Against the odds: what to expect in rehabilitation of chronic spinal cord injury with a neurologically controlled Hybrid Assistive Limb exoskeleton. A subgroup analysis of 55 patients according to age and lesion level

Abstract

<jats:sec><jats:title>Objective</jats:title><jats:p>Age and lesion level are believed to represent outcome predictors in rehabilitation of patients with chronic spinal cord injury (SCI). The Hybrid Assistive Limb (HAL) exoskeleton enables patients to perform a voluntary controlled gait pattern via an electromyography-triggered neuromuscular feedback system, and has been introduced as a temporary gait training tool in patients with SCI. The aim of this prospective pre- and postintervention study was to examine functional outcomes as a function of age and lesion level in patients with chronic incomplete SCI (iSCI) or chronic complete SCI (cSCI) with zones of partial preservation (ZPP) by using the HAL as a temporary training tool.</jats:p></jats:sec><jats:sec><jats:title>Methods</jats:title><jats:p>Fifty-five participants with chronic iSCI or cSCI (mean time since injury 6.85 ± 5.12 years) were classified according to the American Spinal Injury Association (ASIA) Impairment Scale (AIS) and divided by age (&lt; 50 or ≥ 50 years), independent of lesion level, and also into 4 homogeneous groups according to lesion level. The subgroups were as follows: Subgroup 1, tetraplegic iSCI (n = 13) (C2–8, AIS C [n = 8] and AIS D [n = 5]); Subgroup 2, paraplegic iSCI with spastic motor behavior (n = 15) (T2–12, AIS C [n = 8] and AIS D [n = 7]); Subgroup 3, paraplegic cSCI with complete motor paraplegia and absence of spastic motor behavior (n = 18) (T11–L4 [AIS A], and ZPP from L-3 to S-1); and Subgroup 4, paraplegic iSCI with absence of spastic motor behavior (n = 9) (T12–L3, AIS C [n = 8] and AIS D [n = 1]). The training paradigm consisted of 12 weeks of HAL-assisted treadmill training (5 times/week). Baseline status was documented prior to intervention by using the AIS grade, Walking Index for SCI II (WISCI II) score, the 10-meter walk test (10MWT), and the 6-minute walk test (6MinWT). Training effects were assessed after 6 and 12 weeks of therapy, without HAL assistance.</jats:p></jats:sec><jats:sec><jats:title>Results</jats:title><jats:p>Overall, a time reduction of 47% in the 10MWT, self-selected speed (10MWTsss) (&lt; 50 years = 56% vs ≥ 50 years = 37%) and an increase of 50% in the 6MinWT were documented. The WISCI II scores showed a mean gain of 1.69 levels. At the end of the study, 24 of 55 patients (43.6%) were less dependent on walking aids. Age had a nonsignificant negative influence on the 10MWTsss. Despite a few nonsignificant subgroup differences, participants improved across all tests. Namely, patients with iSCI who had spastic motor behavior improved to a nonsignificant, lesser extent in the 6MinWT.</jats:p></jats:sec><jats:sec><jats:title>Conclusions</jats:title><jats:p>The HAL-assisted treadmill training leads to functional improvements in chronic iSCI or cSCI, both in and out of the exoskeleton. An improvement of approximately 50% in the 10MWTsss and in gait endurance (6MinWT) can be expected from such training. The influences of SCI lesion level and age on functional outcome were nonsignificant in the present study. Older age (≥ 50 years) may be associated with smaller improvements in the 10MWTsss. An iSCI in paraplegic patients with spastic motor behavior may be a nonsignificant negative predictor in gait endurance improvements.</jats:p><jats:p>Clinical trial registration no.: DRKS00010250 (<jats:ext-link xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="uri" xlink:href="https://drks-neu.uniklinik-freiburg.de/drks_web/setLocale_DE.do">https://drks-neu.uniklinik-freiburg.de/drks_web/setLocale_DE.do</jats:ext-link>)</jats:p></jats:sec>

Motor Adaptation to Weight Shifting Assistance Transfers to Overground Walking in People with Spinal Cord Injury

“…Although the age of participants ranged from 24 to 66 years, the majority of participants in this study (71%) were ≥ 50 years old. In addition, previous studies showed mixed results about the impact of participant age (ie, ≥ 50 vs < 50 years) on achieving the walking function in people with SCI . Thus, we believe that the variability in age of participants might not have a systematic impact on our results.…”

“…In addition, previous studies showed mixed results about the impact of participant age (ie, ≥ 50 vs < 50 years) on achieving the walking function in people with SCI. 35,36 Thus, we believe that the variability in age of participants might not have a systematic impact on our results. Participants with tetraplegia and participants with paraplegia may show differences in response to the pelvis assistance force because people with tetraplegia who have various degrees of arm paralysis are often less capable of using arms to compensate the pelvis assistance force than people with paraplegia who have normal arm functions.…”

Functional Neurorehabilitation using the Hybrid Assistive Limb (HAL): A First Experience in the United States

“…Although evidence is only beginning to emerge in the literature, the effectiveness of bodyweight supported treadmill training with HAL ® in patients with spinal cord injuries and neurologic disorders has been analyzed and suggests promising results [13,[21][22][23].…”

“…Furthermore, these studies have shown that training with HAL ® improves quality of life, decreases neuropathic pain and increases patient's functional mobility, over-ground walking, muscle strength and motor function in and out of HAL ® [11][12][13][14].…”

Editorial. The next generation of powered exoskeleton use in spinal cord injury

“…3 This represents the latest generation in assistive mechanical exoskeletons, whereby neurological feedback drives exoskeleton use. The aim of this study was to examine functional outcomes with regard to rehabilitation in patients with chronic SCI, adding valuable prospective clinical data to the limited body of literature.…”