HAND FUNCTION IN HEMIPLEGIA

Optimising rehabilitation and recovery after a stroke

Stroke can cause significant disability and impact quality of life. Multidisciplinary neurorehabilitation that meets individual needs can help to optimise recovery. Rehabilitation is essential for best quality care but should start early, be ongoing and involve effective teamwork. We describe current stroke rehabilitation processes, from the hyperacute setting through to inpatient and community rehabilitation, to long-term care and report on which UK quality care standards are (or are not) being met. We also examine the gap between what stroke rehabilitation is recommended and what is being delivered, and suggest areas for further improvement.

Recovery of Grasp versus Reach in People with Hemiparesis Poststroke

Background and Objective. The authors recently found that grasping was not relatively more disrupted than reaching in people with acute hemiparesis. They now extend this work to the recovery of reach versus grasp.

Methods. Hemiparetic subjects were tested acutely, after 90 days, and then after 1 year poststroke, and a control group was evaluated once. Using kinematic techniques, subjects were studied performing reach and reach-to-grasp movements. The authors quantified 3 characteristics of performance for each movement: speed, accuracy, and efficiency, where an efficient movement was defined as a movement directly to the target without extraneous or abnormally circuitous movements. To evaluate the relative deficits and recovery in reach versus grasp, performance measures were converted to z scores using control group means and standard deviations.

Results. The authors’ results showed that, starting with small deficits in speed acutely, both reach speed and grasp speed improved over time. Deficits in accuracy were greater in the reach than the grasp acutely, and these deficits lessened such that by the 90-day time point, the relative accuracy of the 2 movements was the same. In contrast, deficits in efficiency were greater in the grasp than the reach acutely, and grasp efficiency did not recover. The majority of recovery in reaching and grasping occurred by the 90-day time point, with little change occurring between the 90-day and 1-year time points.

Conclusions. The authors hypothesize that, in chronic hemiparesis, purposeful movements requiring distal control may be more impaired than purposeful movements requiring proximal control, not because of the initial lesion, but because, over the course of recovery, spared components of the descending motor systems may be able to compensate for the accuracy deficits in reaching (proximal control) but not the efficiency deficits in grasping (distal muscular control).

Revue et analyse d'instruments de mesure de la performance de la main et du membre supérieur

Les membres supérieurs jouent un rôle essentiel dans l'accomplissement des activités courantes de tout individu. Une atteinte de leur fonctionnement nécessite une évaluation précise pour guider l'application d'un programme de réadaptation. Afin d'aider le clinicien ou le chercheur à choisir un outil d'évaluation adapté à ses besoins et à ceux de la clientèle qui le préoccupe, 16 instruments de mesure de la performance de la main et du membre supérieur sont d'abord décrits, puis analysés selon des critères importants en milieu clinique et de recherche.

Differential effects of startle on reaction time for finger and arm movements

Recent studies using a reaction time (RT) task have reported that a preprogrammed response could be triggered directly by a startling acoustic stimulus (115-124 dB) presented along with the usual "go" signal. It has been suggested that details of the upcoming response could be stored subcortically and are accessible by the startle volley, directly eliciting the correct movement. However, certain muscles (e.g., intrinsic hand) are heavily dependent on cortico-motoneuronal connections and thus would not be directly subject to the subcortical startle volley in a similar way to muscles whose innervations include extensive reticular connections. In this study, 14 participants performed 75 trials in each of two tasks within a RT paradigm: an arm extension task and an index finger abduction task. In 12 trials within each task, the regular go stimulus (82 dB) was replaced with a 115-dB startling stimulus. Results showed that, in the arm task, the presence of a startle reaction led to significantly shorter latency arm movements compared with the effect of the increased stimulus intensity alone. In contrast, for the finger task, no additional decrease in RT caused by startle was observed. Taken together, these results suggest that only movements that involve muscles more strongly innervated by subcortical pathways are susceptible to response advancement by startle.

Relating Movement Control at 9 Upper Extremity Segments to Loss of Hand Function in People with Chronic Hemiparesis

Background and Objective . Loss of hand function in people with hemiparesis is a major contributor to disability poststroke. To use the hand for functional activities, a person may need control of the more proximal upper extremity segments to position and orient the hand with respect to the environment and may need control of the fingers to manipulate objects within the environment. The purpose of this project was to investigate how movement control at proximal, middle, and distal upper extremity segments contributed to loss of hand function in people with chronic hemiparesis. Methods. 32 patients with hemiparesis (avg 21.4 months postlesion) were studied making isolated movements of shoulder flexion, elbow flexion, forearm pronation/supination, wrist flexion/extension, and individual finger flexion using 3D kinematic techniques. For each segment, 3 variables were obtained: how far a segment could move (active range of motion [AROM]), how well a segment could move by itself (individuation index), and how well a segment could remain still when it was not supposed to move (stationary index). Hand function was measured with a battery of clinical tests, and principal components analysis was used to create a single hand function score for each patient from the test battery. Correlation and regression analyses were used to examine relationships between segmental movement control and hand function. Results. Movement control at all 9 segments of the upper extremity was related to hand function. Of the 9 segments, the thumb tended to have the weakest relationship with hand function. Of the 3 measures of movement control, AROM had strong relationships with and predicted the most variance in hand function (73%). Most of this variance was shared across segments, such that, for AROM, there were no unique contributions provided by proximal, middle, or distal segments. Conclusions. These data support the idea that loss of movement control covaries across segments and that loss of hand function is due to loss of movement control at all segments, not just at distal ones.

Deficits in grasp versus reach during acute hemiparesis

We studied how acute hemiparesis affects the ability to perform purposeful movements of proximal versus distal upper extremity segments. Given the gradient of corticospinal input to the spinal motoneuron pools, we postulated that movement performance requiring distal segment control (grasping) should be more impaired than movement performance requiring proximal segment control (reaching) in people with hemiparesis. We tested subjects with acute hemiparesis and control subjects performing reach and reach-to-grasp movements. Three characteristics of movement performance were quantified for each movement: speed, accuracy, and efficiency. For the reach, we calculated peak wrist velocity, endpoint error, and reach path ratio. For the grasp, we calculated peak aperture rate, aperture at touch, and aperture path ratio. To evaluate the relative deficits in reaching versus grasping, performance measures were converted to z-scores using control group means and standard deviations. For both the movements, movement times were longer and performance was more variable in the hemiparetic group compared to the control group. Hemiparetic z-scores indicated that relative deficits in movement speed were small in the two movements, with deficits in grasp being slightly greater than deficits in reach. Relative deficits in accuracy showed a trend for being larger in the reach compared to the grasp, but this difference did not reach statistical significance. In contrast, relative deficits in efficiency were larger in the grasp compared to the reach, with reaching efficiency near the range of normal performance. When considering data across all three movement characteristics, the ability to perform a purposeful movement with the distal segments was not clearly more disrupted than the ability to perform a purposeful movement with the proximal segments in people with acute hemiparesis.

Differential impairment of individuated finger movements in humans after damage to the motor cortex or the corticospinal tract

The purpose of this study was to quantify the long-term loss of independent finger movements in humans with lesions relatively restricted to motor cortex or corticospinal tract. We questioned whether damage to the motor cortex or corticospinal tract would permanently affect the ability to move each finger to the same degree or would affect some fingers more than others. People with pure motor hemiparesis due to ischemic cerebrovascular accident were used as our experimental sample. Pure motor hemiparetic and control subjects were tested for their ability to make cyclic flexion/extension movements of each finger independently. We recorded their finger joint motion using an instrumented glove. The fingers of control subjects and of the unaffected hands (ipsilateral to the lesion) of hemiparetic subjects moved relatively independently. The fingers of the affected hands (contralateral to the lesion) of hemiparetic subjects were differentially impaired in their ability to make independent finger movements. The independence of the thumb was normal; the independence of the index finger was slightly impaired, while the independence of the middle, ring, and little fingers was substantially impaired. The differential long-term effects of motor cortical or corticospinal damage on finger independence may result from rehabilitative training emphasizing tasks requiring independent thumb and index movements, and from a greater ability of the spared components of the neuromuscular system to control the thumb independently compared with the other four fingers.

Upper limb motor function in hemiparesis: concurrent validity of the Arm Motor Ability test

OBJECTIVE

To evaluate the concurrent validity of the Arm Motor Ability Test (AMAT) using the Fugl-Meyer Assessment (FMA) as the criterion measure of poststroke upper limb motor impairment.

DESIGN

Upper limb motor impairment and arm ability of 30 chronic stroke survivors were assessed with the FMA and AMAT, respectively. Spearman's correlation coefficients were generated relating the components of FMA and AMAT. Scatterplots were generated to provide qualitative assessments of the relationship between FMA and AMAT. Bar graphs of FMA and AMAT normalized to their maximum scores were generated to compare the levels of motor status measured by each instrument.

RESULTS

All components of AMAT correlated highly with FMA total (r = 0.92-0.94; P < 0.001). AMAT functional ability and AMAT quality of movement were linearly related with FMA total. However, AMAT time of performance exhibited significant ceiling and floor effects with respect to FMA. Normalized AMAT scores were generally lower than normalized FMA scores (P < 0.001), with the greatest difference in scores observed in subjects with more severe motor impairments.

CONCLUSION

This study demonstrates a high degree of concurrent criterion validity of the AMAT. However, AMAT tends to underestimate the arm motor status of those with more severe motor impairments.

Motor impairment as a predictor of functional recovery and guide to rehabilitation treatment after stroke

OBJECTIVE

This study tests three hypotheses relevant for the efficient use of rehabilitation services after stroke: (a) the severity of initial motor impairment after stroke predicts discharge motor impairment and self-care mobility scores; (b) identification of those unlikely to show improvement in motor impairment can focus rehabilitzation efforts on use of compensatory techniques and assist devices; and (c) improvement in self-care mobility scores without change in motor impairment, balance, or cognition is a quantitative estimate of the value of teaching compensatory techniques and use of assist devices.

METHODS

We studied 171 sequential patients previously independent in the community who were admitted for inpatient rehabilitation within 17 +/- 12 SD days of an initial, unilateral, hemispheric, ischemic stroke. Impairment was assessed using the Fugl-Meyer upper limb motor (ULM), lower limb motor (LLM), and upper plus lower limb total motor (TM) subscores. Disability was assessed using the Functional Independence Measure (FIM), FIM self-care (FIMS), FIM mobility (FIMM), and FIM self-care plus FIM mobility (FIMSM) subscores. Spearman correlation coefficients tested strength of association between dependent and independent variables, stepwise linear regression tested the effects of clinically relevant co-variables, and positive and negative predictive values (PPV, NPV) assessed the clinical relevance of outcome-prediction models.

RESULTS

The highest correlations observed were between admission TM scores and the following discharge scores: TM (R = 0.92; p < 0.01), ULM (R = 0.91; p < 0.01), LLM (R = 0.82; p < 0.01), FIMSM (R = 0.67; p < 0.01), FIMM (R = 0.67; p < 0.001), FIM (R = 0.58; p < 0.0001). An admission TM score in the lowest quartile had a PPV of 0.74 for a discharge ULM score in the lowest quartile. An admission TM score in the highest quartile had a PPV of 0.86 for a discharge ULM score in the highest quartile. Similar but weaker PPVs were seen for admission TM scores and discharge LLM scores. Patients without significant change in TM scores (< or = 2 points) had a 17 +/- 9 SD improvement in FIMSM scores.

CONCLUSIONS

Admission motor impairment scores (a) predict discharge impairment and activities of daily living mobility functional outcome; and (b) guide treatment toward improving motor impairment versus use of compensatory techniques and assistive devices. The use of compensatory techniques and assistive devices, without change in motor impairment, is associated with a 17 +/- 9 SD improvement in FIMSM score.

Shoulder shrug--a prognostic sign for recovery of hand movement after stroke

A new clinical sign with prognostic significance for recovery of hand movements after stroke is described. Thirty-two patients with hemispheric cerebrovascular accident were assessed to determine whether the ability to shrug the hemiplegic shoulder at initial assessment correlated with the recovery of hand movements. The results of 29 of these patients with poor hand movements at initial assessment were analysed. Of 18 patients with absent shoulder shrug, only two patients (11%) showed return of good active movements in the involved hand at final evaluation, whereas eight (73%) of 11 patients who could shrug the hemiplegic shoulder at initial assessment went on to recover good movements in the hand (P = 0.00). In a subgroup of patients who demonstrated only synergistic flexion of fingers in the hemiplegic hand, one of five patients with absent shoulder shrug showed good hand movements at the final assessment in contrast to six of seven patients who initially could shrug the hemiplegic shoulder. Only one of 15 patients who showed total absence of hand movements at the initial assessment had a return of good hand movements. The data suggest that clinical assessment of shoulder shrug is a good prognostic indicator for recovery of voluntary movements in the hemiplegic hand especially when any hand movement, even if it is only synergistic finger flexion, is present at initial assessment. Total absence of hand movements at initial assessment is a poor prognostic sign.

Measuring arm impairment and disability after stroke

This is a review of the problems of assessing impairments and disabilities affecting the arm after stroke, and of the various published measures already available. In routine clinical practice, motor impairment is best assessed using grip strength or the Motricity Index, and dexterity disability is best assessed using the Nine-Hole Peg Test or Ten-Hole Peg Test. No measures of sensation and tone are specifically recommended, primarily because validity and reliability has not been well established for the measures available. Other more complex tests appropriate for more detailed use in planning treatment or in research are discussed.

Arm function after stroke: measurement and recovery over the first three months

Four short, simple measures of arm function, suitable for use with patients recovering from acute stroke, are described. These tests are: the Frenchay Arm Test, the Nine Hole Peg Test, finger tapping rate and grip strength. Good interobserver and test-retest reliability was demonstrated for all tests, and the Frenchay Arm Test was shown to be valid. Normal values for all tests were established on 63 controls. It was found that the limited sensitivity of the Frenchay Arm Test could be improved using the Nine Hole Peg Test and grip strength. Recovery of arm function has been studied in a sample of 56 patients seen regularly over the first 3 months after their stroke, using these standard measures. The results demonstrated a wide variation in recovery curves between patients. The use of the Nine Hole Peg Test enabled further recovery to be detected after patients achieved a top score on the Frenchay Arm Test. Failure to recover measureable grip strength before 24 days was associated with absence of useful arm function at three months. Measurement of finger tapping rate was not useful.

Loss of arm function after stroke: measurement, frequency, and recovery

This study aims to establish the frequency of paralysis and other arm problems after stroke; the recovery of lost function; and to compare various tests of the affected arm. Thirteen per cent of the sample had no arm paralysis when first seen within 14 days. At 3 months 24 per cent of survivors had moderate or severe paralysis; 57 per cent could place nine pegs into holes within 50 seconds; 19 per cent had significant sensory disturbance; 5 per cent had shoulder pain; 8 per cent had restricted passive shoulder movement; and 17 per cent had some paralysis of the dominant arm. Between 3 and 6 months, improvement of motor power was seen in 40 per cent of patients, and 13 per cent of patients improved their function. Severity of initial paralysis was an important prognostic factor.

The hemiplegic arm after stroke: measurement and recovery

Seven clinical tests have been used to study the recovery of arm function in 92 patients over 2 years following their stroke. These tests are simple and quick, and can be used by any interested observer. They form a hierarchical scale that measures recovery. Statistically significant improvement is only seen in the first 3 months. Fifty-six patients initially had non-functional arms; eight made a "complete recovery" and 14 a partial recovery. The tests described are inadequate on their own because they are not sufficiently sensitive at the upper range of ability. While recovery of lost function does relate to the degree of initial neurological loss in the arm, it seems to be largely independent of the overall severity of the stroke.