This systematic review aimed to investigate the effects of interventions intended for retraining leg somatosensory function on somatosensory impairment, and secondary outcomes of balance and gait, after stroke.
Databases searched from inception to 16 January 2019 included Cochrane Library, PubMed, MEDLINE, CINAHL, EMBASE, PEDro, PsycINFO, and Scopus. Reference lists of relevant publications were also manually searched.
All types of quantitative studies incorporating interventions that intended to improve somatosensory function in the leg post stroke were retrieved. The Quality Assessment Tool for Quantitative Studies was used for quality appraisal. Standardised mean differences were calculated and meta-analyses were performed using preconstructed Microsoft Excel spreadsheets.
The search yielded 16 studies, comprising 430 participants, using a diverse range of interventions. In total, 10 of the included studies were rated weak in quality, 6 were rated moderate, and none was rated strong. Study quality was predominantly affected by high risk of selection bias, lack of blinding, and the use of somatosensory measures that have not been psychometrically evaluated. A significant heterogeneous positive summary effect size (SES) was found for somatosensory outcomes (SES: 0.52; 95% confidence interval (CI): 0.04 to 1.01; I2 = 74.48%), which included joint position sense, light touch, and two-point discrimination. There was also a significant heterogeneous positive SES for Berg Balance Scale scores (SES: 0.62; 95% CI: 0.10 to 1.14; I2 = 59.05%). Gait SES, mainly of gait velocity, was not significant.
Somatosensory impairment is common after stroke, occurring in up to 89% of stroke survivors.1Proprioception and tactile somatosensation are more impaired in the leg than in the arm post stroke,2 with the frequency increasing with increasing level of weakness and stroke severity.2,3 Leg somatosensory impairment also has a significant impact on independence in daily activities3 and activity participation in stroke survivors,4 as well as predicts longer hospital stays and lower frequency of home discharges.5
Leg somatosensory impairment negatively influences balance and gait. Post-stroke plantar tactile deficits correlate with lower balance scores and greater postural sway in standing.6 Tactile and proprioceptive feedback provide critical information about weight borne through the limb.7 Accordingly, tactile and proprioceptive somatosensory deficits may hinder paretic limb load detection ability, potentially leading to reduced weight-bearing and contributing to balance impairment and falls post stroke.8 Indeed, stroke survivors with somatosensory impairment have a higher falls incidence compared to those without somatosensory impairment.3 In addition to reduced balance, impaired load detection may also contribute to gait asymmetry, particularly in the push-off phase.8 In addition, leg proprioception influences variance in stride length, gait velocity,9 and walking endurance in stroke survivors.10 In fact, leg somatosensory impairment has been shown to be the third most important independent factor for reduced gait velocity in stroke survivors.11
Two systematic reviews have previously investigated the effects of interventions for retraining somatosensory function after stroke.12,13 In the first review, published more than a decade ago, only four of the 14 included studies targeted the leg,12 while the second only included studies of the arm.13 Nevertheless, both reviews reported that there were insufficient data to determine the effectiveness of these interventions. A third systematic review evaluating the effectiveness of proprioceptive training14 only included 16 studies with stroke-specific populations, of which only two specifically addressed the leg. From these three reviews, the effects of interventions for post-stroke leg somatosensory impairment remain unclear. In addition, the first review12 was critiqued for including studies with participants without somatosensory impairment, and that did not report somatosensory outcomes.15 Therefore, a targeted systematic review, addressing the limitations of previous reviews, is required to elucidate the effects of interventions for post-stroke leg somatosensory impairment.
It is of interest to clinicians and researchers to evaluate the effects of leg somatosensory retraining on factors that may ultimately influence activity and participation, as this could change practice. Therefore, this systematic review aimed to examine the effects of post-stroke leg somatosensory retraining on somatosensory impairment, balance, gait, motor impairment, and leg function.[…]