Background and Objective. Favorable prognosis of the upper limb depends on preservation or return of voluntary finger extension (FE) early after stroke. The present study aimed to determine the effects of modified constraint-induced movement therapy (mCIMT) and electromyography-triggered neuromuscular stimulation (EMG-NMS) on upper limb capacity early poststroke.
Methods. A total of 159 ischemic stroke patients were included: 58 patients with a favorable prognosis (>10° of FE) were randomly allocated to 3 weeks of mCIMT or usual care only; 101 patients with an unfavorable prognosis were allocated to 3-week EMG-NMS or usual care only. Both interventions started within 14 days poststroke, lasted up until 5 weeks, focused at preservation or return of FE.
Results. Upper limb capacity was measured with the Action Research Arm Test (ARAT), assessed weekly within the first 5 weeks poststroke and at postassessments at 8, 12, and 26 weeks. Clinically relevant differences in ARAT in favor of mCIMT were found after 5, 8, and 12 weeks poststroke (respectively, 6, 7, and 7 points; P < .05), but not after 26 weeks. We did not find statistically significant differences between mCIMT and usual care on impairment measures, such as the Fugl-Meyer assessment of the arm (FMA-UE). EMG-NMS did not result in significant differences.
Conclusions. Three weeks of early mCIMT is superior to usual care in terms of regaining upper limb capacity in patients with a favorable prognosis; 3 weeks of EMG-NMS in patients with an unfavorable prognosis is not beneficial. Despite meaningful improvements in upper limb capacity, no evidence was found that the time-dependent neurological improvements early poststroke are significantly influenced by either mCIMT or EMG-NMS.
Several prospective cohort studies among stroke patients have shown that the functional outcome of the upper limb is largely defined within the first 5 weeks poststroke and is mainly driven by (yet poorly understood) mechanisms of spontaneous neurological recovery.1,2 Observational studies showed that the presence of some voluntary finger extension (FE) within 72 hours is a favorable indicator for the return of dexterity poststroke.3,4 This suggests that early control of FE is an important prognostic factor in stratifying patients for upper limb intervention trials early poststroke.2
For those with a favorable prognosis, indicated by some voluntary FE early poststroke, constraint-induced movement therapy (CIMT) or a modified version (mCIMT) may benefit arm-hand activities and self-reported hand function in daily life.5The number of phase II trials on mCIMT within the first days or weeks poststroke is however small and findings are rather inconclusive. For example, Dromerick et al6showed in a proof of concept trial that 1 or 2 hours mCIMT per working day for 2 weeks was not superior to an equal dosage of usual care, whereas a high dose of 3 hours mCIMT per working day resulted in less improvement on functional outcome measured with the Action Research Arm Test (ARAT) at 3 months poststroke.
For those with an unfavorable prognosis for functional outcome at 6 months, that is, patients without voluntary FE,1,3,4 no evidence-based therapies have been reported so far. In subacute and chronic stroke, innovative therapies such as electromyography-triggered neuromuscular stimulation (EMG-NMS) of the finger extensors to improve voluntary control have shown promise in terms of increasing active range of motion.7⇓⇓⇓–11 Furthermore, several studies suggest that EMG-NMS may produce changes in cortical activation patterns and excitability in chronic stroke.12,13 For example, Shin et al13 showed in a small proof of concept trial (n = 14) that a daily 30-minute program for 10 weeks shifted cortical activation patterns as seen in functional magnetic resonance imaging from the ipsilateral sensorimotor cortex to the contralateral sensorimotor cortex in chronic stroke. Despite the growing evidence for enhanced levels of homeostatic neuroplasticity in the first weeks poststroke,14 early started EMG-NMS trials for patients without FE are lacking in this restricted time window.
The first objective of the present study was to investigate the effects of an early mCIMT program on recovery of upper limb capacity during the first 6 months, starting within 14 days poststroke in patients with some voluntary FE. Our second objective was to investigate the effects of early EMG-NMS on the recovery of voluntary FE and upper limb capacity during the first 6 months, starting within 14 days poststroke in patients with no voluntary control of the finger extensors. We hypothesized that an intensive 3-week mCIMT program would result in a clinically meaningful improvement in ARAT scores compared with usual care alone. For the patients with an unfavorable prognosis we hypothesized that a higher percentage of patients (10% or more increase) would regain some dexterity (ARAT score >9 points on a maximum of 57 points) if they received intensive daily EMG-NMS for 3 weeks, compared with usual care alone.