Motor learning and performance in schizophrenia and aging: two different patterns of decline.

Psychomotor slowing has consistently been observed in schizophrenia, however research on motor learning in schizophrenia is limited. Additionally, motor learning in schizophrenia has never been compared with the waning of motor learning abilities in the elderly. Therefore, in an extensive study, 30 individuals with schizophrenia, 30 healthy age-matched controls and 30 elderly participants were compared on sensorimotor learning tasks including sequence learning and adaptation (both explicit and implicit), as well as tracking and aiming. This paper presents new findings on an explicit motor sequence learning task, an explicit verbal learning task and a simple aiming task and summarizes all previously published findings of this large investigation. Individuals with schizophrenia and elderly had slower Movement Time (MT)s compared with controls in all tasks, however both groups improved over time. Elderly participants learned slower on tracking and explicit sequence learning while individuals with schizophrenia adapted slower and to a lesser extent to movement perturbations in adaptation tasks and performed less well on cognitive tests including the verbal learning task. Results suggest that motor slowing is present in schizophrenia and the elderly, however both groups show significant but different motor skill learning. Cognitive deficits seem to interfere with motor learning and performance in schizophrenia while task complexity and decreased movement precision interferes with motor learning in the elderly, reflecting different underlying patterns of decline in these conditions. In addition, evidence for motor slowing together with impaired implicit adaptation supports the influence of cerebellum and the cerebello-thalamo-cortical-cerebellar (CTCC) circuits in schizophrenia, important for further understanding the pathophysiology of the disorder.

Impaired Sensorimotor Adaption in Schizophrenia in Comparison to Age-Matched and Elderly Controls.

BACKGROUND: The "cognitive dysmetria hypothesis" of schizophrenia proposes a disrupted communication between the cerebellum and cerebral cortex, resulting in sensorimotor and cognitive symptoms. Sensorimotor adaptation relies strongly on the function of the cerebellum. OBJECTIVES: This study investigated whether sensorimotor adaptation is reduced in schizophrenia compared with age-matched and elderly healthy controls. METHODS: Twenty-nine stably treated patients with schizophrenia, 30 age-matched, and 30 elderly controls were tested in three motor adaptation tasks in which visual movement feedback was unexpectedly altered. In the "rotation adaptation task" the perturbation consisted of a rotation (30° clockwise), in the "gain adaptation task" the extent of the movement feedback was reduced (by a factor of 0.7) and in the "vertical reversal task," up- and downward pen movements were reversed by 180°. RESULTS: Patients with schizophrenia adapted to the perturbations, but their movement times and errors were substantially larger than controls. Unexpectedly, the magnitude of adaptation was significantly smaller in schizophrenia than elderly participants. The impairment already occurred during the first adaptation trials, pointing to a decline in explicit strategy use. Additionally, post-adaptation aftereffects provided strong evidence for impaired implicit adaptation learning. Both negative and positive schizophrenia symptom severities were correlated with indices of the amount of adaptation and its aftereffects. CONCLUSIONS: Both explicit and implicit components of sensorimotor adaptation learning were reduced in patients with schizophrenia, adding to the evidence for a role of the cerebellum in the pathophysiology of schizophrenia. Elderly individuals outperformed schizophrenia patients in the adaptation learning tasks.

Implicit motor sequence learning in schizophrenia and in old age: reduced performance only in the third session.

Although there still is conflicting evidence whether schizophrenia is a neurodegenerative disease, cognitive changes in schizophrenia resemble those observed during normal aging. In contrast to extensively demonstrated deficits in explicit learning, it remains unclear whether implicit sequence learning is impaired in schizophrenia and normal aging. Implicit sequence learning was investigated using a computerized drawing task, the 'implicit pattern learning task (IPLT)' in 30 stable patients with schizophrenia, 30 age-matched controls and 30 elderly subjects on two consecutive days and after 1 week (sessions 1, 2 and 3). Fixed sequence trials were intermixed with random trials, and sequence learning was assessed by subtraction of the response time in fixed sequence trials from random trials. Separate analyses of response times and movement accuracy (i.e., directional errors) were performed. Explicit sequence knowledge was assessed using three different awareness tasks. All groups learned equally during sessions 1 and 2. In session 3, control subjects showed significantly larger learning scores than patients with schizophrenia (p = .012) and elderly subjects (p = .021). This group difference is mainly expressed in movement time and directional errors. Patients with schizophrenia demonstrated less subjective sequence awareness, and both patients with schizophrenia and elderly subjects had less explicit sequence recall. Explicit recall was positively correlated with task performance in all groups. After a short 24 h interval, all subjects showed similar improvements in implicit sequence learning. However, no benefit of prior task exposure 1 week later was observed in patients with schizophrenia and elderly subjects compared to controls. As patients with schizophrenia and elderly both display less explicit sequence recall, the control group superiority after 1 week could be explained by an explicit learning component. The few patients with schizophrenia and elderly subjects who had some sequence recall could possibly utilize this explicit knowledge to improve their task performance but did this by distinct mechanisms.

Unraveling psychomotor slowing in bipolar disorder.

BACKGROUND/AIMS: In addition to affective and cognitive symptomatology, psychomotor deficits are known to be present in bipolar disorder (BD). Psychomotor functioning includes all of the processes necessary for completing a movement, from planning to initiation and execution. While these psychomotor symptoms have been studied extensively in schizophrenia and major depressive disorder, only simple measures have been conducted in BD. The present study examines psychomotor functioning in BD. METHODS: Twenty-two euthymic BD patients and 21 healthy controls performed three computerized copying tasks varying in cognitive load. Movement times (MT), reflecting fine motor processing, and initiation times (IT), reflecting cognitive processing of visual-spatial information, were separately measured in each group. RESULTS: The BD patients had longer IT but not MT in the simplest task and the opposite pattern of longer MT but not IT in the complex task. However, when controlling for residual mood symptoms, the MT were no longer significantly slower in the BD group. CONCLUSIONS: The longer MT and IT in BD reflect overall psychomotor slowing. Specifically, the results provide evidence for cognitive slowing in BD. In addition, the longer MT in the complex task reflect a slowed motor component of movement when the cognitive load is high and when depressive symptoms are present. These findings extend the current knowledge of the nature of psychomotor slowing in BD and may have important prognostic implications for patients.

Longitudinal evaluation of the psychomotor syndrome in schizophrenia.

Little is known about the longitudinal course of psychomotor signs and symptoms after illness onset in schizophrenia. Therefore, a 1-year follow-up study was conducted in which patients with schizophrenia were assessed three times with an extensive battery of psychomotor rating scales and tests. The syndromic structure of psychomotor symptoms was also studied. In accordance with a neurodevelopmental view on schizophrenia, psychomotor functioning was found to remain stable or improve slightly. Prospective studies with longer follow-up periods are needed to rule out the possibility of neurodegeneration in subgroups of patients and to evaluate possible covariation in the course of psychomotor symptoms.

Affective decision-making is predictive of three-month relapse in polysubstance-dependent alcoholics.

BACKGROUND/AIMS: Common and long-lasting deficits in decision-making in polysubstance-dependent alcoholics (PSA) reflect neurobiological alterations that define the chronic nature of addiction. These deficits affect goal-directed behavior and might be critical risk factors predicting relapse in PSA. METHODS: The Delay Discounting Task (DDT) and the Iowa Gambling Task (IGT) assessed the delay-discounting and decision-making skills among 37 abstinent PSA. RESULTS: The findings indicated that IGT but not DDT performances were associated with 3-month abstinence, irrespective of the influence of personality traits and coexistent medications. CONCLUSION: The results show that the IGT, which assesses processes that are important in the latter stages of addiction, is ecologically more valid compared to the DDT, which assesses processes important in the early stages. They underline the importance of using neurocognitive measures to identify high relapse risk patients and emphasize the relevance of promoting new treatments.

Differentiation between deviant trajectory planning, action planning, and reduced psychomotor speed in schizophrenia.

INTRODUCTION: Abnormal psychomotor behaviour in schizophrenia might be based on separate deficits. Here we studied the relationship between trajectory planning, action planning, psychomotor speed, and indices of cognitive functioning in a large group of stabilised patients with schizophrenia. METHOD: Sixty-one patients and 30 controls were tested. Trajectory planning was assessed in a graphic task in which sequences of single lines, gradually changing in direction, had to be drawn. Shifts to a comfortable drawing direction reflect anticipatory trajectory planning. Action planning was evaluated in a task in which figures varying in complexity and familiarity had to be copied. Psychomotor speed was measured by use of a simple line copying task. Measures of information processing speed, attention, working memory, and problem solving were derived from neuropsychological tests. RESULTS: Patients much more often opted for the unusual bottom-to-top direction to draw the vertical lines in the drawing task. They changed the line orientation less often than the controls did. In the patient group, these trajectory planning indices did not correlate with measures of action planning, psychomotor speed, or neuropsychological test scores. CONCLUSION: Deviant trajectory planning strongly characterises schizophrenia, and is independent from action planning deficits and reduced psychomotor speed.

Spatial and nonspatial implicit motor learning in Korsakoff's amnesia: evidence for selective deficits.

Patients with amnesia have deficits in declarative memory but intact memory for motor and perceptual skills, which suggests that explicit memory and implicit memory are distinct. However, the evidence that implicit motor learning is intact in amnesic patients is contradictory. This study investigated implicit sequence learning in amnesic patients with Korsakoff's syndrome (N = 20) and matched controls (N = 14), using the classical Serial Reaction Time Task and a newly developed Pattern Learning Task in which the planning and execution of the responses are more spatially demanding. Results showed that implicit motor learning occurred in both groups of participants; however, on the Pattern Learning Task, the percentage of errors did not increase in the Korsakoff group in the random test phase, which is indicative of less implicit learning. Thus, our findings show that the performance of patients with Korsakoff's syndrome is compromised on an implicit learning task with a strong spatial response component.

Psychomotor function and response inhibition in chronic fatigue syndrome.

Most research points to cognitive slowing in chronic fatigue syndrome (CFS), although there have been negative reports. The present study is one of few that examines fine motor processing and the inhibition of automatic responses in a well-characterised CFS population. A total of 35 female CFS patients without current major depression and 25 female controls performed two computerised figure-copying tasks. The cognitive and fine motor processing of visual-spatial information was measured by recording reaction time (RT) and movement time (MT), respectively. The inhibition of automatic responses was assessed by introducing 'conflicting patterns' (i.e., patterns that were difficult to draw from the preferred left to right). A multivariate general linear model was adopted for the statistical analysis of the movement recordings. As a result, CFS was significantly associated with longer RT and MT in the pooled and in the task-specific analyses. However, there was no interaction between disease status and conflicting character of the patterns. In conclusion, these performance data on the figure-copying tasks provide confirmatory evidence for psychomotor slowing in CFS, but not for a disturbed inhibition of automatic responses. Computerised figure-copying tasks may be promising tools for use in neurobiological research and clinical trials in CFS.

How should we teach everyday skills in dementia? A controlled study comparing implicit and explicit training methods.

OBJECTIVE: To compare the immediate and delayed effects of implicit and explicit training methods for everyday skills in patients with dementia. DESIGN: Counterbalanced self-controlled cases series. SUBJECTS: Convenience sample of 10 patients with dementia (Mini-Mental State Examination score between 15 and 26) and 16 age- and education-matched controls. INTERVENTION: Two everyday tasks (using a microwave oven and a coffee machine) that were novel to all participants were trained in five 15-minute sessions. Each participant learned both tasks, one using an implicit learning method (modelling) and the other using an explicit learning method (providing verbal cues). Tasks and conditions were counterbalanced. MEASURES: The participants' performance was videotaped to assess how well the tasks were performed before training, after each training session, and 7-10 days after the final training session. A rater, who was blind to the training method used, scored the number of correctly executed steps by viewing the videotapes. RESULTS: The two training methods were effective in both the patient and healthy control groups, with there being a significant baseline-to-follow-up increase in the number of correctly completed steps (P < 0.001). There were no differences between the training methods (P = 0.16) and no significant interaction between training method and group (P = 0.31). CONCLUSIONS: Older patients with mild dementia are able to acquire new skills that are relevant for daily life, showing a similar rate of learning regardless of whether implicit or explicit learning techniques are used.

The impact of perfectionism and anxiety traits on action monitoring in major depressive disorder.

Perfectionism and anxiety features are involved in the clinical presentation and neurobiology of major depressive disorder (MDD). In MDD, cognitive control mechanisms such as action monitoring can adequately be investigated applying electrophysiological registrations of the error-related negativity (ERN) and error positivity (Pe). It is also known that traits of perfectionism and anxiety influence ERN amplitudes in healthy subjects. The current study explores the impact of perfectionism and anxiety traits on action monitoring in MDD. A total of 39 MDD patients performed a flankers task during an event-related potential (ERP) session and completed the multidimensional perfectionism scale (MPS) with its concern over mistakes (CM) and doubt about actions (DA) subscales and the trait form of the State Trait Anxiety Inventory. Multiple regression analyses with stepwise backward elimination revealed MPS-DA to be a significant predictor (R (2):0.22) for the ERN outcomes, and overall MPS (R (2):0.13) and MPS-CM scores (R (2):0.18) to have significant predictive value for the Pe amplitudes. Anxiety traits did not have a predictive capacity for the ERPs. MPS-DA clearly affected the ERN, and overall MPS and MPS-CM influenced the Pe, whereas no predictive capacity was found for anxiety traits. The manifest impact of perfectionism on patients' error-related ERPs may contribute to our understanding of the action-monitoring process and the functional significance of the Pe in MDD. The divergent findings for perfectionism and anxiety features also indicate that the wide range of various affective personality styles might exert a different effect on action monitoring in MDD, awaiting further investigation.

Psychomotor planning is deficient in recent-onset schizophrenia.

BACKGROUND: Psychomotor slowing is regarded as an important clinical phenomenon in schizophrenia and simple graphic tasks consistently revealed deficits in the (implicit) planning and execution of motor actions in patients with chronic schizophrenia. The aim of the present study is to test the hypothesis that such deficits are already present in patients with recent-onset schizophrenia. METHODS: Psychomotor performance and several aspects of movement planning were analyzed in 36 patients with recent-onset schizophrenia and a group of 33 matched healthy controls. Participants were required to draw patterns varying in complexity in three different figure-copying tasks, match and draw simple symbols in the Digit Symbol Substitution Test (DSST) and connect target circles with varying orientations in a newly developed Line Sequencing Task. RESULTS: Relative to the controls, the patients showed significantly longer initiation times when the patterns in the copying tasks became more complex, suggesting increased difficulty in movement planning. Overall, they were not slowed in the execution stages. In the cognitively more demanding DSST, the patients were significantly slowed in both the initiation and movement phases. Moreover, they selected less optimal movement directions in the Line Sequencing Task. CONCLUSIONS: Psychomotor planning deficits are already present in the early stages of schizophrenia and involve deficient planning but intact motor action. Planning difficulties can be detected in motor sequences as well. The results indicate that the cognitive deficit in schizophrenia also affects the implicit planning of very simple movements.

When the mental number line involves a delay: the writing of numbers by children of different arithmetical abilities.

Our study focused on number transcoding in children. It investigated how 9-year-olds with and without arithmetical disabilities wrote Arabic digits after they had heard them as number words. Planning time before writing each digit was registered. Analyses revealed that the two groups differed not only in arithmetical abilities but also in verbal and reading abilities. Children with arithmetical disabilities were overall slower in planning Arabic digits than were control children with normal arithmetical abilities. In addition, they showed a number size effect for numbers smaller than 10, suggesting a semantically mediated route in number processing. Control children did not need more planning time for large numbers (e.g., 8) than for small numbers (e.g., 3), suggesting a direct nonsemantic route. For both two- and three-digit numbers, both groups of children showed a number size effect, although the effect was smaller each time for control children. The presence of the stronger number size effect for children with arithmetical disabilities was seen as a delay in the development of quick and direct transcoding. The relation between transcoding problems and arithmetical disabilities is discussed. A defect in the linking of numerical symbols to analog numerical representations is proposed as an explanation for the transcoding problems found in some children.

The effects of atypical and conventional antipsychotics on reduced processing speed and psychomotor slowing in schizophrenia: a cross-sectional exploratory study.

BACKGROUND: Psychomotor slowing is an intrinsic feature of schizophrenia, but little is known about its nature or to what extent it is influenced by antipsychotics. The Symbol-Digit Substitution Test (SDST) is an appropriate tool for assessing reduced processing speed, whereas performance on copying tasks may be more useful in evaluating psychomotor slowing. OBJECTIVE: The primary aim of this study was to investigate the effects of different antipsychotic agents on psychomotor slowing in patients with schizophrenia. METHODS: This cross-sectional study compared performance on line- and figure-copying tasks in schizophrenic inpatients (matched for symptomatology, demographic variables, and duration of illness) treated with risperidone, olanzapine, other atypical antipsychotics (amisulpride, aripiprazole, clozapine, or quetiapine), or conventional antipsychotics (bromperidol, flupentixol, haloperidol, pimozide, or zuclopenthixol) and in healthy controls. Other tests administered included the SDST to assess processing speed, the California Verbal Learning Test to gauge verbal memory, the Letter-Number Sequencing task to assess working memory, and the Wisconsin Card Sorting Test to measure executive function. Comparisons were made between each patient group and healthy controls; between patient groups; and, post hoc, between atypical and conventional antipsychotics. RESULTS: The study included 26 patients treated with risperidone, 24 treated with olanzapine, 25 treated with other atypical antipsychotics, 21 treated with conventional antipsychotics, and 25 healthy controls. The groups were well matched in terms of sex, educational level, mean doses, and duration of illness. The conventional-antipsychotic group was significantly older (P=0.026) and had significantly higher positive symptoms scores (P=0.031) on the Positive and Negative Syndrome Scale compared with the risperidone group. Patients treated with conventional antipsychotics had significantly greater slowing on the copying tasks compared with patients treated with atypical antipsychotics (P

Delay-related cerebral activity and motor preparation.

Flexible goal-oriented behavior requires the ability to carry information across temporal delays. This ability is associated with sustained neural firing. In cognitive terms, this ability has often been associated with the maintenance of sensory material online, as during short-term memory tasks, or with the retention of a motor code, as during movement preparation tasks. The general issue addressed in this paper is whether short-term storage of sensory information and preparation of motor responses rely on different anatomical substrates. We used functional magnetic resonance imaging (fMRI) to measure sustained and time-varying delay-related cerebral activity evoked during performance of a delay non-match to sample (DNMS) task, where task contingencies rather than explicit instructions ensured that either sensory or motor representations were used to cross the delay period on each trial. This approach allowed us to distinguish sensory from motor characteristics of delay-related activity evoked by task contingencies, rather than differences in the control of short-term storage driven by verbal instructions. Holding sensory material online evoked both sustained and time-varying delay-related activity in prefrontal regions, whereas movement preparation evoked delay-related responses in precentral areas. Intraparietal cortex was sensitive to the presence of memoranda, but indifferent to the type of information that was retained in memory. Our findings indicate that short-term storage of sensory information and preparation of motor responses rely on partially segregated cerebral circuits. In the frontal lobe, these circuits are organized along a rostro-caudal dimension, corresponding to the sensory or motor nature of the stored material.

Action monitoring in major depressive disorder with psychomotor retardation.

Major depressive disorder (MDD) is characterized by disturbances of mood and affect, but also by a distinct pattern of psychomotor and cognitive deficits such as motor retardation and impaired executive functioning. An important aspect of executive functioning is performance monitoring, i.e., a continuous checking whether intended action goals have been reached and whether correction of the applied strategy is necessary. A well-known marker for action monitoring is the error negativity (Ne) or error-related negativity (ERN), an event-related potential (ERP) component generated in the anterior cingulate cortex (ACC) following erroneous responses. To date, Ne/ERN amplitudes have been investigated in moderately depressed patients only. The present study is the first to investigate action monitoring in severely depressed patients (mean Hamilton score=28.4). In addition, the patients' psychomotor performance was assessed to see whether there is a relationship between action monitoring and psychomotor retardation. Behavioural and ERP measurements were obtained during performance on a speeded two-choice reaction task in 26 patients with MDD and 25 healthy, matched controls. Psychomotor performance measures were speed of simple movements in various psychomotor tasks and the score on the Salpêtrière retardation rating scale (SRRS). Relative to the controls, the patients' behavioural results revealed a similar, but slower performance pattern. Overall between-group differences were demonstrated for the error positivity (Pe) amplitudes, but not for the Ne/ERN amplitudes. However, correlations of the Ne/ERN amplitude with several psychomotor variables were strong. In the depressed patients taking benzodiazepines an additional attenuation of Ne/ERN amplitudes was observed. Only severely depressed patients manifesting retardation showed impeded action monitoring. The correlations between action monitoring and psychomotor performance indicate that in MDD these two processes are highly interdependent, both being deregulated. Moreover, the same network of brain regions is likely to be implicated in both processes.

Psychomotor symptoms in depression: a diagnostic, pathophysiological and therapeutic tool.

BACKGROUND: Psychomotor disturbances have been described repeatedly over many centuries. More recently, Sobin and Sackeim [Sobin, C., Sackeim, H.A., 1997. Psychomotor symptoms of depression. Am. J. Psychiatry. 154, 4-17.] discussed the relevance of psychomotor symptoms in depression in an extensive review. Since their report, new pathophysiological, diagnostic and therapeutic findings have been published. In the current review of the recent literature, we aim to argue the importance of psychomotor symptoms in depression and propose directions for future research. METHOD: A review of all the relevant reports on this topic, published between 1996 and 2006, was conducted. RESULTS: Several assessment methods demonstrate the diagnostic and pathophysiological significance of psychomotor symptoms. Antidepressants show differential effects on psychomotor performance and findings concerning the symptoms' predictive capacity for clinical response are contradictory. Numerous imaging studies as well as studies on the neurotransmitter systems and the HPA-axis contribute to the elucidation of the neurobiological processes underlying impaired psychomotor functioning in depression. CONCLUSIONS: Psychomotor disturbances are of great diagnostic significance for the depressive subtype of melancholia. To enhance the conceptualisation of the construct 'psychomotor' a standardised battery for their assessment is recommended. As to the symptoms' predictive therapeutic power, to date research into functional outcome and studies applying objective experimental assessment methods are lacking. Moreover, the reported pathophysiological importance of dopamine for 'retarded depression' still warrants translation to the daily practice.

Bleuler revisited: psychomotor slowing in schizophrenia as part of a catatonic symptom cluster.

In schizophrenia, psychomotor slowing and stereotypy are poorly delineated from cognitive deficits like diminished processing speed. Inpatients' performance outcomes on a line-copying task, a task assessing stereotypy and a processing-speed task are compared. Results suggested that psychomotor slowing and stereotypy are related and may represent a catatonic symptom cluster.

On the programming and reprogramming of actions.

Actions are often selected in the context of ongoing movement plans. Most studies of action selection have overlooked this fact, implicitly assuming that the motor system is passive prior to presentation of instructions triggering movement selection. Other studies addressed action planning in the context of an already present motor plan, but focused mostly on inhibition of a prepotent response under fierce time pressure. Under these circumstances, inhibition of previous motor plans and selection of a new response become temporally intermingled. Here, we explore how the presence of earlier motor plans influences cerebral effects associated with action selection, separating in time movement programming, reprogramming, and execution. We show that portions of parietofrontal circuits, including intraparietal sulcus and left dorsal premotor cortex, are systematically involved in programming motor responses, their activity being indifferent to the presence of earlier motor plans. We identify additional regions recruited when a motor response is programmed in the context of an existing motor program. We found that several right-hemisphere regions, previously associated with response inhibition, might be better characterized as involved in response selection. Finally, we detail the specific role of a right precentral region in movement reprogramming that is involved in inhibiting not only actual responses but also motor representations.