Impaired sequential and partially compensated probabilistic skill learning in Parkinson's disease

The striatal dopaminergic dysfunction in Parkinson's disease (PD) has been associated with deficits in skill learning in numerous studies, but some of the findings remain controversial. Our aim was to explore the generality of the learning deficit using two widely reported skill learning tasks in the same group of Parkinson's patients. Thirty-four patients with PD (mean age: 62.83 years, SD: 7.67) were compared to age-matched healthy adults. Two tasks were employed: the Serial Reaction Time Task (SRT), testing the learning of motor sequences, and the Weather Prediction (WP) task, testing non-sequential probabilistic category learning. On the SRT task, patients with PD showed no significant evidence for sequence learning. These results support and also extend previous findings, suggesting that motor skill learning is vulnerable in PD. On the WP task, the PD group showed the same amount of learning as controls, but they exploited qualitatively different strategies in predicting the target categories. While controls typically combined probabilities from multiple predicting cues, patients with PD instead focused on individual cues. We also found moderate to high correlations between the different measures of skill learning. These findings support our hypothesis that skill learning is generally impaired in PD, and can in some cases be compensated by relying on alternative learning strategies.     

Frontal deficits differentiate progressive supranuclear palsy from Parkinson's disease

The clinical differentiation of progressive supranuclear palsy from Parkinson's disease can be challenging, due to overlapping clinical features and a lack of diagnostic markers. Abnormalities in cognitive function form part of the clinical spectrums of these diseases and distinctive cognitive profiles may be helpful in differentiating these diseases in the diagnostic period. A comprehensive neuropsychological test battery was administered to 12 patients with clinically diagnosed progressive supranuclear palsy and 12 patients with Parkinson's disease matched for age and disease duration. Effect size (Cohen's d) was calculated for cognitive tests that were significantly different between groups. Patients with progressive supranuclear palsy performed significantly worse than those with Parkinson's disease on measures of processing speed, verbal fluency, planning, verbal abstract reasoning, verbal memory, and made more perseverative responses on a set shifting task. Measures of executive function, manual dexterity and processing speed were most diagnostically useful (Cohen's d > 2.0) in differentiating between progressive supranuclear palsy and Parkinson's disease. These findings suggest that more severe and prominent ‘frontal’ cognitive deficits in patients with progressive parkinsonism would be helpful in predicting progressive supranuclear palsy rather than Parkinson's disease and these findings may contribute to the development of diagnostic criteria.     

Effect of click trains on duration estimates by people with Parkinson's disease

Patients with a diagnosis of Parkinson's disease and age- and IQ-matched controls estimated the duration of short 500-Hz tones (325–1,225 ms), on trials where the tone was either preceded by 3 s of 5-Hz clicks, or presented without clicks. The click manipulation had been shown in earlier studies with student participants to make verbal estimates longer. Patients were tested both on and off their dopaminergic medication, and controls were also tested in two sessions. Verbal estimates were markedly and significantly longer on trials with clicks than on those without clicks for both the patients and the controls, but there were no significant performance differences between patients or controls, nor between the on and off medication sessions in the patients. The study shows that a manipulation of subjective time, which has had small but consistent effects in student participants, also affects timing in patients and adds to a growing body of evidence that timing in patients with Parkinson's disease may in many cases have the same characteristics as those of neurologically intact control groups.     

Proprioception and Motor Control in Parkinson's Disease

ABSTRACT

Parkinson's disease (PD) is a neurodegenerative disorder that leads to a progressive decline in motor function. Growing evidence indicates that PD patients also experience an array of sensory problems that negatively impact motor function. This is especially true for proprioceptive deficits, which profoundly degrade motor performance. This review specifically address the relation between proprioception and motor impairments in PD. It is structured around 4 themes: (a) It examines whether the sensitivity of kinaesthetic perception, which is based on proprioceptive inputs, is actually altered in PD. (b) It discusses whether failed processes of proprioceptive-motor integration are central to the motor problems in PD. (c) It presents recent findings focusing on the link between the proprioception and the balance problems in PD. And (d) it discusses the current state of knowledge of how levodopa medication and deep brain stimulation affect proprioceptive and motor function in PD. The authors conclude that a failure to evaluate and to map proprioceptive information onto voluntary and reflexive motor commands is an integral part of the observed motor symptoms in PD.     

Processing of proprioceptive information in Parkinson's disease patients

The present study is concerned with a comparison of Parkinson's disease patients and normal subjects on a number of simple and choice reaction time tasks in accordance with Sternberg's interactive procedures. The results indicated that the motor disorder in Parkinson's disease was at the level of output processing and related to the inability of central mechanisms to select and organize responses. Further, the results suggested that patients had difficulty in formulating complex plans or programmes for action.     

Retention of Implicit Sequence Learning in Persons Who Stutter and Persons With Parkinson's Disease

ABSTRACT. The authors investigated the retention of implicit sequence learning in 14 persons with Parkinson's disease (PPD), 14 persons who stutter (PWS), and 14 control participants. Participants completed a nonsense syllable serial reaction time task in a 120-min session. Participants named aloud 4 syllables in response to 4 visual stimuli. The syllables formed a repeating 8-item sequence not made known to participants. After 1 week, participants completed a 60-min retention session that included an explicit learning questionnaire and a sequence generation task. PPD showed retention of general learning equivalent to controls but PWS's reaction times were significantly slower on early trials of the retention test relative to other groups. Controls showed implicit learning during the initial session that was retained on the retention test. In contrast, PPD and PWS did not demonstrate significant implicit learning until the retention test suggesting intact, but delayed, learning and retention of implicit sequencing skills. All groups demonstrated similar limited explicit sequence knowledge. Performance differences between PWS and PPD relative to controls during the initial session and on early retention trials indicated possible dysfunction of the cortico-striato-thalamo-cortical loop. The etiological implications for stuttering, and clinical implications for both populations, of this dysfunction are discussed.     

Relationships between movement initiation times and movement-related cortical potentials in Parkinson's disease

Movement-related cortical potentials recorded from the scalp reveal increasing cortical activity occurring prior to voluntary movement. Studies of set-related cortical activity recorded from single neurones within premotor and supplementary motor areas in monkeys suggest that such premovement activity may act to prime activity of appropriate motor units in readiness to move, thereby facilitating the movement response. Such a role of early stage premovement activity in movement-related cortical potentials was investigated by examining the relationship between premovement cortical activity and movement initiation or reaction times. Parkinson's disease and control subjects performed a simple button-pressing reaction time task and individual movement-related potentials were averaged for responses with short compared with long reaction times. For Parkinson's disease subjects but not for the control subjects, early stage premovement cortical activity was significantly increased in amplitude for faster reaction times, indicating that there is indeed a relationship between premovement cortical activity amplitude and movement initiation or reaction times. In support of studies of set-related cortical activity in monkeys, it is therefore suggested that early stage premovement activity reflects the priming of appropriate motor units of primary motor cortex, thereby reducing movement initiation or reaction times.PsycINFO classification: 2330; 2520; 2530     

Verbal Implicit Sequence Learning in Persons Who Stutter and Persons With Parkinson's Disease

The authors investigated the integrity of implicit learning systems in 14 persons with Parkinson's disease (PPD), 14 persons who stutter (PWS), and 14 control participants. In a 120-min session participants completed a verbal serial reaction time task, naming aloud 4 syllables in response to 4 visual stimuli. Unbeknownst to participants, the syllables formed a repeating 8-item sequence. PWS and PPD demonstrated slower reaction times for early but not late learning trials relative to controls reflecting delays but not deficiencies in general learning. PPD also demonstrated less accuracy in general learning relative to controls. All groups demonstrated similar limited explicit sequence knowledge. Both PWS and PPD demonstrated significantly less implicit sequence learning relative to controls, suggesting that stuttering may be associated with compromised functional integrity of the cortico-striato-thalamo-cortical loop.     

Evaluating the Acute Contributions of Dopaminergic Replacement to Gait With Obstacles in Parkinson's Disease

The influence of dopaminergic replacement (DR) on gait in people with Parkinson's disease (PD) is well documented. However, little is known about the acute effects of dopamine on more complex locomotor tasks that require visual guidance to avoid obstacles during gait. The authors investigated the influence of DR on locomotor behavior in a task where movement planning and control might be challenged by the height of the obstacle. The PD group included patients diagnosed with idiopathic PD (n = 12), as well as healthy controls (n = 12). Patients walked and stepped over obstacles of different heights before (OFF) and after (ON) levodopa intake. Spatial adjustments were not modulated by DR, but the step time to perform these anticipatory gait adjustments was longer only in PD-OFF (compared with healthy controls) when approaching the highest obstacle, but not PD-ON. During the crossing phase, trail limb toe clearance of PD patients was shorter than healthy controls only during the OFF state. ON-OFF comparisons were significantly different only for the time to reach the lead foot clearance over the highest obstacle. In summary, DR partially improved movement slowness but did not directly affect movement amplitude of lower limb regulation in this gait task.     

Evidence of Incomplete Motor Programming in Parkinson's Disease

One of the essential questions regarding movement deficits in Parkinson's disease (PD) is whether they stem from impaired selecting and switching among movements, impaired use of predictive information to prepare movement, or impaired execution of movement. PD subjects (n = 9) and age-matched control subjects (n = 8) performed a cued, sequential-response RT task. The cue provided either no information, accurate information, or inaccurate information about the upcoming response. PD subjects used predictive information to prepare and to switch among movement sequences normally, but second and third key press latencies were prolonged in comparison with the first key press latency. In Experiments 2 and 3, the effects of choice set and sequence length on key press latencies were examined. These results provide evidence that PD subjects initiate movement before the entire response sequence is prepared. PD does not impair motor programming or execution processes themselves but impairs the smooth coordination of those processes.     

The predictive relationships between advanced dynamic balance and physical activity/quality of life in Parkinson's disease

Gait and balance problems commonly occur in Parkinson's disease (PD). However, balance tasks with only one performance objective (e.g., sit-to-stand) may not be sufficient, compared to dual motor tasks (e.g., carrying a tray while walking), to be applied to the assessments and interventions which are designed to promote PD patients' balance functioning, physical activity (PA) and health-related quality of life (HQoL). The aim of this study, therefore, was to determine whether advanced dynamic balance, measured by a demanding motor-motor dual task, is a significant predictor of PA/HQoL in older adults with and without PD. Participants with (n = 22) and without (n = 23) PD were assessed using the Berg Balance Scale (BBS), the single leg hop and stick series task (SLHS), the Physical Activity Scale for the Elderly (PASE), and the Parkinson's Disease Questionnaire–39 (PDQ39). We calculated the R² change, namely the incremental validity, between the multiple regression models before and after adding the scores on the BBS/SLHS. While controlling for biological and socioeconomic covariates, competence in the SLHS task provided moderate and large levels of incremental validity to PA (ΔR² = 0.08, Cohen's f² = 0.25, p = .035) and HQoL (ΔR² = 0.13, Cohen's f² = 0.65, p < .001), respectively. In particular for participants with PD, the SLHS explained significantly more variance in HQoL in relation to psychosocial functioning (ΔR² = 0.25, Cohen's f² = 0.42, p = .028) compared to the BBS (p = .296). Assessing advanced dynamic balance by means of a highly demanding dual-task paradigm was not only strongly associated with PA but also covered a wider spectrum of HQoL components. This approach is recommended for use in evaluations and interventions carried out in clinical and research settings in order to promote healthy living.     

Transcranial direct-current stimulation enhances implicit motor sequence learning in persons with Parkinson's disease with mild cognitive impairment

Implicit motor sequence learning (IMSL) is affected in Parkinson's disease (PD). Research in healthy young participants shows the potential for transcranial direct-current stimulation (tDCS) over the primary motor cortex (M1) to enhance IMSL. In PD, only null effects have been reported to date. We determined concurrent, short-term, and long-term effects of anodal tDCS over M1 on IMSL, as measured by the serial reaction time (SRT) task, in persons with PD with mild cognitive impairment (MCI). Concurrent (anodal/sham tDCS intervention during the SRT task), short-term (5 min post-intervention), and long-term (1 week post-intervention) effects on IMSL were evaluated in persons with idiopathic PD (Hoehn and Yahr stage II-III) with MCI. Results of 11 persons with PD (8 men and 3 women; mean age = 77.1 years; mean disease duration = 7.7 years) showed significant IMSL in the anodal (p = .016), but not in the sham tDCS condition (p = .937). Post-hoc analyses showed that IMSL reached statistical significance at 1 week post-intervention (p < .001). Anodal tDCS over M1 exerted beneficial effects on IMSL in persons with PD with MCI, in particular one week post-intervention. Our study is the first to report a positive effect of tDCS on IMSL in PD. Further research should include a larger, more cognitively diverse sample and additional follow-up periods.     

Interference Effects from Observed Movement in Parkinson's Disease

Previous research has demonstrated that Parkinson's disease patients have an increased susceptibility to response conflict. In the present study, the authors investigate whether Parkinson's patients have a similar sensitivity to interference from observed movements. In all, 10 patients and 10 controls performed horizontal and vertical arm movements while watching a video of either a person performing similar movements or a moving dot. Movements were performed in the same plane (congruent) and orthogonal to the observed movement (incongruent). The off-axis variance of movements was our index of interference. Although patients tended to exhibit more off-axis variability than did controls, both groups demonstrated similar congruence effects, with greater variance in incongruent conditions. These results indicated that increased susceptibility to interference in Parkinson's disease does not extend to interference from observed movements.     

The Role of Recollection and Familiarity in Nondemented Parkinson's Patients

The aim of the current study was to examine if recollection and familiarity decline in nondemented Parkinson's patients. To do so we compared a sample of older people with Parkinson's disease (n = 32) to a control sample of healthy older people (n = 32) on an associative recognition task in which we manipulated the repetition of the pairs during the study phase (half of the pairs were presented once and half twice) to obtain corrected estimates of recollection, familiarity, and false recognition based on the logic of the process-dissociation procedure. The results clearly show that recollection is impaired but familiarity is preserved in nondemented Parkinson's patients. The results show that memory for pairs in Parkinson's patients relies largely on the familiarity of each item and not on a precise recollection of associative information, supporting the idea that recollection-based monitoring processes are impaired in these patients.     

Children benefit differently from night- and day-time sleep in motor learning

Motor skill acquisition occurs while practicing (on-line) and when asleep or awake (off-line). However, developmental questions still remain about whether children of various ages benefit similarly or differentially from night- and day-time sleeping. The likely circadian effects (time-of-day) and the possible between-test-interference (order effects) associated with children's off-line motor learning are currently unknown. Therefore, this study examines the contributions of over-night sleeping and mid-day napping to procedural skill learning. One hundred and eight children were instructed to practice a finger sequence task using computer keyboards. After an equivalent 11-h interval in one of the three states (sleep, nap, wakefulness), children performed the same sequence in retention tests and a novel sequence in transfer tests. Changes in the movement time and sequence accuracy were evaluated between ages (6–7, 8–9, 10–11 years) during practice, and from skill training to retrievals across three states. Results suggest that night-time sleeping and day-time napping improved the tapping speed, especially for the 6-year-olds. The circadian factor did not affect off-line motor learning in children. The interference between the two counter-balanced retrieval tests was not found for the off-line motor learning. This research offers possible evidence about the age-related motor learning characteristics in children and a potential means for enhancing developmental motor skills. The dynamics between age, experience, memory formation, and the theoretical implications of motor skill acquisition are discussed.     

A Comparison of Effectiveness of Dohsa‐hou and the Alexander Technique on Happiness,Social Adjustment,Hope, Mental Health,and Quality of Life in Patients with Parkinson's Disease

The purpose of this study was to compare the effectiveness of Dohsa‐hou and the Alexander Technique on happiness, social adjustment, hope, mental health, and quality of life in patients with Parkinson's disease. The statistical population of this study included all of the patients with Parkinson's disease who were clients of neural therapeutic centers in Isfahan City in 2015. Among this population, 28 patients were selected through convenience sampling as the sample of the study. The Oxford Happiness Questionnaire, the Social Adjustment Scale, the Adult Hope Scale, the General Health Questionnaire, and the Word Health Quality of Life Questionnaire were used as the instruments of the study. Data were analyzed by analyses of variance with repeated measures. The results showed that both interventions of this study can improve happiness, hope, and quality of life in patients with Parkinson's disease, but Dohsa‐hou is more effective than the Alexander Technique in the improvement of happiness and hope. Probable explanations have been discussed.     

Illness representations,coping and psychological adjustment to Parkinson's disease

The present study reports an application of the common sense model (CSM) of illness representations to the prediction of psychological distress in people with Parkinson's disease (PD). The study sought to (i) examine cross-sectional and prospective associations between illness representations, coping and psychological distress, and (ii) test the hypothesis that coping would mediate any relationships between illness representations and psychological distress. Patients with PD (n = 58) completed the Illness Perception Questionnaire-Revised, the Medical Coping Modes Questionnaire and the Hospital Anxiety and Depression Scale. Patients (n = 57) were followed-up at 6 months. Illness representations explained large amounts of variance in time 1 anxiety (R ² = 0.42) and depression (R ² = 0.44) as well as additional variance in time 2 anxiety (ΔR ² = 0.12) and depression (ΔR ² = 0.09) after controlling for baseline scores. In addition, avoidance mediated the effect of emotional representations on time 1 anxiety, and acceptance-resignation mediated the effects of both consequences and emotional representations on time 1 depression. The present study therefore provides partial support for the mediational model outlined in the CSM, as significant mediation effects were found only in the cross-sectional analyses.     

De l’efficacité d’un « exergame » sur le stress perçu et le sentiment d’auto-efficacité chez un patient atteint de la maladie de Parkinson : résultats d’un protocole à cas unique de type ABAB

IntroductionRehabilitation is of paramount importance in Parkinson's disease because it compensates for deficiencies in the body's structures and functions and preserves relative autonomy for as long as possible. Nevertheless, people with this disease report low adherence to physical activity.ObjectiveThe purpose of this research is to examine the potential psychological benefits of using an “exergame”, a “serious game” based on physical exercise in the functional rehabilitation of Parkinson's disease, including stress and self-efficacy.MethodA single case ABAB protocol (n = 1) over 4 weeks, 1 week per phase, 3 observation points per phase, was developed. Our variables were measured by questionnaires and we used visual and statistical analysis to interpret changes in scores between Phases A and B.OutcomesThe “exergame” intervention appears to improve perceived stress and self-efficacy. The results are accompanied by an exploratory interview, reporting qualitative changes.ConclusionThe use of “exergame” in Parkinson's disease seems promising, and does not harm the person. But the methodology used is not sufficient to conclude on its real effectiveness. Further studies are needed.     

Mental and Motor Switching in Parkinson's Disease

Switching difficulties in Parkinson's disease (PD) are expressed in both mental and motor tasks. The authors of the present study investigated whether those deficits coexist in the same patient and are positively correlated. They tested 8 nondemented PD patients and 6 age-matched control participants by using the modified Wisconsin Card Sorting Test and a motor switching paradigm that is based on the task of reaching toward visual targets, the location of which could unexpectedly be altered within the reaction time. In both mental and motor tasks, patients performed significantly worse than controls. There were no significant correlations between the two types of pathology in individual patients. Mental and motor switching deteriorate in PD patients, but the deficits are not necessarily of parallel severity.

basal ganglia