Interventions for retraining gait

Strategies for retraining gait start with interventions to improve control of the head and trunk when nec- essary, then proceed to sitting and standing balance (Chapter 8 of Volume II). Practice paradigms ought to include a clear schedule and form of reinforcement (Chapter 7 of Volume II). Rehabilitation approaches for walking are listed in Table 3.1. Locomotor inter- ventions are limited only by the imagination of the rehabilitation team. An eclectic problem-solving approach is taken by most therapists. Walkers, canes, ankle–foot orthoses, and on occasion, knee–ankle– foot braces are used to improve balance, lessen the need for full lower extremity weight support, and aid foot clearance and knee control. A trial-and-error approach for fitting and employing these aids and a reassessment over the time of improved motor con- trol is usually needed. For step-training per se, as well as confounders such as hemi-inattention, lat- eral pulsion (pusher syndrome), truncal ataxia, gait apraxia, and extrapyramidal features, no particular style of care has been shown to be better than another, but few comparisons have been made. Anti-spasticity agents and intramuscular botulinum toxin may improve aspects of the gait cycle, primarily in patients with excessive plantar flexion/inversion.

Several of the approaches in Table 3.1 are being tested in randomized clinical trials (RCTs).

Task-oriented training

Body weight-supported treadmill training (BWSTT) is partially derived from treadmill training experiments on spinal transected animals and CPGs (Barbeau, 2003). It also provides task-oriented, massed practice under more optimal conditions for managing weight bearing and walking speed (Dobkin, 1999; Sullivan

et al., 2002). Forms of BWSTT have been employed after SCI, stroke, cerebral palsy (Schindl et al., 2000), multiple sclerosis (Lord et al., 1998), and Parkinson’s disease (Miyai et al., 2002).

Reviews and some initial reports of BWSTT after SCI often suggest that the beneficial effect of locomotor training in incomplete SCI patients is “well estab- lished” and that “even chronic SCI patients who underwent locomotor training had greater mobility compared with a control group with conventional rehabilitation” (Dietz and Harkema, 2004). The studies that are usually quoted have not, however, included control subjects at all (Field-Fote, 2001; Barbeau, 2003) or they employed “historical” controls (Wernig et al., 1995). Only one trial with clinically meaningful outcome measures obtained by blinded

Table 3.1. General approaches for retraining walking.

• Bobath, NDT, et al. to improve head and trunk control, balance, stance

• Progression from parallel bars; correct qualitative gait deviations

• Massed practice of walking • Braces and assistive devices

• Increase muscle strength (Moreland et al., 2003) • Increase walking speed and distance

• Reverse deconditioning (Teixeira-Salmela et al., 1999; MacKay-Lyons and Makrides, 2002)

• Task-specific shaping of more selective movements (Taub et al., 2002)

• Treadmill training
body weight support • Circuit training (Dean et al., 2000)

• Functional electrical stimulation for reflexive flexion or to fire a critical muscle group during the step cycle (Daly and Ruff, 2000; Loeb and Richmond, 2001; Herman et al., 2002) • Robotic and electromechanical assists for stepping (Hesse

et al., 2003)

• Pharmacological adjuncts for learning or neuromodulation • Biofeedback – kinematic or EMG
induced muscle

stimulation (Moreland et al., 1998; Sinkjaer et al., 2000) • Practice in virtual environments

• Imagery (Lafleur et al., 2002; Malouin et al., 2004) • Increase cortical excitation during practice (Dobkin,

2003b) – peripheral nerve, transcranial magnetic or direct motor cortex stimulation

observers has been reported, and that revealed no benefit of BWSTT over conventional care in incom- plete subjects. The SCI Locomotor Trial (SCILT) randomized 145 subjects with incomplete SCI who could not walk on admission to six regional SCI facilities. Subjects received 12 weeks of BWSTT complemented by over ground training when feasi- ble or an equal amount of conventional over ground training, in addition to usual inpatient and outpa- tient therapies (Dobkin et al., 2003). Table 3.2 is an overview of the results for ASIA C and D subjects with upper motor neuron impairments. No benefit of the intervention was found for ASIA B subjects, most of whom did not recover any ability to walk, or to ASIA C and D subjects, most of whom did walk at remarkably functional speeds and distances (Dobkin et al., 2004).

In patients who cannot stand and yet have some proximal motor control that may be brought out by an upright posture, BWSTT may enable some load- ing and foster rhythmic stepping. For example, the patient whose fMRI is shown in Fig. 3.1 was enabled to stand upright, bear some weight in the legs, and activate the iliopsoas and quadriceps muscles recip- rocally 3 months after the SCI, when he could not

stand or step after routine rehabilitation. The upright posture and leg assistance allowed him to concentrate on finding some motor control over residual descending pathways to surviving motoneu- rons that still innervated these muscles. Training and neuromuscular activity may then drive cerebral control for gait over various surfaces and speeds. Trophic substances produced by activity can increase peripheral axon regeneration to re-innervate mus- cle. (Dobkin and Havton, 2004). As interesting as this recovery seems, the same result may have been possible using more aggressive conventional therapies.

BWSTT when instituted a mean of 70 days after acute hemiparetic stroke revealed statistically sig- nificant gains in gait when compared to treadmill training without BWS (Visintin et al., 1998; Barbeau and Visintin, 2003). This comparison is of interest, but not a clinically useful distinction for evidence- based practices. Also, the outcomes were statisti- cally significant for walking speed, but not clinically significant. Other RCTs of BWSTT during acute inpatient rehabilitation after stroke revealed no clinical benefits for walking independence or speed (Nilsson et al., 2002; Lennihan et al., 2003). RCTs are needed to determine if BWSTT ought to be offered to patients who cannot walk over ground with a reciprocal gait or to those who still walk too slowly to ambulate outside of the home (50 cm/s) more than 6 months after onset of hemiplegic stroke or SCI in ASIA C subjects. Such trials will need to estab- lish training scenarios for the manipulation of BWS and treadmill speeds, along with justifying the duration and intensity of treatment. Even greater attention will be necessary for the design of RCTs of BWSTT augmented by robotic assistive devices (Colombo et al., 2000; Werner et al., 2002), func- tional electrical stimulation (Hesse et al., 1995; Chaplin, 1996; Barbeau et al., 2002), and pharmaco- logical interventions (Norman et al., 1998; Dobkin, 2003a). Dose–response studies for the amount of training, as is typically required for drug studies, and a demonstration of the reproducibility of train- ing techniques will require considerable pilot data (Dobkin, 2004).

Table 3.2. Six-month outcomes for a clinical trial of BWSTT versus conventional mobility training for 60 ASIA C and D subjects randomized within 8 weeks of SCI, graded at time of admission for rehabilitation.

BWSTT CONV

FIM walking score (0–7) 5.8
1.2 5.6
1.9 LEMS (0–50) 43
10 41
12 Walking speed (ft/s) 1.9 2.5

Median 3.3 3.8

FIM total motor score 85
15 86
17 6-min walk (ft) 1125
618 1197
564 WISCI (0–20) 15
5 14
7

Median 18 18

Berg balance (0–58) 44
19 43
19

Median 52 55

CONV: conventional physical therapy; LEMS: lower extremity motor score.

Pulse therapies

The efficacy of a pulse of various training strategies for walking has been demonstrated in well-designed trials from months to years after stroke (Hesse et al., 1994; Sullivan et al., 2002; Ada et al., 2003; Duncan et al., 2003b) and other chronically disabling neuro- logical diseases. The duration of effect will be limited in progressive diseases. That should not dissuade the clinician from attempting to maintain func- tional walking through a home-based exercise pro- gram and a brief course of goal-directed therapy to improve the gait pattern, strengthen leg muscles, or recondition a patient to lessen disability. A home- based program might include sets of practice in sit-to-stand, supine and prone leg lifts, partial squats while braced against a wall, pool exercise, treadmill walking, specified goals for progressive gains in walk- ing distance or walking speed, modest resistance exercises with weights or latex bands, and practice walking on uneven surfaces and stairs.