Predicting task performance from upper extremity impairment measures after cervical spinal cord injury.

BACKGROUND: Automated sensor-based assessments of upper extremity (UE) function after cervical spinal cord injury (SCI) could provide more detailed tracking of individual recovery profiles than is possible with existing assessments, and optimize the delivery and assessment of new interventions. The design of reliable automated assessments requires identifying the key variables that need to be measured to meaningfully quantify UE function. An unanswered question is to what extent measures of sensorimotor impairment can quantitatively predict performance on functional tasks. OBJECTIVE: The objective was to define the predictive value of impairment measures for concurrent functional task performance in traumatic cervical SCI, as measured by the Graded Redefined Assessment of Strength, Sensibility and Prehension (GRASSP). SETTING: Retrospective analysis. METHODS: A data set of 138 GRASSP assessments was analyzed. The Strength and Sensation modules were used as measures of impairment, whereas the concurrent Prehension Performance module was used as the surrogate measure of function. Classifiers were trained to predict the scores on each of the six individual tasks in the Prehension Performance module. The six scores were added to obtain a total score. RESULTS: The Spearman's ρ between predicted and actual total Prehension Performance scores was 0.84. Predictions using both the Strength and Sensation scores were not found to be superior to predictions using the Strength scores alone. CONCLUSIONS: Measures of UE motor impairment are highly predictive of functional task performance after cervical SCI. Automated sensor-based assessments of UE motor function after SCI can rely on measuring only impairment and estimating functional performance accordingly.

Feasibility and efficacy of upper limb robotic rehabilitation in a subacute cervical spinal cord injury population.

STUDY DESIGN: Multi-center pilot study. OBJECTIVES: To investigate the use of an upper limb robotic rehabilitation device (Armeo Spring, Hocoma AG, Switzerland) in a subacute cervical spinal cord injury (SCI) population. SETTING: Two Canadian inpatient rehabilitation centers. METHODS: Twelve subjects (motor level C4-C6, ASIA Impairment Scale A-D) completed the training, which consisted of 16.1±4.6 sessions over 5.2±1.4 weeks. Two types of outcomes were recorded: (1) feasibility of incorporating the device into an inpatient rehabilitation program (compliance with training schedule, reduction in therapist time required and subject questionnaires) and (2) efficacy of the robotic rehabilitation for improving functional outcomes (Graded and Redefined Assessment of Strength, Sensibility and Prehension (GRASSP), action research arm test, grip dynamometry and range of motion). RESULTS: By the end of the training period, the robot-assisted training was shown to require active therapist involvement for 25±11% (mean±s.d.) of the total session time. In the group of all subjects and in a subgroup composed of motor-incomplete subjects, no statistically significant differences were found between intervention and control limbs for any of the outcome measures. In a subgroup of subjects with partial hand function at baseline, the GRASSP-Sensibility component showed a statistically significant increase (6.0±1.6 (mean±s.e.m.) point increase between baseline and discharge for the intervention limbs versus 1.9±0.9 points for the control limbs). CONCLUSION: The pilot results suggest that individuals with some preserved hand function after SCI may be better candidates for rehabilitation training using the Armeo Spring device.

Characterization of neurological recovery following traumatic sensorimotor complete thoracic spinal cord injury.

STUDY DESIGN: Retrospective, longitudinal analysis of sensory, motor and functional outcomes from individuals with thoracic (T2-T12) sensorimotor complete spinal cord injury (SCI). OBJECTIVES: To characterize neurological changes over the first year after traumatic thoracic sensorimotor complete SCI. METHODS: A dataset of 399 thoracic complete SCI subjects from the European Multi-center study about SCI (EMSCI) was examined for neurological level, sensory levels and sensory scores (pin-prick and light touch), lower extremity motor score (LEMS), ASIA Impairment Scale (AIS) grade, and Spinal Cord Independence Measure (SCIM) over the first year after SCI. RESULTS: AIS grade conversions were limited. Sensory scores exhibited minimal mean change, but high variability in both rostral and caudal directions. Pin-prick and light touch sensory levels, as well as neurological level, exhibited minor changes (improvement or deterioration), but most subjects remained within one segment of their initial injury level after 1 year. Recovery of LEMS occurred predominantly in subjects with low thoracic SCI. The sensory zone of partial preservation (ZPP) had no prognostic value for subsequent recovery of sensory levels or LEMS. However, after mid or low thoracic SCI, ≥3 segments of sensory ZPP correlated with an increased likelihood for AIS grade conversion. CONCLUSION: The data suggest that a sustained deterioration of three or more thoracic sensory levels or loss of upper extremity motor function are rare events and may be useful for tracking the safety of a therapeutic intervention in early phase acute SCI clinical trials, if a significant proportion of study subjects exhibit such an ascent.