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

Lower extremity proprioception and its association with activity and participation in children with unilateral spastic cerebral palsy

OBJECTIVE

This cross-sectional study aimed to assess lower extremity proprioception and investigate its relationship to activity and participation levels in children with unilateral spastic cerebral palsy (USCP).

METHODS

A total of 22 children with USCP between the ages of 5 and 16 years participated in this study. Lower extremity proprioception was evaluated with a protocol that consisted of verbal and location identification, unilateral and contralateral limb matching, and static and dynamic balance tests performed with the impaired and less impaired lower extremities under eyes-open and eyes-closed conditions. Furthermore, the Functional Independence Measure (WeeFIM) and Pediatric Outcomes Data Collection Instrument (PODCI) were used to evaluate the independence levels in daily living activities and participation levels.

RESULTS

Children demonstrated proprioceptive loss, as evidenced by an increase in matching errors under the eyes-closed condition compared to the eyes-open condition (p<0.05). Also, the impaired extremity had greater proprioceptive loss than the less impaired extremity (p<0.05). The 5-6-year age group experienced greater proprioceptive deficits than did the 7-11 and 12-16 age groups (p<0.05). Children's lower extremity proprioceptive deficit was moderately associated with their activity and participation levels (p<0.05).

CONCLUSIONS

Our findings suggest that treatment programs based on comprehensive assessments, including proprioception, may be more effective in these children.

Construct validity, reliability, and responsiveness of the Wrist Position Sense Test for use in children with hemiplegic cerebral palsy

INTRODUCTION

We investigate the construct validity, test re-test reliability, and responsiveness of the Wrist Position Sense Test (WPST) for children with hemiplegic cerebral palsy (CP).

METHODS

Twenty-eight children with spastic hemiplegic CP [mean age 10.8 years; SD 2.4 years] and 39 typically developing (TD) children [mean age 11 years; SD 2.9 years] participated in a cross-sectional study to investigate construct validity and association with an upper limb activity measure, the Box and Block Test (BBT). Twenty-two TD children were tested at a second time-point to examine reliability. Test responsiveness was determined by random allocation of 17 children with CP to a treatment (n = 10) or control (n = 7) group with assessments completed at four time-points.

RESULTS

Significantly greater differences were observed in mean error of indicated wrist position (p < 0.01) in children with CP at baseline (M = 21.6°, SD = 21.6°) than in TD children (M = 12.8°, SD = 11.0°). Larger WPST errors were associated with poorer performance on the BBT (p < 0.01) indicating a substantial association, and there were no consistent differences between time-points indicating test re-test reliability within a TD population. The WPST demonstrated responsiveness to intervention with a statistically significant reduction in mean error following treatment (p < 0.001), not seen in the control group (p = 0.28).

CONCLUSION

The WPST demonstrated construct validity in this preliminary study. Scores were associated with an upper limb activity measure, and scores changed significantly following somatosensory training. These findings support further research and future psychometric investigation of the WPST in children with CP.

KEY POINTS FOR OCCUPATIONAL THERAPY

This study provides psychometric knowledge about the WPST tool The WPST shows promise as a discriminative measure with preliminary evidence of responsiveness and intra-rater reliability Until further testing, the WPST can be used cautiously in future research studies to measure wrist position sense.

Somatosensory deficits and neural correlates in cerebral palsy: a scoping review

AIM

To synthetize studies assessing somatosensory deficits and alterations in cerebral responses evoked by somatosensory stimulation in individuals with cerebral palsy (CP) compared to typically developing individuals.

METHOD

A scoping review of the literature was performed in the MEDLINE, Embase, PsycInfo, CINAHL, Evidence-Based Medicine Reviews, and Web of Science databases (last search carried out on 6th and 7th August 2020) with a combination of keywords related to CP and somatosensory functions. Somatosensory deficits were measured with clinical tests and alterations in cerebral responses were measured with functional magnetic resonance imaging, electroencephalography, and magnetoencephalography.

RESULTS

Forty-eight articles were included. Overall, 1463 participants with CP (mean [SD] age 13y 1mo [4y 11mo], range 1-55y; 416 males, 319 females, sex not identified for the remaining participants) and 1478 controls (mean [SD] age 13y 1mo [5y 8mo], range 1-42y; 362 males, 334 females, sex not identified for the remaining participants) were included in the scoping review. For tactile function, most studies reported registration (8 out of 13) or perception (21 out of 21) deficits in participants with CP. For proprioception, most studies also reported registration (6 out of 8) or perception (10 out of 15) deficits. Pain function has not been studied as much, but most studies reported registration (2 out of 3) or perception (3 out of 3) alterations. Neuroimaging findings (18 studies) showed alterations in the somatotopy, morphology, latency, or amplitude of cortical responses evoked by somatosensory stimuli.

INTERPRETATION

Despite the heterogeneity in the methods employed, most studies reported somatosensory deficits. The focus has been mainly on tactile and proprioceptive function, whereas pain has received little attention. Future research should rigorously define the methods employed and include a sample that is more representative of the population with CP. What this paper adds Most of the papers reviewed found tactile registration and perception deficits in the upper limbs. Proprioceptive deficits were generally observed in cerebral palsy but results were heterogeneous. Pain has received little attention compared to tactile and proprioceptive functions. Neuroimaging studies supported behavioral observations. Alterations were observed for both the most and least affected limb.

Active Joint Position Sense in Children With Unilateral Cerebral Palsy

Objective

The aim of the study was to examine the differences in joint position sense at the elbow joint between 15 children with unilateral cerebral palsy (CP) and 15 typically developing (TD) controls without neurological or other health deficits.

Methodology

Joint position sense, a major proprioceptive component, was evaluated actively using a Kin Com 125 AP isokinetic dynamometer (Chattanooga Group, Chattanooga, TN).

Results

A significant interaction was found (p<0.05) between disability and side, with respect to the active reproduction movement scores. Post-hoc independent t-tests, with Bonferroni adjustments, revealed significant differences for the dominant (t=-3.63, p=0.001) and non-dominant sides respectively (t=-6.19, p=0.000). Repeated measures t-test revealed wider errors with the non-dominant (affected side) in the active reproduction test, compared to the dominant (nonaffected) side for the CP group of children (t=-4.73, p=0.000). A positive correlation was evident between the level of spasticity and joint position sense (Rho=0.71, p=0.003).

Conclusions

Based on our findings, joint position sense is impaired at the elbow joint in children with spastic hemiplegia. The proprioceptive deficit is present at both the affected and unaffected sides and is related to the level of spasticity.

Assessment of bilateral motor skills and visuospatial attention in children with perinatal stroke using a robotic object hitting task

Background

While motor deficits are the hallmark of hemiparetic cerebral palsy, children may also experience impairments in visuospatial attention that interfere with participation in complex activities, including sports or driving. In this study, we used a robotic object hitting task to assess bilateral sensorimotor control and visuospatial skills in children with hemiparesis due to perinatal arterial ischemic stroke (AIS) or periventricular venous infarct (PVI). We hypothesized that performance would be impaired bilaterally and be related to motor behavior and clinical assessment of visuospatial attention.

Methods

Forty-nine children with perinatal stroke and hemiparetic cerebral palsy and 155 typically developing (TD) children participated in the study. Participants performed a bilateral object hitting task using the KINARM Exoskeleton Robot, in which they used virtual paddles at their fingertips to hit balls that fell from the top of the screen with increasing speed and frequency over 2.3 min. We quantified performance across 13 parameters including number of balls hit with each hand, movement speed and area, biases between hands, and spatial biases. We determined normative ranges of performance accounting for age by fitting 95% prediction bands to the TD children. We compared parameters between TD, AIS, and PVI groups using ANCOVAs accounting for age effects. Lastly, we performed regression analysis between robotic and clinical measures.

Results

The majority of children with perinatal stroke hit fewer balls with their affected arm compared to their typically developing peers. We also found deficits with the ipsilesional (“unaffected”) arm. Children with AIS had greater impairments than PVI. Despite hitting fewer balls, we only identified 18% of children as impaired in hand speed or movement area. Performance on the Behavioral Inattention Test accounted for 21–32% of the variance in number of balls hit with the unaffected hand.

Conclusions

Children with perinatal stroke-induced hemiparetic cerebral palsy may have complex bilateral deficits reflecting a combination of impairments in motor skill and visuospatial attention. Clinical assessments and interventions should address the interplay between motor and visuospatial skills.

New functions for the proprioceptive system in skeletal biology

Muscle spindles and Golgi tendon organs (GTOs) are two types of sensory receptors that respond to changes in length or tension of skeletal muscles. These mechanosensors have long been known to participate in both proprioception and stretch reflex. Here, we present recent findings implicating these organs in maintenance of spine alignment as well as in realignment of fractured bones. These discoveries have been made in several mouse lines lacking functional mechanosensors in part or completely. In both studies, the absence of functional spindles and GTOs produced a more severe phenotype than that of spindles alone. Interestingly, the spinal curve phenotype, which appeared during peripubertal development, bears resemblance to the human condition adolescent idiopathic scoliosis. This similarity may contribute to the study of the disease by offering both an animal model and a clue as to its aetiology. Moreover, it raises the possibility that impaired proprioceptive signalling may be involved in the aetiology of other conditions. Overall, these new findings expand considerably the scope of involvement of proprioception in musculoskeletal development and function.This article is part of the Theo Murphy meeting issue 'Mechanics of development'.

Using Feedback Control to Reduce Limb Impedance during Forceful Contractions

Little is known about the ability to precisely regulate forces or torques during unexpected disturbances, as required during numerous tasks. Effective force regulation implies small changes in force responding to externally imposed displacements, a behavior characterized by low limb impedance. This task can be challenging, since the intrinsic impedance of muscles increases when generating volitional forces. The purpose of this study was to examine the ability to voluntarily reduce limb impedance during force regulation, and the neural mechanisms associated with that ability. Small displacement perturbations were used to quantify elbow impedance during the exertion of volitional elbow torques from 0% to 20% of maximum voluntary contraction. Subjects were instructed either to not intervene with the imposed perturbations or to explicitly intervene so as to minimize the influence of the perturbations on the elbow torque. Our results demonstrated that individuals can reduce the low frequency components of elbow impedance by 35%. Electromyographic analysis suggested that this behavior is mediated by volitional and possibly long-latency reflex pathways with delays of at least 120 ms. These results provide a context for understanding how feedback altered by aging or injuries may influence the ability to regulate forces precisely.

Postural adaptation during arm raising in children with and without unilateral cerebral palsy

Postural sway during arm movements were related to the size of the base of support (BOS) and the limits of stability (LOS) of children with unilateral cerebral palsy (USCP) and typically developing (TD) children. For half of the trials the mechanical disturbance due to the rapid arm movement was increased by attaching small weights at the wrists. The participants stood with both feet on a large force plate, which recorded the displacements of the center of pressure (CoP). The results showed that in the children with USCP the LOS forward and toward the non-dominant (more-affected) side were smaller than in the TD children whereas the LOS backward and toward the dominant (less-affected) side did not differ between the two groups. When rapidly moving the arms the children with USCP swayed over a larger portion of their base of support in the forward direction and toward their more-affected side. In addition, the maximal sway toward the more-affected side during arm movement exceeded the LOS while balance was maintained. These effects increased when the movements were performed with the weights at the wrists. These results show that an area of permissible sway, which was not spontaneously explored during the leaning task, was required to maintain balance during the supra-postural task. Training to enlarge the LOS that includes weight shifts toward the more-affected side might reduce the area of the BOS that is self-perceived as less secure.

Motor learning in children with hemiplegic cerebral palsy and the role of sensation in short-term motor training of goal-directed reaching

AIM

Our aim was to determine if improved upper limb kinematics in children with cerebral palsy (CP) during a reach-to-grasp task could be retained and transferred to a similar task. We also characterized the relationship between sensation and motor learning.

METHOD

We used a prospective, single-participant research design with 16 children (seven males, nine females; mean/median age 8.6/9 y; age range 6-11 y) with spastic hemiparesis (Manual Ability Classification System levels II-IV). Children were randomly allocated to one of two groups: (1) task-oriented training with or (2) without trunk restraint. The intervention consisted of three 1-hour sessions per week for 5 weeks (total 15 h). Evaluations consisted of sensory modalities (tactile threshold, touch, proprioception, stereognosis) and upper limb kinematics during reach-to-grasp of an object located near and far from the body (five assessments: three pre-intervention, immediately post-intervention and 3 mo post-intervention).

RESULTS

Motor improvements could be retained 3 months after the intervention and transferred to a similar task in children with CP. Proprioception and tactile thresholds were associated with retention of improvements in endpoint velocity (F2,13 =4.832, p=0.027).

INTERPRETATION

Practice of activities aimed at improving upper limb kinematics led to better learning and retention of movement patterns in children with CP. Our results underline the importance of sensation for motor learning in children with CP.

Deficits in elbow position sense in neonatal brachial plexus palsy

BACKGROUND

In neonatal brachial plexus palsy, sensory recovery is thought to exceed motor recovery with little attention paid to long-term assessment of proprioceptive ability. However, there is growing evidence that reduced somatosensory function frequently accompanies motor deficits as a result of activity-dependent changes in the central nervous system. Given the importance of proprioception in everyday motor activities, this study was designed to investigate position sense about the elbow joint in neonatal brachial plexus palsy.

METHODS

A convenience sample of seven individuals with neonatal brachial plexus palsy aged 9-17 years and in seven control individuals aged 10-16 years were recruited for the study. An elbow position matching task was used in which passive displacement of the forearm (reference arm) was reproduced with the same or opposite arm. In both conditions, matching was performed in the absence of vision and required utilization of position-related proprioceptive feedback.

RESULTS

Position-matching errors were significantly greater for the affected versus the unaffected arm when reproducing a reference position with the same arm. When matching was performed using the opposite arm, errors were dependent upon which arm served as the reference arm. When the unaffected arm served as the reference position, affected arm matching errors were not significantly different from control values. However, in the reverse situation, in which the unaffected arm relied on reference feedback from the affected arm, matching errors doubled compared with control values.

CONCLUSIONS

These results provide evidence that position sense is impaired in neonatal brachial plexus palsy and illustrate the importance of assessing proprioception in this population.

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.

Does somatosensory discrimination activate different brain areas in children with unilateral cerebral palsy compared to typically developing children? An fMRI study

Aside from motor impairment, many children with unilateral cerebral palsy (CP) experience altered tactile, proprioceptive, and kinesthetic awareness. Sensory deficits are addressed in rehabilitation programs, which include somatosensory discrimination exercises. In contrast to adult stroke patients, data on brain activation, occurring during somatosensory discrimination exercises, are lacking in CP children. Therefore, this study investigated brain activation with functional magnetic resonance imaging (fMRI) during passively guided somatosensory discrimination exercises in 18 typically developing children (TD) (age, M=14 ± 1.92 years; 11 girls) and 16 CP children (age, M=15 ± 2.54 years; 8 girls). The demographic variables between both groups were not statistically different. An fMRI compatible robot guided the right index finger and performed pairs of unfamiliar geometric shapes in the air, which were judged on their equality. The control condition comprised discrimination of music fragments. Both groups exhibited significant activation (FDR, p<.05) in frontoparietal, temporal, cerebellar areas, and insula, similar to studies in adults. The frontal areas encompassed ventral premotor areas, left postcentral gyrus, and precentral gyrus; additional supplementary motor area (SMA proper) activation in TD; as well as dorsal premotor, and parietal operculum recruitment in CP. On uncorrected level, p<.001, TD children revealed more left frontal lobe, and right cerebellum activation, compared to CP children. Conversely, CP children activated the left dorsal cingulate gyrus to a greater extent than TD children. These data provide incentives to investigate the effect of somatosensory discrimination during rehabilitation in CP, on clinical outcome and brain plasticity.

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.