Prism Adaptation Task Research Articles

Slower rates of prism adaptation but intact aftereffects in patients with early to mid-stage Parkinson's disease

There is currently mixed evidence on the effect of Parkinson's disease on motor adaptation. Some studies report that patients display adaptation comparable to age-matched controls, while others report a complete inability to adapt to novel sensory perturbations. Here, early to mid-stage Parkinson's patients were recruited to perform a prism adaptation task. When compared to controls, patients showed slower rates of initial adaptation but intact aftereffects. These results support the suggestion that patients with early to mid-stage Parkinson's disease display intact adaptation driven by sensory prediction errors, as shown by the intact aftereffect. But impaired facilitation of performance through cognitive strategies informed by task error, as shown by the impaired initial adaptation. These results support recent studies that suggest that patients with Parkinson's disease retain the ability to perform visuomotor adaptation, but display altered use of cognitive strategies to aid performance and generalises these previous findings to the classical prism adaptation task.

Temporal Relationship between Impairment of Cerebellar Motor Learning and Deterioration of Ataxia in Patients with Cerebellar Degeneration.

Ataxia and impaired motor learning are both fundamental features in diseases affecting the cerebellum. However, it remains unclarified whether motor learning is impaired only when ataxia clearly manifests, nor it is known whether the progression of ataxia, the speed of which often varies among patients with the same disease, can be monitored by examining motor learning. We evaluated motor learning and ataxia at intervals of several months in 40 patients with degenerative conditions [i.e., multiple system atrophy (MSA), Machado-Joseph disease (MJD)/spinocerebellar ataxia type 3 (SCA3), SCA6, and SCA31]. Motor learning was quantified as the adaptability index (AI) in the prism adaptation task and ataxia was scored using the Scale for the Assessment and Rating of Ataxia (SARA). We found that AI decreased most markedly in both MSA-C and MSA-P, moderately in MJD, and mildly in SCA6 and SCA31. Overall, the AI decrease occurred more rapidly than the SARA score increase. Interestingly, AIs remained normal in purely parkinsonian MSA-P patients (n = 4), but they dropped into the ataxia range when these patients started to show ataxia. The decrease in AI during follow-up (dAI/dt) was significant in patients with SARA scores < 10.5 compared with patients with SARA scores ≥ 10.5, indicating that AI is particularly useful for diagnosing the earlier phase of cerebellar degeneration. We conclude that AI is a useful marker for progressions of cerebellar diseases, and that evaluating the motor learning of patients can be particularly valuable for detecting cerebellar impairment, which is often masked by parkinsonisms and other signs.

P-MD008. Differential effects of thyrotropin releasing hormone on motor performance and motor adaptation in patients with spinocerebellar degeneration

Introduction . The cerebellum is known to play an important role in motor adaptation, including prism adaptation. Thyrotropin releasing hormone (TRH) has been used as a treatment for cerebellar ataxia in Japan. However, effects of TRH on cerebellar adaptation function have not been studied. Herein, we studied effects of TRH treatment on the prism adaptation task. Methods . Eighteen patients with spinocerebellar degeneration (SCD), including MSA-C, SCA3, SCA6, SCA31, participated in this study. The participants received intravenous injection of 2 mg/day protirelin tartrate once a day for 14 days. In the prism adaptation task, the participants reached to the target on the screen wearing wedge prisms. We compared the Scale for Assessment and Rating of Ataxia (SARA), baseline errors and the after effect (AE) of the prism adaptation task between before and after TRH therapy. We also performed correlation analysis between improvement of baseline errors or AE in the adaptation task, and 1) improvement of the total SARA score, 2) improvement of upper limb ataxia score, and 3) improvement of axial ataxia score. Results . TRH therapy significantly improved SARA (p = 0.005). Multiple regression analysis revealed that improvement of SARA score was mainly due to improvement of “Stance” category score. TRH decreased baseline errors of the prism adaptation task (p = 0.021), while unaffected AEs (p = 0.25). Correlation analysis revealed no significant correlation between any factors. Conclusion . TRH differentially affected cerebellar ataxic symptoms including baseline reaching performance in the prism adaptation task, whereas TRH did not affect the learning process of prism adaptation. Different cerebellar functional aspects may underlie the learning process of motor adaptation and simple motor performance (classical ataxia).

SY1.8. Application of TMS in movement disorders

I will summarize several TMS applications in movement disorders. Function of supplementary motor area (SMA) and preSMA revealed by QPS (Shimzu T et al). We studied functional differences between the pre-SMA and SMA in sequence learning in humans. To induce LTP/LTD, we administered quadripulse transcranial magnetic stimulation (QPS) with an inter-stimulus interval of 5 or 50 ms (QPS-5/50) over the pre-SMA or SMA in healthy volunteers. QPS-5 over the pre-SMA increased the error rate without any changes in movement speed. When administered over the SMA, QPS affected the rate of reaction time reduction across trials without any changes in the error rate. Cerebellar involvement and cerebellar stimulation treatments. Essential tremor (Hanajima et al). Several lines of evidence suggested a cerebellar pathophysiology of essential tremor (ET). It was recently confirmed by human pathology, neuroimaging studies and others. This hypothesis was also confirmed by cerebellar TMS over cerebellum (cerebellar inhibition: CBI) and prism adaptation task in ET patients (Hanajima et al). Cerebellar stimulation treatments in movement disorders (Çan, M et al). Many researchers have been interested in cerebellar involvement in movement disorders and also cerebellar stimulation as one of treatment methods. However, our magnetic coil must activate cerebellum in some extent but not purely cerebellum alone, and always activate some other structures. The simulation study showed considerable amount of currents must be induced in the cerebellum even with a small coil. Cerebellar stimulation is one of future projects of TMS. Transcranial focused ultrasound stimulation (tFUS). Very low intensity tFUS makes reversible functional changes in human brain. This reversible modulation is used for functional studies of human brains. Its focality and ability to induce functional changes in deep brain structures, such as thalamus, must enable this method to be used in movement disorders. Alternative leg movements induction by lumbar rTMS (Nishimura et al). The lumbar gait center is known to produce gait-like alternative leg movements in animals. We made a system to voluntary induce a gait-like leg movement triggered by her/his own upper limb EMGs. This system induced alternative leg movements, gait like movements, in patients with paraplegia due to spinal cord injury.

S4-2 Detection of cerebellar dysfunction by the prism adaptation task

S4-2 Detection of cerebellar dysfunction by the prism adaptation task

Differential effects of thyrotropin releasing hormone (TRH) on motor execution and motor adaptation process in patients with spinocerebellar degeneration

BackgroundThe cerebellum is known to play a crucial role in sensori-motor adaptation, which includes the prism adaptation. TRH has been widely used as a treatment for cerebellar ataxia in Japan, however effects of TRH on cerebellar adaptation process have not been studied. Here, we studied effects of TRH treatment on the prism adaptation task. MethodsEighteen spinocerebellar degeneration (SCD) patients participated in this study. The participants received intravenous injection of 2 mg/day protirelin tartrate once a day for 14 days. In the prism adaptation task, the participants reached to the target on the screen wearing wedge prisms. We compared the Scale for Assessment and Rating of Ataxia (SARA), baseline errors and the aftereffect (AE) of the prism adaptation task between before and after TRH therapy. ResultsTRH therapy improved SARA significantly (p = .005). Multiple regression analysis revealed that improvement of SARA score was mainly due to improvement of “Stance” category score. TRH decreased baseline errors of the prism adaptation task (p = .021), while unaffected AEs (p = .252). ConclusionTRH differentially affected clinical cerebellar ataxia including baseline reaching performance in the prism adaptation task, whereas TRH did not affect the learning process of prism adaptation. Different cerebellar functional aspects may underlie the learning process of sensori-motor adaptation and simple motor execution (clinically evaluated cerebellar ataxia).

Procedural and Strategic Visuomotor Learning Deficits in Children With Developmental Coordination Disorder

ABSTRACT Purpose: Developmental coordination disorder (DCD) is characterized by poor coordination and clumsiness in children. Subjects often show unsteady gait, frequent tripping, and difficulty holding objects. Here we evaluated the implicit and explicit motor learning capabilities of children with DCD. Method: We assessed a total of 80 children (4–12 years old). These children were divided into two groups of 40 participants each. One group with DCD diagnosis and a control group. Using a prism adaptation paradigm, we evaluated whether DCD affects procedural visuomotor adaptation. This adaptation typically occurs during the laterally displacing prism adaptation task. We contrasted these results with the performance during a reversing prism adaptation task, which mainly places demands on strategic visuomotor learning. To solve both adaptation tasks, subjects must perform the same movements, but using two completely different approaches. Results: There was a significant variable error difference between groups, confirming a motor control deficit in individuals with DCD. This group also showed significant visuomotor learning deficits in the displacing task, including less adaptation and smaller aftereffect. The analysis on the reversing task revealed a significant larger number of subjects with DCD that could not adapt, suggesting significant strategic visuomotor learning deficits in this group too. Conclusions: These results demonstrate procedural and strategic visuomotor deficits in this sample of children with DCD.

Impaired Adaptive Motor Learning Is Correlated With Cerebellar Hemispheric Gray Matter Atrophy in Spinocerebellar Ataxia Patients: A Voxel-Based Morphometry Study.

Objective: To evaluate the degree to which recently proposed parameters measured via a prism adaptation task are correlated with changes in cerebellar structure, specifically gray matter volume (GMV), in patients with spinocerebellar degeneration (SCD).Methods: We performed whole-brain voxel-based morphometry (VBM) analysis on 3-dimensional T1-weighted images obtained from 23 patients with SCD [Spinocerebellar ataxia type 6 (SCA6), 31 (SCA31), 3/Machado-Joseph disease (SCA3/MJD), and sporadic cortical cerebellar atrophy (CCA)] and 21 sex- and age-matched healthy controls (HC group). We quantified a composite index representing adaptive motor learning abilities in a hand-reaching task with prism adaptation. After controlling for age, sex, and total intracranial volume, we analyzed group-wise differences in GMV and regional GMV correlations with the adaptive learning index.Results: Compared with the HC group, the SCD group showed reduced adaptive learning abilities and smaller GMV widely in the lobules IV-VIII in the bilateral cerebellar hemispheres. In the SCD group, the adaptive learning index was correlated with cerebellar hemispheric atrophy in the right lobule VI, the left Crus I. Additionally, GMV of the left supramarginal gyrus showed a correlation with the adaptive learning index in the SCD group, while the supramarginal region did not accompany reduction of GMV.Conclusions: This study indicated that a composite index derived from a prism adaptation task was correlated with GMV of the lateral cerebellum and the supramarginal gyrus in patients with SCD. This study should contribute to the development of objective biomarkers for disease severity and progression in SCD.

Effects of TRH therapy on the prism adaptation task in patients with spinocerebellar degeneration

Effects of TRH therapy on the prism adaptation task in patients with spinocerebellar degeneration

1-1-55. Changes of resting-state functional connectivity during prism adaptation in healthy adults: A fMRI study

Prism adaptation (PA) is one of the effective therapies for unilateral spatial neglect (USN), but its mechanism is not well understood. Under the hypothesis that PA is related to functional connectivity (FC) of visual attention network, we investigated the effects of the PA on FC in healthy adults with resting state functional magnetic resonance imaging (rsfMRI). Participants were 5 healthy right-handed volunteers. They wore prism glasses that deviate visual field to the right, and performed reaching task for the target without seeing the trajectory of their own hand. The angle of the prism glasses was gradually increased and the task was repeated 90 times. We estimated brain connectivity with rsfMRI before, immediately after, and one hour after the PA task. With pooled data of all the participants, the FC between left and right middle frontal gyrus decreased significantly immediately after the PA, and returned to baseline in one hour. Leftward deviation as a behavioral after effect seen immediately after the PA seemed to disappear in one hour. These results suggest that the FC in this region is modified by short term visuomotor adaptation. This study suggests that the PA can influence resting-state-functional connectivity between left and right visual attention network.

Cerebellar function and ischemic brain lesions in migraine patients from the general population.

Objective The objective of this article is to obtain detailed quantitative assessment of cerebellar function and structure in unselected migraine patients and controls from the general population. Methods A total of 282 clinically well-defined participants (migraine with aura n = 111; migraine without aura n = 89; non-migraine controls n = 82; age range 43-72; 72% female) from a population-based study were subjected to a range of sensitive and validated cerebellar tests that cover functions of all main parts of the cerebellar cortex, including cerebrocerebellum, spinocerebellum, and vestibulocerebellum. In addition, all participants underwent magnetic resonance imaging (MRI) of the brain to screen for cerebellar lesions. As a positive control, the same cerebellar tests were conducted in 13 patients with familial hemiplegic migraine type 1 (FHM1; age range 19-64; 69% female) all carrying a CACNA1A mutation known to affect cerebellar function. Results MRI revealed cerebellar ischemic lesions in 17/196 (8.5%) migraine patients and 3/79 (4%) controls, which were always located in the posterior lobe except for one control. With regard to the cerebellar tests, there were no differences between migraine patients with aura, migraine patients without aura, and controls for the: (i) Purdue-pegboard test for fine motor skills (assembly scores p = 0.1); (ii) block-design test for visuospatial ability (mean scaled scores p = 0.2); (iii) prism-adaptation task for limb learning (shift scores p = 0.8); (iv) eyeblink-conditioning task for learning-dependent timing (peak-time p = 0.1); and (v) body-sway test for balance capabilities (pitch velocity score under two-legs stance condition p = 0.5). Among migraine patients, those with cerebellar ischaemic lesions performed worse than those without lesions on the assembly scores of the pegboard task ( p < 0.005), but not on the primary outcome measures of the other tasks. Compared with controls and non-hemiplegic migraine patients, FHM1 patients showed substantially more deficits on all primary outcomes, including Purdue-peg assembly ( p < 0.05), block-design scaled score ( p < 0.001), shift in prism-adaptation ( p < 0.001), peak-time of conditioned eyeblink responses ( p < 0.05) and pitch-velocity score during stance-sway test ( p < 0.001). Conclusions Unselected migraine patients from the general population show normal cerebellar functions despite having increased prevalence of ischaemic lesions in the cerebellar posterior lobe. Except for an impaired pegboard test revealing deficits in fine motor skills, these lesions appear to have little functional impact. In contrast, all cerebellar functions were significantly impaired in participants with FHM1.

Modulation of error-sensitivity during a prism adaptation task in people with cerebellar degeneration.

Cerebellar damage can profoundly impair human motor adaptation. For example, if reaching movements are perturbed abruptly, cerebellar damage impairs the ability to learn from the perturbation-induced errors. Interestingly, if the perturbation is imposed gradually over many trials, people with cerebellar damage may exhibit improved adaptation. However, this result is controversial, since the differential effects of gradual vs. abrupt protocols have not been observed in all studies. To examine this question, we recruited patients with pure cerebellar ataxia due to cerebellar cortical atrophy (n = 13) and asked them to reach to a target while viewing the scene through wedge prisms. The prisms were computer controlled, making it possible to impose the full perturbation abruptly in one trial, or build up the perturbation gradually over many trials. To control visual feedback, we employed shutter glasses that removed visual feedback during the reach, allowing us to measure trial-by-trial learning from error (termed error-sensitivity), and trial-by-trial decay of motor memory (termed forgetting). We found that the patients benefited significantly from the gradual protocol, improving their performance with respect to the abrupt protocol by exhibiting smaller errors during the exposure block, and producing larger aftereffects during the postexposure block. Trial-by-trial analysis suggested that this improvement was due to increased error-sensitivity in the gradual protocol. Therefore, cerebellar patients exhibited an improved ability to learn from error if they experienced those errors gradually. This improvement coincided with increased error-sensitivity and was present in both groups of subjects, suggesting that control of error-sensitivity may be spared despite cerebellar damage.

Cerebellar involvement in motor but not sensory adaptation

Predictable sensorimotor perturbations can lead to cerebellum-dependent adaptation—i.e., recalibration of the relationship between sensory input and motor output. Here we asked if the cerebellum is also needed to recalibrate the relationship between two sensory modalities, vision and proprioception. We studied how people with and without cerebellar damage use visual and proprioceptive signals to estimate their hand's position when the sensory estimates disagree. Theoretically, the brain may resolve the discrepancy by recalibrating the relationship between estimates (sensory realignment). Alternatively, the misalignment may be dealt with by relying less on one sensory estimate and more on the other (a weighting strategy). To address this question, we studied subjects with cerebellar damage and healthy controls as they performed a series of tasks. The first was a prism adaptation task that involves motor adaptation to compensate for a visual perturbation and is known to require the cerebellum. As expected, people with cerebellar damage were impaired relative to controls. The same subjects then performed two experiments in which they reached to visual and proprioceptive targets while a visuoproprioceptive misalignment was gradually imposed. Surprisingly, cerebellar patients performed as well as controls when the task invoked only sensory realignment, but were impaired relative to controls when motor adaptation was also possible. Additionally, individuals with cerebellar damage were able to use a weighting strategy similarly to controls. These results demonstrate that, unlike motor adaptation, sensory realignment and weighting are not cerebellum-dependent.

Brain Activity Stimulated by Prism Adaptation Tasks Utilized for the Treatment of Unilateral Spatial Neglect: A Study with fNIRS.

We investigated the neurological basis for efficacy of prism adaptation therapy, which is used for the treatment of poststroke unilateral spatial neglect (USN). Study subjects were 6 USN-positive (+), 6 USN-negative patients, and 6 healthy volunteer control subjects. USN was identified by the Behavioural Inattention Test (BIT). During the tasks, brain activity was assessed with fNIRS via changes in oxyHb concentration per unit length. There was no significant difference in the number of errors in the task between the 3 groups. However, in the USN(+) group there was a significantly greater reduction in oxyHb levels in the right parietal association cortex during the prism adaptation task than in the other 2 groups (P < 0.05). There was an immediate improvement in USN symptoms as well as a significant increase in oxyHb levels during the prism adaptation in the channels covering the right frontal and parietal lobes in 2 patients in the USN(+) group (P < 0.05). This result suggested that decreased activity in the right parietal association cortex, which is related to spatial perception, during the prism adaptation task and task-induced reorganization of the right frontal and parietal areas were involved in improvement in USN symptoms.

Sex-related differences in motor learning and performance

Gender differences have been shown across many domains, and motor skills are no exception. One of the most robust findings is a significant sex difference in throwing accuracy, which reflects the advantage of men in targeting abilities. However, little is known about the basis of this difference. To try to dissect possible mechanisms involved in this difference, here we tested for gender variations in a prism adaptation throwing task. We tested 154 subjects in a visuomotor prism adaptation task that discriminates between motor performance, visuomotor adaptation and negative aftereffects. Our results corroborate men's significant better throwing accuracy, although there were no adaptation differences between genders. In contrast, women showed significant larger negative aftereffects, which could be explained by a larger contribution of spatial alignment. These results suggest that different learning mechanisms, like strategic calibration and spatial alignment, may have different contributions in men and women.

Motor Decline in Clinically Presymptomatic Spinocerebellar Ataxia Type 2 Gene Carriers

BackgroundMotor deficits are a critical component of the clinical characteristics of patients with spinocerebellar ataxia type 2. However, there is no current information on the preclinical manifestation of those motor deficits in presymptomatic gene carriers. To further understand and characterize the onset of the clinical manifestation in this disease, we tested presymptomatic spinocerebellar ataxia type 2 gene carriers, and volunteers, in a task that evaluates their motor performance and their motor learning capabilities.Methods and Findings28 presymptomatic spinocerebellar ataxia type 2 gene carriers and an equal number of control volunteers matched for age and gender participated in the study. Both groups were tested in a prism adaptation task known to be sensible to both motor performance and visuomotor learning deficits. Our results clearly show that although motor learning capabilities are intact, motor performance deficits are present even years before the clinical manifestation of the disease start.ConclusionsThe results show a clear deficit in motor performance that can be detected years before the clinical onset of the disease. This motor performance deficit appears before any motor learning or clinical manifestations of the disease. These observations identify the performance coefficient as an objective and quantitative physiological biomarker that could be useful to assess the efficiency of different therapeutic agents.

Acquisition of internal models of motor tasks in children with autism

Children with autism exhibit a host of motor disorders including poor coordination, poor tool use and delayed learning of complex motor skills like riding a tricycle. Theory suggests that one of the crucial steps in motor learning is the ability to form internal models: to predict the sensory consequences of motor commands and learn from errors to improve performance on the next attempt. The cerebellum appears to be an important site for acquisition of internal models, and indeed the development of the cerebellum is abnormal in autism. Here, we examined autistic children on a range of tasks that required a change in the motor output in response to a change in the environment. We first considered a prism adaptation task in which the visual map of the environment was shifted. The children were asked to throw balls to visual targets with and without the prism goggles. We next considered a reaching task that required moving the handle of a novel tool (a robotic arm). The tool either imposed forces on the hand or displaced the cursor associated with the handle position. In all tasks, the children with autism adapted their motor output by forming a predictive internal model, as exhibited through after-effects. Surprisingly, the rates of acquisition and washout were indistinguishable from normally developing children. Therefore, the mechanisms of acquisition and adaptation of internal models in self-generated movements appeared normal in autism. Sparing of adaptation suggests that alternative mechanisms contribute to impaired motor skill development in autism. Furthermore, the findings may have therapeutic implications, highlighting a reliable mechanism by which children with autism can most effectively alter their behaviour.

Posterior parietal cortex and the dissociable components of prism adaptation

Recent evidence has implicated posterior parietal cortex (PPC) in adaptation to optical displacing prisms. It has been suggested that PPC contributes to the strategic component of prism adaptation necessary for perceptual realignment (true adaptation). It has also been suggested, however, that the part of PPC responsible for corrections to ongoing movements (a putative strategic component) may not be necessary for successful adaptation. A patient presenting with bilateral posterior parietal damage (patient JJ) was tested with both hands on two versions of a prism adaptation task—one using prism goggles and one using a virtual prism arrangement. JJ displayed independent deficits: his right hand failed to show strategic control, yet adapted fully to the prisms whereas his left hand showed evidence of strategic control without subsequent adaptation. The data indicates that the ability to implement control strategies may not be necessary for successful adaptation to prisms. A proposed model for the role of posterior parietal cortex in prism adaptation is also presented.

Role of posterior parietal cortex in the recalibration of visually guided reaching.

Visually guided reaching requires complex neural transformations to link visual and proprioceptive inputs with appropriate motor outputs. Despite the complexity of these transformations, hand-eye coordination in humans is remarkably flexible, as demonstrated by the ease with which reaching can be adapted to distortions in visual feedback. If subjects attempt to reach to visual targets while wearing displacing prisms, they initially misreach in the direction of visual displacement. Given feedback about their reaching errors, however, they quickly adapt to the visual distortion. This is shown by the gradual resumption of accurate reaching while the prisms remain in place, and by the immediate onset of reaching errors in the opposite direction after the prisms have been removed. Despite an abundance of psychophysical data on adaptation to prisms, the functional localization of this form of sensorimotor adaptation is uncertain. Here we use positron emission tomography (PET) to localize changes in regional cerebral blood flow (rCBF) in subjects who performed a prism-adaptation task as well as a task that controlled for the sensory, motor and cognitive conditions of the adaptation experiment. Difference images that reflected the net effects of the adaptation process showed selective activation of posterior parietal cortex contralateral to the reaching limb.

Prism adaptation and other tasks involving spatial abilities in patients with Parkinson's disease, patients with frontal lobe lesions and patients with unilateral temporal lobectomies

Patients in the early stages of Parkinson's disease were compared with patients who had sustained damage specific to either the frontal or temporal lobes and normal controls on a delayed alternation task, a test of the left-right orientation and a prism adaptation task. On the former two tasks age accounted for more of the variability in performance than did site of brain lesion. However, patients with frontal lobe, right temporal lobe or basal ganglia damage were significantly impaired on the adaptation task. The results are discussed with regard to “switching”, “sequencing” and “internal guidance” of movement hypotheses.