Using Subthreshold Vibratory Stimulation During Poststroke Rehabilitation Therapy: A Case Series

Abstract

Subthreshold vibratory stimulation to the paretic wrist has been shown to prime the sensorimotor cortex and improve 2-week upper extremity (UE) therapy outcomes. The objective of this work was to determine feasibility, safety, and preliminary efficacy of the stimulation over a typical 6-week therapy duration. Four chronic stroke survivors received stimulation during 6-week therapy. Feasibility/safety/efficacy were assessed at baseline, posttherapy, and 1-month follow-up. For feasibility, all participants wore the device throughout therapy and perceived the stimulation comfortable/safe. Regarding safety, no serious/moderate intervention-related adverse events occurred. For efficacy, all participants improved in Wolf Motor Function Test and UE use in daily living based on accelerometry and stroke impact scale. Mean improvements at posttherapy/follow-up were greater than the minimal detectable change/clinically important difference and other trials with similar therapy without stimulation. In conclusion, the stimulation was feasible/safe for 6-week use. Preliminary efficacy encourages a larger trial to further evaluate the stimulation as a therapy adjunct.

Keywords: paresis; patient safety; physical stimulation; stroke rehabilitation; subliminal stimulation; upper extremity.

Figure 1.

The stimulation device (circled) was worn on the paretic wrist and delivered subthreshold vibration during task-practice therapy addressing upper extremity motor function, such as the ability to use a screwdriver.

Figure 2.

Mean and individual scores on the Wolf Motor Function Test time (A), Box and Block Test (B), hours of paretic upper extremity use per day measured by the accelerometer (C) and Stroke Impact Scale - Hand (D) and Activities of Daily Living (ADL) subscales (E). Darker lines represent the mean and lighter lines represent individual participant scores.

Figure 3.

Week-to-week change in the Wolf Motor Function Test (WMFT) time (A) and hours of paretic upper extremity use per day measured by the accelerometer (B). The mean and standard error of the changes are shown. The Minimum Detectable Change (MDC) for WMFT (Lin et al., 2009) is also shown (A).

Figure 4.

Comparison to other trials. (A) Change in the Wolf Motor Function Test time compared to other large trials with similar manual therapy of 10 (Winstein et al., 2016) and 12 (Lo et al., 2010) weeks. The mean and standard error (SE) of the change are shown. Minimum detectable change (MDC) (Lin et al., 2009) is also shown. Changes in the Stroke Impact Scale - Hand (B) and Activities of Daily Living (ADL) subscales (C) are compared to other trials with similar manual therapy of 6 (Birkenmeier et al., 2010) and 8 (Lang et al., 2016) weeks. The mean and SE of the change score are shown for the present study. The mean change and SE of the raw score are shown for other trials because SE of the change was not provided. Minimum detectable change (MDC) (Lin et al., 2010) and minimal clinically important difference (MCID) (Lin et al., 2010) are also shown.