia was investigated using three tasks: a simple line-copying task and a more complex figure-copying task, both following a reaction paradigm, and a standard psychomotor test, the Digit Symbol Test (DST). Various movement variables of the task performances were derived from recordings made with the aid of a digitizing tablet. The patients with schizophrenia appeared to be about one-third slower in their total performance time on all three tasks when compared with healthy controls, which suggests a general psychomotor slowing in this group. When itemized over the various movement variables, this slowing was found in both initiation time and movement time in the copying tasks and in the DST in the time to match the symbol and the digit, but not in writing the digit. Furthermore, in the figure-copying task it was found that increased figure complexity or decreased familiarity prolonged the initiation time. These latency increases were not significantly larger for the schizophrenia group as a whole, but only for a subgroup of patients with higher scores on negative symptoms. Regarding reinspection time, the effects of familiarity were larger in the schizophrenia group as a whole. These group findings suggest that patients tend to plan their actions less in advance, which, in the case of the more complex or unfamiliar task conditions, is a less sophisticated planning strategy. Given the longer latencies in patients with more severe negative symptoms, it seems that these patients have problems with turning a plan into action. The present study provides evidence of psychomotor slowing and planning deficits in schizophrenia.

Differentiation of cognitive and motor slowing in the Digit Symbol Test (DST): differences between depression and schizophrenia.

Schizophrenia and depression have an overlap in symptomatology, namely a slowing in both motor and mental activities, denoted in depression as 'psychomotor retardation' and in schizophrenia as 'psychomotor poverty'. By means of a new technique that allows the measurement of psychomotor speed and the computerized analysis of writing movements recorded during the performance of the Digit Symbol Test, it indeed proved to be possible to observe a slowing in both disorders. In addition, a different structure of slowing in the two patient groups could be identified.

Spasmodic torticollis: the problem of pathophysiology and assessment.

In 17 patients with idiopathic spasmodic torticollis (ST) quantitative indices for both signs (extent and direction of the head deflexions) and complaints (of deflexion, shaking and pain) were collected. In the literature deflexion in the horizontal plane is most frequently considered, but analysis of the data shows that deflexion in the coronal and sagittal planes is also important. Furthermore, it is found that especially the deflexions in the coronal and sagittal plane covariate with the patients' complaints, but not with horizontal deflexion. On the basis of these and related data, it is suggested that we are dealing with at least two subtypes of ST. Finally, the patient's neuroticism and depression scale values are within the normal range and do not show significant correlations with ST duration. The present study provides no evidence that ST is a psychogenic disorder. ST should be regarded as a central nervous system disorder of unknown aetiology.

Figure drawing and psychomotor retardation: preliminary report.

Psychomotor retardation, a general slowing of activity which is one of the central characteristics of depression, was investigated by measuring reaction time and movement duration in drawing tasks. Twenty depressive patients and 20 normal controls participated in two tasks in which either simple or more complex figures had to be copied as fast as possible on a digitizer. In general, patients needed more time to complete the drawing tasks than controls, and they performed them differently. Six patients, who could be tested before and after treatment, showed changes in drawing speed that correlated with clinical improvement. These results suggest that psychomotor retardation might be fruitfully studied by measuring the kinematic aspects of drawing and might provide objective parameters to measure progress in therapy.

The abnormal development of drive and guidance mechanisms in the brain: the pathogenesis of schizophrenia.

BACKGROUND: It remains a mystery as to how genetic and environmental factors cause schizophrenia. OBJECTIVE: To develop a pathophysiological model of schizophrenia that has greater explanatory power than existing hypotheses of the disorder. METHOD: Published findings on schizophrenia are integrated with more recent data from human and animal studies of striatal and cerebellar functions. RESULTS: The analysis shows that during phylo- and ontogenesis two primarily motor-control mechanisms are applied at the intentional (limbic) level of functioning to organize emotional and cognitive behavior: one for initiating and dosing (drive) and the other for the representational guidance (guidance) of both movements and intentions. The intentional drive and guidance mechanisms are organized through a ventral, respectively, a dorsal cortical-subcortical circuitry. CONCLUSIONS: A deficient implementation of these mechanisms at the limbic domain manifests itself as schizophrenia, whereby the heterogeneity in symptomatology is explained by the extent of the remaining cerebral activity and by the degree of indirect activation of these systems. In general, activation manifests itself as positive symptomatology and the absence of such activation as negative symptomatology. The model provides a more comprehensive explanation for existing clinical and epidemiological data than do the current alternatives. It is compatible with the major prevailing views on the illness, such as the theories that regard this as a progressive neurodevelopmental, or a connectivity disorder, or one resulting from a deficient cerebral lateralization, or an interrupted cortico-thalamo-cerebello-cortical circuitry. The model fits with recent theories in evolutionary psychology and evolutionary psychiatry.

Vestibular hyperreactivity in patients with idiopathic spasmodic torticollis.

Ocular motor tests performed on 14 patients with idiopathic spasmodic torticollis were normal. The vestibulo-ocular reflex tested in eight patients showed a significant high level in seven. It is suggested that this phenomenon is secondary rather than the cause of spasmodic torticollis.

Antipsychotics, movement disorders and fine motor performances: new device for the measurement of bradykinesia and tremor.

This article reviews the results of an exploratory study on the relationship between the ratings of bradykinesia, obtained by the Schedule for the Assessment of Drug-Induced Movement Disorders (SADIMoD), and the performances on writing and drawing tasks. The pen movements made during these tasks were recorded by means of an electronic digitizing tablet, a special electronic pen and a personal computer. This study was aimed at finding objective parameters for the severity of (antipsychotic-induced) bradykinesia. The results show that the writing tablet device is appropriate at finding movement variables that are related to the clinical ratings for bradykinesia: high scores for bradykinesia involved slowing on a number of duration measures during the execution of the writing and drawing tasks. We were also able to measure (postural) tremor by means of the writing tablet. However, an accelerometer seems to be more appropriate in this respect.