The effect of altered hand position and motor skills on stereognosis

Learning of Artificial Sensation Through Long-Term Home Use of a Sensory-Enabled Prosthesis

Upper limb prostheses are specialized tools, and skilled operation is learned by amputees over time. Recently, neural prostheses using implanted peripheral nerve interfaces have enabled advances in artificial somatosensory feedback that can improve prosthesis outcomes. However, the effect of sensory learning on artificial somatosensation has not been studied, despite its known influence on intact somatosensation and analogous neuroprostheses. Sensory learning involves changes in the perception and interpretation of sensory feedback and may further influence functional and psychosocial outcomes. In this mixed methods case study, we examined how passive learning over 115 days of home use of a neural-connected, sensory-enabled prosthetic hand influenced perception of artificial sensory feedback in a participant with transradial amputation. We examined perceptual changes both within individual days of use and across the duration of the study. At both time scales, the reported percept locations became significantly more aligned with prosthesis sensor locations, and the phantom limb became significantly more extended toward the prosthesis position. Similarly, the participant’s ratings of intensity, naturalness, and contact touch significantly increased, while his ratings of vibration and movement significantly decreased across-days for tactile channels. These sensory changes likely resulted from engagement of cortical plasticity mechanisms as the participant learned to use the artificial sensory feedback. We also assessed psychosocial and functional outcomes through surveys and interviews, and found that self-efficacy, perceived function, prosthesis embodiment, social touch, body image, and prosthesis efficiency improved significantly. These outcomes typically improved within the first month of home use, demonstrating rapid benefits of artificial sensation. Participant interviews indicated that the naturalness of the experience and engagement with the prosthesis increased throughout the study, suggesting that artificial somatosensation may decrease prosthesis abandonment. Our data showed that prosthesis embodiment was intricately related to naturalness and phantom limb perception, and that learning the artificial sensation may have modified the body schema. As another indicator of successfully learning to use artificial sensation, the participant reported the emergence of stereognosis later in the study. This study provides the first evidence that artificial somatosensation can undergo similar learning processes as intact sensation and highlights the importance of sensory restoration in prostheses.

Validity and Responsiveness of the Revised Nottingham Sensation Assessment for Outcome Evaluation in Stroke Rehabilitation

OBJECTIVE. This study establishes the concurrent validity, predictive validity, and responsiveness of the Revised Nottingham Sensation Assessment (rNSA) during rehabilitation for people with stroke.

METHOD. The study recruited 147 patients with stroke. The main assessment used was the rNSA, and outcome measures were the Fugl-Meyer Assessment sensory subscale (FMA–S) and motor subscale (FMA–M) and the Nottingham Extended Activities of Daily Living (NEADL) scale.

RESULTS. Correlation coefficients were good to excellent between the rNSA and the FMA–S. The rNSA proprioception measure was a predictor for the FMA–S. The rNSA stereognosis and tactile-pinprick measures for the proximal upper limb were predictors for the FMA–M and the NEADL scale, respectively. Responsiveness was moderate to large for three subscales of the rNSA (standardized response mean = .51–.83).

CONCLUSION. This study may support the concurrent validity, predictive validity, and responsiveness of the rNSA for people with stroke.

The Effect of Treatment on Stereognosis in Children With Hemiplegic Cerebral Palsy

PURPOSE

To determine if rehabilitation alone or combined with surgery or botulinum toxin injection improved stereognosis in children with hemiplegic cerebral palsy.

METHODS

Inclusion criteria were children with spastic hemiplegic cerebral palsy who had stereognosis testing 2 separate times with documentation of intervening treatment. Sixty-three children were included, 30 girls and 33 boys at an average age of 9.1 years (range, 4.4-16.0 years). Twelve standardized objects were used for manual identification. Baseline and postintervention stereognosis results were recorded for the hemiplegic and the dominant limb of each patient. The patients were separated into 3 groups based on intervening treatment: surgery with rehabilitation (27 patients), botulinum toxin injection with rehabilitation (19 subjects), and rehabilitation alone (7 subjects). Results were also analyzed by patient age group.

RESULTS

Baseline testing of the hemiplegic limb revealed that 27 patients (43%) exhibited severe stereognosis impairment (0-4 objects identified correctly), 18 (28%) were moderately impaired (5-8 objects), 13 (21%) were mildly impaired (9-11 objects), and 5 (8%) had intact stereognosis (12 objects). There was no statistically significant difference in change in stereognosis scores postintervention among the 3 different treatment groups or between patients who had surgery and those who did not have surgery. There was no statistically significant difference in stereognosis function or postintervention change based on patient age at time of testing.

CONCLUSIONS

In this study, 92% of children with spastic hemiplegic cerebral palsy had stereognosis impairment with a wide spectrum of severity. After operative or nonoperative treatment interventions, stereognosis as a secondary outcome measure was not changed.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic III.

Hand functioning in children with cerebral palsy

Brain lesions may disturb hand functioning in children with cerebral palsy (CP), making it difficult or even impossible for them to perform several manual activities. Most conventional treatments for hand dysfunction in CP assume that reducing the hand dysfunctions will improve the capacity to manage activities (i.e., manual ability, MA). The aim of this study was to investigate the directional relationships (direct and indirect pathways) through which hand skills influence MA in children with CP. A total of 136 children with CP (mean age: 10 years; range: 6–16 years; 35 quadriplegics, 24 diplegics, 77 hemiplegics) were assessed. Six hand skills were measured on both hands: touch-pressure detection (Semmes–Weinstein esthesiometer), stereognosis (Manual Form Perception Test), proprioception (passive mobilization of the metacarpophalangeal joints), grip strength (GS) (Jamar dynamometer), gross manual dexterity (GMD) (Box and Block Test), and fine finger dexterity (Purdue Pegboard Test). MA was measured with the ABILHAND-Kids questionnaire. Correlation coefficients were used to determine the linear associations between observed variables. A path analysis of structural equation modeling was applied to test different models of causal relationships among the observed variables. Purely sensory impairments did seem not to play a significant role in the capacity to perform manual activities. According to path analysis, GMD in both hands and stereognosis in the dominant hand were directly related to MA, whereas GS was indirectly related to MA through its relationship with GMD. However, one-third of the variance in MA measures could not be explained by hand skills. It can be concluded that MA is not simply the integration of hand skills in daily activities and should be treated per se, supporting activity-based interventions.

Assessment of the hand in cerebral palsy

Cerebral palsy is the musculoskeletal manifestation of a nonprogressive central nervous system lesion that usually occurs due to a perinatal insult to the brain. Though the cerebral insult is static the musculoskeletal pathology is progressive. Some patients with cerebral palsy whose hands are affected can be made better by surgery. The surgical procedures as such are not very technically demanding but the assessment, decision-making, and selecting the procedures for the given patient make this field challenging. When done well, the results are rewarding not only in terms of improvement in hand function but also in appearance and personal hygiene, which leads to better self-image and permits better acceptance in the society. This article focuses on the clinical examination, patient selection, and decision-making while managing these patients.

Tactile assessment in children with cerebral palsy: a clinimetric review

This review evaluates the clinimetric properties of tactile assessments for children with cerebral palsy. Assessment of registration was reported using Semmes Weinstein Monofilaments (SWMs) or exteroception. Assessment of two-point discrimination was reported using the Disk-Criminator® or paperclip methods; Single point localization and double simultaneous were reported from the Neurosensory Motor Developmental Assessment (NSMDA); graphaesthesia was reported from the Sensory Integration and Praxis Test (SIPT); and stereognosis was assessed using Manual Form Perception from the SIPT and the Klingels method (Klingels, K. et al. (2010). Upper limb motor and sensory impairments in children with hemiplegic cerebral palsy. Can they be measured reliably? Disability and Rehabilitation, 32(5), 409-416) and the Cooper method (Cooper, J., Majnemer, A., Rosenblatt, B., & Birnbaum, R. (1995). The determination of sensory deficits in children with hemiplegic cerebral palsy. Journal of Child Neurology, 10, 300-309). The SIPT and NSMDA demonstrated stronger content validity. Inter-rater reliability was excellent for SIPT (ICC = 0.99) and exteroception (k = 0.88). Test-retest reliability was excellent for exteroception (k = 0.89) and stereognosis (ICC = 0.86; 100%), moderate for SIPT (r = 0.69-0.74) and poor for SWM (k = 0.22). Together these assessments measure tactile registration and spatial perception. Temporal and textural tests are to be developed for comprehensive tactile examination.

Correlation of motor function and stereognosis impairment in upper limb cerebral palsy

PURPOSE

To correlate motor function, as measured by the Jebsen-Taylor test, and sensory function, as measured by the 12-object stereognosis testing, in the hands of children with spastic hemiplegia due to cerebral palsy.

METHODS

A chart review identified children with hemiplegic and triplegic cerebral palsy with stereognosis and Jebsen-Taylor testing between 1997 and 2008. Forty-one children were included in the study, including 22 girls and 19 boys, with an average age of 8.7 years (range, 6-16 years). The right side is affected in 23 children; 34 children have hemiplegic cerebral palsy, and 7 have triplegic cerebral palsy. The initial Jebsen-Taylor and stereognosis test results were recorded for each subject, as well as age, diagnosis, affected side, and prior treatment with hand therapy, botulinum toxin injection, or surgery. Descriptive statistics, chi-square analysis, paired t-tests, and correlation measurements were used for analysis of the data.

RESULTS

Statistically significant inverse correlations exist between the cards, small objects, checkers, light objects, and heavy objects on the Jebsen-Taylor subtests, as correlated with the stereognosis scores in the affected hand (p < or = 0.04). The stereognosis scores for the patients who were not able to complete the Jebsen-Taylor test with the affected hand were significantly lower than those who were able to complete the Jebsen-Taylor test with the affected hand (p = .04). The stereognosis scores were significantly lower for the affected side as compared with the contralateral side. The Jebsen-Taylor total test times were significantly longer for the affected side as compared with the contralateral side (p < .001).

CONCLUSIONS

In children with hemiplegic and triplegic cerebral palsy, the impairment of stereognosis is correlated with impairment in motor function, and the inability to complete the Jebsen-Taylor test with the affected hand is associated with impaired stereognosis function.

TYPE OF STUDY/LEVEL OF EVIDENCE

Prognostic IV.

Tendon transfers and releases for the forearm, wrist, and hand in spastic hemiplegic cerebral palsy

Cerebral Palsy (CP) is a static disorder of movement and posture secondary to an insult to the developing central nervous system. The peripheral manifestations and functional impairments of this condition vary in severity from mild-to-profound. In hemiplegic CP, 1 side of the body is affected more than the other. Spastic hemiplegia is the most common type and that for which upper extremity surgery is most indicated. Treatment options range from physical therapy and splinting to botulinum toxin A injections (Botox) to tendon transfers to arthrodeses. This article will discuss the indications, preoperative evaluation, our preferred surgical technique, and postoperative protocol for the most commonly used tendon transfers in the upper extremity in spastic hemiplegia.