Matching accuracy in hemiparetic cerebral palsy during unimanual and bimanual movements with (mirror) visual feedback

In the present study participants with Spastic Hemiparetic Cerebral Palsy (SHCP) were asked to match the position of a target either with the impaired arm only (unimanual condition) or with both arms at the same time (bimanual condition). The target was placed at 4 different locations scaled to the individual maximum reaching distance. To test the effect of mirror visual feedback of the less-impaired arm on the matching accuracy, an opaque screen or a mirror was placed in between the arms which masked vision of the impaired arm. Absolute endpoint error was smaller in the bimanual condition compared to the unimanual condition, but there was no effect of mirror visual feedback. Inspection of the individual data, however, showed that 13 out of 23 participants did experience a positive effect of mirror visual feedback. A positive correlation between the baseline error (screen) and the improvement in accuracy with mirror visual feedback seems to suggest that individuals with lower proprioceptive accuracy in the baseline condition may benefit more from mirror visual feedback. Together these findings indicate that bimanual therapy and therapy with mirror visual feedback might be valuable approaches for rehabilitation for a subset of the individuals with SHCP.     

Deficits in upper limb position sense of children with Spastic Hemiparetic Cerebral Palsy are distance-dependent

This study examined the arm position sense in children with Spastic Hemiparetic Cerebral Palsy (SHCP) and typically developing children (TD) by means of a contralateral matching task. This task required participants to match the position of one arm with the position of the other arm for different target distances and from different starting positions. Results showed that children with SHCP exhibited with both arms larger matching errors than the TD group, but only when the distance between the arms at the start of the movement was large. In addition, the difference in errors between the less-impaired and the impaired limb changed as a function of the distance in the SHCP group whereas no interlimb differences were found in the TD group. Finally, spasticity and restricted range of motion in children with SHCP were not related to the proportion of undershoot and size of absolute error. This suggests that SHCP could be associated with sensory problems in conjunction with their motor problems. In conclusion, the current study showed that accurate matching of the arms is greatly impaired in SHCP when compared to TD children, irrespective of which arm is used. Moreover, this deficit is particularly present for large movement amplitudes.     

Mirror visual feedback induces lower neuromuscular activity in children with spastic hemiparetic cerebral palsy

The study examined the effects of mirror feedback information on neuromuscular activation during bimanual coordination in eight children with spastic hemiparetic cerebral palsy (SHCP) and a matched control group. The ‘mirror box’ creates a visual illusion, which gives rise to a visual perception of a zero lag, symmetric movement between the two arms. The study incorporated two additional visual feedback conditions by placing a glass or opaque screen between the arms. During bilateral symmetric circular arm movements mirror visual feedback induced lower neuromuscular intensities in the shoulder muscles of the less impaired arm of children with SHCP compared to the other visual conditions. In addition, the mirror lead to shorter relative durations of eccentric and concentric activity in the elbow muscles of the more impaired arm, whereas no effects of visual feedback were found in a matched control group. These results suggest that replacing veridical visual information of the more impaired arm with a mirror reflection of the less impaired arm improves the motor control of children with SHCP during interlimb coupling. The effects of the availability of visual feedback in individuals with hemiparesis are discussed with reference to: (1) increase ipsilateral motor cortex excitability and (2) congruence between afferent (visual) feedback and the internal copy of the motor commands.     

Practicing a matching movement with a mirror in individuals with spastic hemiplegia

This experimental study aimed to determine the effect of practicing a position matching task with (mirror) visual feedback of the less-impaired arm on the matching accuracy of the impaired arm in children and adolescents with spastic hemiparetic cerebral palsy. Practice consisted of 40 trials of bimanual target matching, where one group received regular visual feedback and a second group received mirror visual feedback of the less-impaired arm. On three occasions (pre, post, and after a 1-week-retention) position sense (matching accuracy measured as the endpoint error in cm) of the impaired arm was tested with a unimanual and bimanual matching task, performed without any visual information of either hand. Matching accuracy of the impaired arm was better in the post-test than in the pre-test, but this improvement was similar for both practice groups. In the retention-test, accuracy had returned to pre-test-level, which might be ascribed to the short duration of the practice period. These outcomes suggest that practicing a matching task with visual feedback of the less-impaired arm might help to improve the matching accuracy of the impaired arm in individuals with spastic hemiparetic cerebral palsy.     

Neural correlates of proprioceptive upper limb position matching

Proprioceptive information allows humans to perform smooth coordinated movements by constantly updating one's mind with knowledge of the position of one's limbs in space. How this information is combined with other sensory modalities and centrally processed to form conscious perceptions of limb position remains relatively unknown. What has proven even more elusive is pinpointing the contribution of proprioception in cortical activity related to motion. This study addresses these gaps by examining electrocortical dynamics while participants performed an upper limb position matching task in two conditions, namely with proprioceptive feedback or with both visual and proprioceptive feedback. Specifically, we evaluated the reduction of the electroencephalographic power (desynchronization) in the μ frequency band (8–12 Hz), which is known to characterize the neural activation associated with motor control and behavior. We observed a stronger desynchronization in the left motor and somatosensory areas, contralateral to the moving limb while, parietal and occipital regions, identifying association and visual areas, respectively, exhibited a similar activation level in the two hemispheres. Pertaining to the influence of the two experimental conditions it affected only movement's offset, and precisely we found that when matching movements are performed relying only on proprioceptive information, a lower cortical activity is entailed. This effect was strongest in the visual and association areas, while there was a minor effect in the hand motor and somatosensory areas.     

Alien limb following posterior cerebral artery stroke: Failure to recognize internally generated movements?

We describe two rare cases of alien limb syndrome following right posterior cerebral artery (PCA) stroke. Both patients present with left hemianopia, visual neglect and proprioceptive loss in addition to their alien limb symptoms. Lesion subtraction from seven control PCA patients revealed that medial parietal-occipital and thalamic areas were selectively damaged in the alien limb patients. We propose that loss of the sense of motor intention and internal model of the current state of the arm, combined with deficient proprioceptive and visual feedback of the moving limb, are critical for genesis of posterior alien limb and discuss how affected regions normally function to ensure awareness of self-generated motor activity.     

Low-dose/high-concentration localized botulinum toxin A improves upper limb movement and function in children with hemiplegic cerebral palsy

The objective was to determine the effects of low-dose, high-concentration, dual localized botulinum toxin A (BTX-A) injections on upper limb movement quality and function. Study design was an evaluator-blinded, randomized, controlled trial. Forty-two children (31 males, 11 females; range 2-8y, mean 4y [SD 1.6]) with hemiplegic cerebral palsy (Gross Motor Function Classification System level I) participated. All received occupational therapy. The treatment group (n=21) received one injection series (mean muscles injected 6 [SD 1.05]; total dose 82-220 units, mean 139 [SD 37.48]; dilution 100 units/0.5ml). Primary outcome of Quality of Upper Extremity Skills Test (QUEST) at 6 months was not significant (p=0.318). Secondary outcomes were average treatment effects at 1, 3, and 6 months, which favoured the treatment group: QUEST (p<0.001); Canadian Occupational Performance Measure (performance, p=0.002; satisfaction p=0.007); parent Goal Attainment Scaling (GAS; p=0.001), therapist GAS (p<0.001); Pediatric Evaluation of Disability Inventory (PEDI) functional skills (p=0.030); Ashworth (p<0.001). PEDI caregiver assistance was not significant (p=0.140). Therapy alone is effective, but at 1 and 3 months movement quality is better where BTX-A is also used. Moreover, function is better at 1, 3, and 6 months, suggesting BTX-A enhances therapy outcomes beyond the pharmacological effect. One- and 3-month Ashworth and QUEST scores suggest precise needle placement accuracy.     

Adverse effects of motor-related symptoms on the ipsilateral upper limb according to long-term cane usage

Objective: Although the cane is prescribed to aid in daily living and social participation in stroke patients, this study aimed to identify whether long-term cane usage affected sensorimotor functions in the distal part of the non-affected upper limb in relation to a tracking task, a nine-hole pegboard test, and proprioceptive joint sense. Patient and method: Forty stroke patients who were divided into a cane using group (CUG) or a non-cane using group (NCUG) participated in this study. Subjects were evaluated in a tracking task for visuomotor coordination, a nine-hole pegboard test for dexterous hand motion, and a joint reposition test for proprioceptive sense integrity. Result: Comparison of the CUG and NCUG revealed significant differences in performance of the tracking task, the nine-hole pegboard test, and the joint reposition test (p < 0.05). The CUG had more difficulty performing visuomotor coordination and dexterous hand motion tasks compared with the NCUG. Proprioceptive joint sense was also deteriorated in the CUG.Conclusion: These results suggest that stroke patients who use a cane for a long period, could experience decreased sensorimotor function in the ipsilateral upper limb of a damaged hemisphere. Therefore, it will be necessary to provide careful evaluation and appropriate therapeutic intervention for stroke patients who require the use of a cane over a long period.     

Kinematic analysis of upper limb trajectories in Parkinson's disease.

The purpose of this study was to analyze the kinematic properties of upper limb trajectories in Parkinson's disease (PD) patients and to investigate the role of visual feedback from the moving limb. Beyond the characteristic bradykinesia, PD patients differed from controls by generating hand trajectories with asymmetrical velocity profiles that lacked smoothness and were composed of a short initial accelerative phase, followed by a prolonged interval composed of alternating decelerative and accelerative phases. In both groups, the reaction times for movements directed away from the body were longer than for movements directed toward the body; this effect was accentuated in PD. In both groups, initial peak accelerations were significantly larger for distally as compared to proximally directed movements. In the absence of visual feedback from the limb a deterioration in the accuracy of reaching the target was observed in both control and PD patients only for distally directed movements. However, this deterioration and the effect of target location on final accuracy was substantially larger in PD. Taken together, our study suggests that in PD visual information is continuously relied upon for ongoing movement correction, therefore accentuating the bradykinesia. The deficit in final accuracy in the absence of visual feedback reflects the important role played by the basal ganglia in sensorimotor integration.     

Partitioning the components of visuomotor adaptation to prism-altered distance

While the mechanisms of short-term adaptation to prism-altered apparent visual direction have been widely investigated, the processes underlying adaptation to prism-altered perceived distance are less well known. This study used a hand-pointing paradigm and exposure with base-out prisms to evaluate the relative contributions of sensory (visual and proprioceptive) and motor components of adaptation to perceived-distance alteration. A main experiment was designed to elicit adaptation at the sensory and motor levels, by giving subjects altered visual feedback. A control experiment without visual feedback allowed the effects of eye muscle potentiation (EMP) induced by sustained fixation through the prisms to be uncovered. In the main experiment, the aftereffects were partitioned into two-thirds visual and one-third motor, with no significant proprioceptive component. These results differ from the classical pattern of short-term adaptation to prism-altered apparent visual direction, which includes mainly proprioceptive/motor adaptive components, with a smaller visual component. This difference can be attributed to differences in accuracy between proprioception and vision for localization in depth or in lateral directions. In addition, a comparison of the visual aftereffects in the main and control experiments revealed two sub-components with equal contributions: a recalibration of the mapping between the vergence signal and perceived distance, and an EMP-related aftereffect. These findings indicate that “visual” adaptation actually involves a multiplicity of processes.     

Metal bar prevents phantom limb motion: Case study of an amputation patient who showed a profound change in the awareness of his phantom limb

This case report describes an amputee (patient A.S., a 60-year-old male forelimb amputee) who had an extraordinary experience with a phantom limb. He complained that he could not move the wrist of his phantom limb because a metal bar was perceived to be grasped by the hand. As a solution for removing the metal bar, we invited the patient to undergo mirror reflection-induced visual feedback therapy. The patient reported that the metal bar previously grasped by his hand was successfully removed from the phantom during the course of therapy. Interestingly, this experience was accompanied by profound changes in the EMG modulation in the residual wrist muscles. In this article, the possible mechanisms underlying this interesting phenomenon will be discussed.     

Visual–proprioceptive mapping in children with developmental coordination disorder

Developmental coordination disorder (DCD) occurs in a small but significant proportion of children who present with impaired body-eye coordination and show poor acquisition of motor skills. This study investigated the visual-proprioceptive mapping ability of children with DCD from a small selected group, with particular reference to the use of vision in matching tasks. The children with DCD in this study were significantly poorer than control children on all matching tasks. They seemed to have particular difficulty in cross-modal judgements that required the use of visual information to guide proprioceptive judgements of limb position. A distinction is drawn between tasks that can be achieved purely through sensory matching and those that require body-centred spatial judgements, suggesting that it is the latter that posits a particular difficulty for children with DCD.     

Kinematic properties of upper limb trajectories in idiopathic torsion dystonia.

The kinematic properties of upper limb trajectories of simple reaching movements have been analysed in patients with idiopathic torsion dystonia (ITD). The velocity profiles differed from those of neurologically healthy subjects by being less symmetric. In several patients movement execution was slow due to a longer deceleration time. This phenomenon was even more conspicuous in the absence of visual feedback from the limb and was accompanied by a significant decrease in the final accuracy. These findings show that patients with ITD have deficits in central motor mechanisms beyond abnormal muscle activation patterns. Similarities between kinematic properties of patients with ITD and patients with Parkinson's disease including the deterioration of motor performance in ITD in the absence of visual feedback from the limb, suggest the existence of abnormalities in sensorimotor integration in both diseases.     

Cerebellar dyssynergia in humans—A quantitative analysis

Patients with cerebellar lesions and limb ataxia performed two types of continuous tracking tasks involving flexion and extension of the index finger. In both tasks, patients were provided cutaneous and proprioceptive cues, but visual feedback was given in the first task (visual tracking) and not in the second (arbitrarily termed proprioceptive tracking). Raw records and Fourier-analyzed power spectra were compared with results in normal controls. Harmonic distortion was determined for each task. In all patients, as well as normal subjects, tracking performance was markedly improved and harmonic distortion substantially reduced during proprioceptive tracking. This surprising finding may result from a much shorter feedback loop for proprioceptive stimuli compared to visual stimuli. The tracking records, power spectra analysis, and determination of harmonic distortion provide both qualitative and quantitative data in patients with dyssynergia.     

Imitation of facial expressions in schizophrenia

Diminished facial expressivity is a common feature of schizophrenia that interferes with effective interpersonal communication. This study was designed to determine if real-time visual feedback improved the ability of patients with schizophrenia to imitate and produce modeled facial expressions. Twenty patients with schizophrenia and 10 controls viewed static images of facial expressions and were asked to imitate them. Half of the images were imitated with the use of a mirror and half were imitated without the use of a mirror. In addition, we examined whether practice in imitating and producing expressions improved the ability of participants to generate facial expressions on their own, without the aid of a model or mirror. Participants' facial expressions were photographed with a digital camera and each was rated for accuracy in producing characteristic facial expressions. Patients with schizophrenia were less accurate in imitating and producing facial expressions than controls, and real-time visual feedback did not improve accuracy in either group. Preliminary findings suggest that exposure to model expressions and practice in generating these expressions can improve the accuracy of certain posed expressions in schizophrenia.     

Further evidence of validity of the Modified Melbourne Assessment for neurologically impaired children aged 2 to 4 years

Aim This paper reports the second phase of a study to extend the Melbourne Assessment for use with children with neurological impairment aged 2 to 4 years. The aim was to establish if (1) children’s scores on the Modified Melbourne Assessment (MMA) and the Quality of Upper Extremity Skills Test (QUEST) showed a moderate to high, positive relation, (2) children had comparable behaviours for task and time demands on both tools, and (3) scores on the MMA could discriminate between children with mild, moderate, and severe levels of upper limb impairment. Method An observational study of 30 children (19 males, 11 females) with neurological impairment aged 2 to 4 years. Twenty‐four children had spasticity (20 with a unilateral and four with a bilateral impairment) and two children presented with athetosis, two with ataxia, and two with hypotonia. Results A high, positive relation was found between children’s scores on the MMA and the QUEST (ρ=0.90; p=0.001). The clinical use of the MMA was comparable to the QUEST. MMA scores were able to discriminate between children’s levels of upper limb impairment as determined by clinicians’ ratings (F_2,27=67.76, p=0.001). Interpretation These findings suggest the MMA can be clinically useful for children as young as 2.5 years and has the advantage of being valid for use with older children. Scores from the tool can also provide therapists with a quantitative means of consistently reporting level of upper limb impairment.     

Brief Report: Visuo-spatial Guidance of Movement during Gesture Imitation and Mirror Drawing in Children with Autism Spectrum Disorders

Thirteen autistic and 14 typically developing children (controls) imitated hand/arm gestures and performed mirror drawing; both tasks assessed ability to reorganize the relationship between spatial goals and the motor commands needed to acquire them. During imitation, children with autism were less accurate than controls in replicating hand shape, hand orientation, and number of constituent limb movements. During shape tracing, children with autism performed accurately with direct visual feedback, but when viewing their hand in a mirror, some children with autism generated fewer errors than controls whereas others performed much worse. Large mirror drawing errors correlated with hand orientation and hand shape errors in imitation, suggesting that visuospatial information processing deficits may contribute importantly to functional motor coordination deficits in autism.     

Upper limb activity measures for 5- to 16-year-old children with congenital hemiplegia: a systematic review

Aim  This systematic review aimed to compare the validity, reliability, evaluative validity, and clinical utility of upper limb activity measures for children aged 5 to 16 years with congenital hemiplegia.
Method  Electronic databases were searched to identify assessments that measure upper limb activity available for use and for which published validity and reliability data for the population are obtainable. Assessment items were coded according to the International Classification of Functioning, Disability and Health (ICF) categories to determine if at least 35% of the assessment items fell within the activity component of the ICF. Assessments that met these criteria were included in the review.
Results  Thirty-eight measures were identified, and five met the inclusion criteria. The best measure of unimanual capacity was the Melbourne Assessment of Unilateral Upper Limb Function (MUUL); however, the Shriners Hospital Upper Extremity Evaluation (SHUEE) and the Quality of Upper Extremity Skills Test (QUEST) could also be considered, depending on the type of information required. The performance-based measure of bimanual upper limb activity in children with hemiplegia with the best psychometric properties was the Assisting Hand Assessment (AHA). The ABILHAND-Kids is a parent-report, performance-based questionnaire with excellent clinical utility and psychometric properties.
Interpretation  Clinicians may choose to use more than one of these measures to detect changes in unimanual or bimanual upper limb activity.     

Proprioceptive sensibility in the elderly: degeneration, functional consequences and plastic-adaptive processes

As the percentage of individuals over the age of 60 years continues to rise, determining the extent and functional significance of age-related declines in sensorimotor performance is of increasing importance. This review examines the specific contribution of proprioceptive feedback to sensorimotor performance in older adults. First, a global perspective of proprioceptive acuity is provided assimilating information from studies where only one of several aspects of proprioceptive function (e.g. sense of position, motion or dynamic position) was quantified, and/or a single joint or limb segment tested. Second, the consequences of proprioceptive deficits are established with particular emphasis placed on postural control. Lastly, the potential for plastic changes in the aging proprioceptive system is highlighted, including studies which relate physical activity to enhanced proprioceptive abilities in older adults. Overall, this review provides a foundation for future studies regarding the proprioceptive feedback abilities of elderly individuals. Such studies may lead to greater advances in the treatment and prevention of the sensorimotor deficits typically associated with the aging process.     

镜像疗法结合循经按摩对脑梗死偏瘫患者上肢功能的疗效观察

目的观察镜像疗法结合循经按摩对脑梗死偏瘫患者上肢运动功能及日常生活活动能力的影响。方法将贵州中医药大学第二附属医院神经内科病房的60例脑梗死偏瘫患者随机分为镜像组、循经按摩组、结合组,每组20例。3组均采取常规治疗及康复,在此基础上,镜像组采用镜像视觉反馈康复训练,循经按摩组采用循上肢手阳明大肠经按摩,结合组在镜像视觉反馈的基础上结合循经按摩。于干预前及干预3周后,比较各组患者患侧上肢Fugl-Meyer运动功能(FMA)、改良Ashworth痉挛评定、改良Barthel指数(MBI)评分。结果3组患者干预前患侧上肢FMA、MBI评分及Ashworth痉挛评定比较,差异均无统计学意义(P>0.05);干预3周后,3组患者患侧上肢FMA、MBI评分均较干预前提高,差异有统计学意义(P<0.05);干预后结合组患侧上肢FMA、MBI得分较镜像组和循经按摩组更优(P<0.05);干预后镜像组Ashworth痉挛评定结果无明显差异(P>0.05),循经按摩组及结合组Ashworth痉挛评定级别均降低,差异有统计学意义(P<0.05);相比镜像组,干预后结合组Ashworth痉挛评定差异有统计学意义(P<0.05)。结论镜像疗法结合循经按摩可以有效降低脑梗死偏瘫患者肌张力,改善患侧上肢运动功能,提高日常生活活动能力,治疗效果优于单独使用镜像疗法和单独使用循经按摩。