After a stroke, it is essential that recovery of function of the upper limb is maximized in order to enable activities of daily living. The hand plays an important role in the function of the upper limb. This study examined the effectiveness of contralaterally controlled functional electrical stimulation (CCFES) on recovery of active dorsiflexion of the wrist and upper limb functioning in patients in the early-phase after stroke (<15 days post-stroke). CCFES significantly shortened the time for regaining wrist dorsiflexion, and improved the upper extremity function and general health of patients with early-phase stroke, compared with conventional neuro-muscular electrical stimulation. CCFES therefore has potential as a clinical intervention.
Stroke is a leading cause of disability with high morbidity and mortality. Approximately 75% of patients with stroke have upper extremity dysfunction (1). Impaired motor function of the upper extremity is a major factor in preventing patients returning to their usual activities. In addition to routine medical treatment, early-phase rehabilitation helps improve motor function and activities of daily living (ADL) (2). Moreover, well-prescribed rehabilitation may shorten the course of recovery from stroke, help patients return to the community earlier, improve their quality of life, and reduce the cost of medication (3).
Recovery of upper extremity functioning is essential for improving ADL ability in patients with stroke (4). The hands play an important role in functioning of the upper extremities. Hand function and, in particular, extensor function, is difficult to recover once impaired, Therefore, specific rehabilitation interventions, which are considered the first step in re-gaining full extension of the hand, are essential in the recovery of wrist dorsiflexion (WD). Early recovery of active WD contributes not only to a better outcome for upper extremity functioning, but also to improved outcome for ADL.
Over the past decades, neuromuscular electrical stimulation (NMES), an electrical stimulation that provides passive training for the wrist dorsi-extensor, has been integrated into certain specific rehabilitation prescriptions (5–7). NMES triggers the movement using electrical stimulation. The frequency and amplitude of biphasic rectangular current pulses are pre-set and fixed during the whole training course.
In contrast, controlled functional electrical stimulation (CCFES) is an intervention technique developed recently to improve the function of the paretic upper extremity after stroke. One of the characteristics of CCFES is that it requires active participation from patients, and not merely electrical stimulation of the paretic muscle or extremity. As described by Knutson et al., “CCFES uses a control signal from the non-paretic side of the body to regulate the intensity of electrical stimulation delivered to the paretic muscles of the homologous limb on the opposite side of the body” (8). In separate studies, Knutson et al. (9) and Shen et al. (10) compared the effectiveness of CCFES and NMES in patients with sub-acute stoke, and found greater improvements with CCFES. Nonetheless, its effectiveness in the early-phase (i.e. within 15 days) after stroke is unclear. The aim of this study was therefore to investigate the effectiveness of CCFES compared with NMES on upper extremity function, particularly WD, in patients with early-phase stroke.
Patients admitted to the Department of Neurology, Jiangsu Province People’s Hospital, Nanjing, China, between March and September 2015 were recruited to this study. All subjects provided written informed consent prior to the study, and the ethics committee of the First Affiliated Hospital of Nanjing Medical University approved the study protocol.
Inclusion criteria were: (i) diagnosed with stroke using computed tomography (CT) or magnetic resonance imaging (MRI); (ii) stable vital signs 48 h post-stroke; (iii) single-side injury; (iv) age 20–80 years; (v) within 15 days post-stroke; (vi) Brunnstrom recovery stage of III or less; (vii) score of Fugl-Meyer assessment (FMA) for upper extremity ≤ 22; and (viii) no active WD detected.
Exclusion criteria were: (i) progressive stroke with non-stable condition; (ii) stroke-like symptoms due to subdural haematoma, tumour, encephalitis or trauma; (iii) unable to follow treatment instructions due to severe cognitive and communication deficiency; (iv) implanted with a pacemaker; and (v) no informed consent (11).
Patients were assigned to either the NMES or the CCFES group based on a computer-generated randomization list and allocation (1:1) concealed by consecutively numbered, sealed opaque envelopes. An envelope was opened once a patient had consented to participate in the trial, the administrator then informed the doctor about the allocated intervention regimen via phone calls.
In the NMES group, 2 stimulating electrodes (4 × 4 cm) were placed at the motor points of the forearm extensor muscles (specifically the ulnar margin of the extensor aspect of the forearm) to produce WD (Fig. 1a). The stimulators (Weisi Corporation, Nanjing, China) used in this study delivered biphasic rectangular current pulses; the pulse frequency was set at 35 Hz, and the pulse amplitude was set at 40 mA. The electrical stimulation intensity was set at a sustainable level with full balanced WD with tetanic contraction.
In the CCFES group, 3 recording electrodes (4 × 4 cm) were placed on the motor points of the forearm extensor muscles (the ulnar margin of the extensor aspect of the forearm) on the non-paretic side, while 2 stimulating electrodes (4 × 4 cm) were attached on the paretic side (Fig 1b). For each patient, the intensity of the electrical stimulation to WD of the paretic side was determined by the strength of contralateral forearm extensor muscles contraction. Subjects were asked to voluntarily extend their unaffected wrist to 10% of ROM or less and maintain that position without moving. The electromyography value of the movement was then recorded. Meanwhile, the therapist adjusted the electric intensity until the same degree of movement appeared on the paretic side. The intensity value was then recorded. The same practice and recording process was also applied, with the patients extending their unaffected wrist to 50% and 100% of ROM. The electrical stimulation intensity that produced balanced WD was determined empirically for each patient and programmed into the stimulator.
Fig. 1. Patients treated with different strategies. (a) The patient underwent neuromuscular electrical stimulation (NMES) with the stimulator in Model I; (b) the patient underwent contralaterally controlled functional electrical stimulation (CCFES) with the stimulator in Model II.