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.

Are emotional action tendencies and attentional bias related to temperament dimensions in patients with borderline personality disorder?

Disturbances in emotion regulation have been identified as a core feature of patients with a borderline personality disorder (BPD). Findings of studies using experimental measures of emotion processing are mixed, which may be partially explained by the heterogeneity of the BPD population. To address this issue, we investigated differences in experimental measures of emotional action tendencies (approach-avoidance behaviour) and attentional bias to emotional stimuli in BPD subtypes. Data of the Approach-Avoidance Task (AAT) and the Emotional Stroop Task (EST) were collected in 140 BPD patients, previously clustered into four BPD subtypes based on temperament dimensions. We investigated (1) the relationship between temperament dimensions and the performance on the AAT and EST and (2) compared performance on these tasks in previous defined BPD subtypes. The results of the present study demonstrated a positive relationship between effortful control (EC) and AAT effect-scores. A higher level of EC was positively associated with a general emotional action tendency towards faces with directed gaze, even when controlling for gender, age and BPD severity. Preliminary results on the comparison of the BPD subtypes demonstrated no significant differences in AAT and EST performance. These findings emphasize the relevance of EC in emotional action tendencies in BPD patients.

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.

Cognitive and psychomotor effects of three months of escitalopram treatment in elderly patients with major depressive disorder.

BACKGROUND: Although psychomotor retardation (PR) and cognitive disfunctioning are essential symptoms of elderly depressed patients, the differential effect of treatment with an SSRI in the elderly on these symptoms has hardly got any attention in studies with objective experimental measures. Since effects appear relatively slower in elderly, this study evaluates the effect on cognitive and psychomotor functioning as compared to mood, on four points during a twelve week follow up of monotreatment with escitalopram. METHOD: 28 non-demented elderly unipolar depressive patients on 5-20mg escitalopram were compared to 20 matched healthy elderly. All participants underwent a test battery containing clinical depression measures, cognitive measures of processing speed, executive function and memory, clinical ratings of PR, and objective computerized fine motor skill-tests at the start and after 2, 6 and 12 weeks. Statistical analysis consisted of a General Linear Model (GLM) repeated measures multivariate analysis of variance of completers to compare the psychomotor and cognitive outcomes of the two groups. RESULTS: Although, apart from the significant mood effect, no interaction effects were found for the psychomotor and cognitive tasks, the means in general show a trend of differential effects in cognitive and psychomotor functions, with smaller effects and delayed timeframes and with presence of subgroups compared to mood effects. LIMITATION: Longer follow up studies are necessary to evaluate differential long term effects. CONCLUSION: In elderly, moderate effects of SSRI treatment on mood precede slow or limited effects on cognition and psychomotor retardation.

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.

Stable schizophrenia patients learn equally well as age-matched controls and better than elderly controls in two sensorimotor rotary pursuit tasks.

OBJECTIVE: To compare sensorimotor performance and learning in stable schizophrenia patients, healthy age- and sex-matched controls and elderly controls on two variations of the rotary pursuit: circle pursuit (true motor learning) and figure pursuit (motor and sequence learning). METHOD: In the circle pursuit, a target circle, rotating with increasing speed along a predictable circular path on the computer screen, must be followed by a cursor controlled by a pen on a writing tablet. In the eight-trial figure pursuit, subjects learn to draw a complex figure by pursuing the target circle that moves along an invisible trajectory between and around several goals. Tasks were administered thrice (day 1, day 2, day 7) to 30 patients with stable schizophrenia (S), 30 healthy age- and sex-matched controls (C), and 30 elderly participants (>65 years; E) and recorded with a digitizing tablet and pressure-sensitive pen. The outcome measure accuracy (% of time that cursor is within the target) was used to assess performance. RESULTS: We observed significant group differences in accuracy, both in circle and figure pursuit tasks (E < S < C, p < 0.01). Strong learning effects were found in each group. Learning curves were similar in circle pursuit but differed between groups in figure pursuit. When corrected for group differences in starting level, the learning gains over the three sessions of schizophrenia patients and age-matched controls were equal and both were larger than those of the elderly controls. CONCLUSION: Despite the reduced sensorimotor performance that was found in the schizophrenia patients, their sensorimotor learning seems to be preserved. The relevance of this finding for the evaluation of procedural learning in schizophrenia is discussed. The better performance and learning rate of the patients compared to the elderly controls was unexpected and deserves further study.

The effects of nicotine on cognition are dependent on baseline performance.

Since cholinergic neurotransmission plays a major role in cognition, stimulation of the nicotinic acetylcholine receptor may be a target for cognitive enhancement. While nicotine improves performance on several cognitive domains, results of individual studies vary. A possible explanation for these findings is that the effect of nicotine administration may be dependent on baseline cognitive function, where subjects with a suboptimal cognitive performance may benefit from nicotine, while subjects who already perform optimally may show a decline in performance after nicotinic stimulation. We conducted a double-blind randomised placebo-controlled crossover trial, examining the effects of placebo, 1, and 2mg of nicotine on cognition in young (n=16, age 18-30 years) and healthy elderly (n=16, age 60-75 years) subjects. We hypothesised that the elderly would benefit more from nicotine compared to young subjects, as normal ageing is associated with decreases in cognitive function. Attention, working memory, visual memory, information-processing speed, psychomotor function, stereotypy, and emotion recognition were assessed. Compared to the young volunteers, the elderly performed significantly worse on psychomotor function and emotion recognition in the placebo condition. Nicotine had no effect in the young volunteers and decreased performance on working memory and visual memory in the elderly. Contrary to our hypothesis, the effect of nicotine was dependent on baseline performance in both the groups, with subjects with lower baseline performance benefiting from nicotine administration, while those with higher baseline performance performed worse after nicotine administration. This suggests that subjects with lower cognitive performance, irrespective of age, may benefit from nicotine.

Preserved Learning during the Symbol-Digit Substitution Test in Patients with Schizophrenia, Age-Matched Controls, and Elderly.

OBJECTIVE: Speed of processing, one of the main cognitive deficits in schizophrenia is most frequently measured with a digit-symbol-coding test. Performance on this test is additionally affected by writing speed and the rate at which symbol-digit relationships are learned, two factors that may be impaired in schizophrenia. This study aims to investigate the effects of sensorimotor speed, short-term learning, and long-term learning on task performance in schizophrenia. In addition, the study aims to explore differences in learning effects between patients with schizophrenia and elderly individuals. METHODS: Patients with schizophrenia (N = 30) were compared with age-matched healthy controls (N = 30) and healthy elderly volunteers (N = 30) during the Symbol-Digit Substitution Test (SDST). The task was administered on a digitizing tablet, allowing precise measurements of the time taken to write each digit (writing time) and the time to decode symbols into their corresponding digits (matching time). The SDST was administered on three separate days (day 1, day 2, day 7). Symbol-digit repetitions during the task represented short-term learning and repeating the task on different days represented long-term learning. RESULTS: The repetition of the same symbol-digit combinations within one test and the repetition of the test over days resulted in significant decreases in matching time. Interestingly, these short-term and long-term learning effects were about equal among the three groups. Individual participants showed a large variation in the rate of short-term learning. In general, patients with schizophrenia had the longest matching time whereas the elderly had the longest writing time. Writing time remained the same over repeated testing. CONCLUSION: The rate of learning and sensorimotor speed was found to have a substantial influence on the SDST score. However, a large individual variation in learning rate should be taken into account in the interpretation of task scores for processing speed. Equal learning rates among the three groups suggest that unintentional learning in schizophrenia and in the elderly is preserved. These findings are important for the design of rehabilitation programs for schizophrenia.

Psychomotor retardation in elderly untreated depressed patients.

BACKGROUND: Psychomotor retardation (PR) is one of the core features in depression according to DSM V (1), but also aging in itself causes cognitive and psychomotor slowing. This is the first study investigating PR in relation to cognitive functioning and to the concomitant effect of depression and aging in a geriatric population ruling out contending effects of psychotropic medication. METHODS: A group of 28 non-demented depressed elderly is compared to a matched control group of 20 healthy elderly. All participants underwent a test battery containing clinical depression measures, cognitive measures of processing speed, executive function and memory, clinical ratings of PR, and objective computerized fine motor skill-tests. Statistical analysis consisted of a General Linear Method multivariate analysis of variance to compare the clinical, cognitive, and psychomotor outcomes of the two groups. RESULTS: Patients performed worse on all clinical, cognitive, and PR measures. Both groups showed an effect of cognitive load on fine motor function but the influence was significantly larger for patients than for healthy elderly except for the initiation time. LIMITATIONS: Due to the restrictive inclusion criteria, only a relatively limited sample size could be obtained. CONCLUSION: With a medication free sample, an additive effect of depression and aging on cognition and PR in geriatric patients was found. As this effect was independent of demand of effort (by varying the cognitive load), it was apparently not a motivational slowing effect of depression.

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.

Acute nicotine improves social decision-making in non-smoking but not in smoking schizophrenia patients.

Schizophrenia patients are characterized by severe social impairments. Recently, social cognition has been put forward as an important mediator in schizophrenia between the often-reported neurocognitive deficits and functional outcome and is thus an important target for treatments. Nicotine has been reported to improve neurocognitive processes in schizophrenia patients but no studies have investigated possible nicotine-induced facilitation of social cognition. The current placebo-controlled crossover study aimed at bridging this gap by investigating whether the administration of active (1 mg or 2 mg) or placebo oromucosal nicotine spray resulted in improved social decision-making in non-smoking (N = 15) and smoking (N = 16) schizophrenia patients. All patients played the role of responder in a variant of the ultimatum game that allowed detailed measurements of fairness and intentionality considerations. The results showed impaired social decision-making in the non-smoking patients under placebo, but not in the smoking patients. Interestingly, this impairment normalized after administration of 1 mg of nicotine, but not after 2 mg of nicotine. Nicotine had no effect on performance in the smoking patients. The present study indicates that nicotine improves social decision-making in non-smoking patients. The present results suggest that acute nicotine effects may result in a facilitation of proactive control through improved attentional processes. However, the efficacy seems limited and although nicotine may thus be an interesting target for (social) cognitive enhancement in the subset of patients that do not smoke, more research is needed on the long-lasting effects of nicotine-based treatments.

Risky Decision-Making but Not Delay Discounting Improves during Inpatient Treatment of Polysubstance Dependent Alcoholics.

BACKGROUND: High levels of impulsivity, characteristics of addicted patients, are known to be important predictors of relapse. However, so far, little is known about the stability or variability of two main components of impulsivity (delay discounting and decision-making). The present study examined the changes in impulsivity during the first week of an abstinence based, behavioral orientated inpatient treatment program. METHOD: Thirty-seven polysubstance dependent alcoholics completed the Delay Discounting Task (DDT), and the Iowa Gambling Task (IGT) using the original version with decks A'B'C'D', and an alternative version with decks K'L'M'N', for measuring decision-making, after 2 and 6 weeks of active treatment. RESULTS: It was found that performances on the IGT changed during treatment while performances on the DDT did not (test-retest period: 4 weeks). CONCLUSION: The results provide preliminary evidence that improvements in decision-making might be related to treatment effects. All patients followed a highly structured cognitive-behavioral treatment program, which might have enhanced their executive functioning (coping skills training).

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.

Towards a solution for performance related confounds: frontal, striatal and parietal activation during a continuous spatiotemporal working memory manipulation task.

Working memory plays a role in various forms of psychopathology. However, working memory consists of multiple theoretical components that may be differently taxed by various specific types of task, and brain activation differences between patients and healthy controls may result from differences in task performance. This makes it difficult to interpret such results in terms of disease-related dysfunctions in affected regions or networks. The aim of the current study was to determine the brain activation related to the updating of spatiotemporal content of working memory, in such a way that performance-related confounds in future clinical studies would be minimized. Nineteen healthy volunteers performed a task involving a continuous updating process during fMRI measurement. A frontostriatal network including medial and lateral prefrontal cortex, inferior frontal cortex, premotor cortex, supplementary motor cortex, thalamus and putamen was found to be related to the updating process. The results constrain the set of brain regions plausibly related to the specific updating component of working memory. Further, the task design may be of use in future studies of pathological conditions such as schizophrenia due to the minimization of potential confounds.

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.

Relapse in pathological gamblers: A pilot study on the predictive value of different impulsivity measures.

Backgrounds and aims Pathological gambling, a common psychiatric disorder, has many similarities with substance use disorders. Relapse, an important element in addictive disorders, however, has seldom been studied in pathological gambling. Hence, in analogy with previous research studies examining the role of self-report and neurocognitive measures on relapse in substance dependent patients, the present pilot study was executed. Methods Twenty-two pathological gamblers and 31 healthy controls took part in this research. They filled in self-report questionnaires measuring impulsive personality (Barratt Impulsiveness Scale, Sensitivity to Punishment and Sensitivity to Reward Questionnaires) and performed neurocognitive tasks measuring impulsivity, decision-making and attentional bias (Iowa Gambling Task, Delay Discounting Task, Stroop Gambling Task). Twelve months later gambling activity was re-examined. Results Analyses showed that PGs who relapsed (n = 13) did not differ on self-report and neurocognitive measures of impulsivity with PGs who did not relapse (n = 9). However, both groups did differ in age at onset. Finally, healthy controls and PGs differed in some (Barratt Impulsiveness Scale, Stroop Gambling Task), but not all impulsivity measures (Delay Discounting Task, Iowa Gambling Task, Sensitivity to Punishment and Sensitivity to Reward Questionnaires). Conclusions One-year relapse in pathological gamblers is not predicted by self-report and or neurocognitive measures of impulsivity and decision-making. The similarities in performances between pathological gamblers and healthy controls illustrate the relative health of the examined pathological gamblers. This last finding supports the idea that subtypes of pathological gamblers exist so that different treatment strategies might be necessary.

Implicit motor sequence learning in children with learning disabilities: deficits limited to a subgroup with low perceptual organization.

This study tested whether deficiencies in implicit motor sequence learning occurred exclusively in a subgroup of children with learning disabilities (LD). An experimental motor sequence task showed that LD children with low Perceptual Organization did not learn the sequence through implicit training, whereas they improved considerably after a few explicit test trials. In contrast, children with low Freedom From Distractibility (or sequencing) experienced the same benefit from implicit training as the control children. These results suggest that training motor skills (e.g., writing) should be adapted to suit the visuospatial abilities of a child with LD.

Motor sequence learning in children with spina bifida.

Cognitive and motor problems are common in children with spina bifida (SB), particularly in those children with cerebral malformations (SBM). Little is known about how these conditions affect motor learning. This study examines motor sequence learning in children with SB, SBM, and healthy controls. Assessment consisted of neuropsychological tests, a simple drawing task, and a spatial motor sequence learning task. Implicit motor learning was unaffected in children with SB(M), and their sequence learning ability was also similar to that of controls. However, both groups (SB and SBM) showed impaired motor performance. The role of cerebellar malformation with SB(M) is discussed.