EFFECT OF KINESTHETIC ILLUSION INDUCED BY VISUAL STIMULATION ON SUBACUTE STROKE PATIENTS USING AN ABAB STUDY DESIGN

M. Okawada^1,2, I. Toru³, S. Motozawa³, N. Matsuda⁴, E. Shibata⁵, M. Yoneta^1,2, S. Sasaki^1,2, F. Kaneko¹

Background: Kinesthetic illusion induced by visual stimulation (KINVIS) induces a vivid kinesthetic sensation without voluntary movement. Single-arm clinical studies of KINVIS in chronic stroke patients with severe paralysis have shown potential improvements in motor function and spasticity. As an underlying mechanism of such clinical effects, KINVIS may act on the motor output system. Motor output reorganization after stroke involves increased corticospinal excitability by stimulation of the remaining corticospinal tract in the acute phase and increased intercortical excitability of new networks and reorganization of the cortical network in the subacute phase. Considering these differences, based on the time from stroke onset, it is estimated that KINVIS will be more effective in early to subacute stages than in the chronic stage. Therefore, we explored the effect of KINVIS on motor function improvement in subacute stroke patients using control conditions and considering the severity of paralysis.

Purpose: To examine the intervention effect of KINVIS on motor function in subacute stroke patients.

Methods: Ten stroke patients (right hemiparesis; 5 patients, age; 55.4±16.2 years, time from the onset; 59.6±15.7) participated. The study was performed using an ABAB design (A1, B1, A2, B2; 10 days for each period). In periods A1 and A2, 60 minutes of task-oriented upper limb functional training was added to conventional rehabilitation. In periods B1 and B2, KINVIS targeting finger flexion and extension movements was applied for two sessions, 10 minutes each, for a total of 20 minutes in addition to the interventions of periods A1 and A2. The Action Research Arm Test (ARAT) was performed before A1 and after each period to evaluate upper limb motor function. Based on ARAT scores, patients were classified into mild (3 patients), moderate (4 patients), and severe (3 patients) groups. The gradient and variation method were used in the visual analysis. In the former, the slope of the regression line of ARAT scores before and after each period, and in the latter, the coefficient of variation of ARAT before and after each period was calculated.

Results: In the gradient method, the result of all groups was 0.45/0.41/ 0.15/0.25 (A1/B1/A2/B2). In the mild group the result was 0.33/0.03/-0.1/0.07, in the moderate group 0.53/0.98/ 0.35/0.65, and in the severe group 0.47/0.03/0.13/-0.1. In the variation method, the result of all groups was 20.6/20.0/19.6/20.1. The mild group was 3.5/1.2/1.9/2.0, the moderate group was 3.3/5.5/4.1/5.9, the severe group was 3.3/3.6/4.6/4.8.

Conclusion(s): The slope and coefficient of variation of the ARAT regression line were higher in B1 and B2 than A1 and A2 in the moderate group. Thus, in future clinical trials it is important to consider KINVIS indication with reference to the severity of motor paralysis.

Implications: KINVIS improves motor function of the paralyzed limb despite being an intervention that does not require the patient's voluntary effort. Application of KINVIS in cases likely to benefit from the intervention will contribute in improving future physical therapy practices.

Funding, acknowledgements: This work was supported by AMED (Grant Number JP16he0402255h0003, JP19192664), and JSPS KAKENHI (Grant Number JP19H01088).

Keywords: KINVIS, subacute stroke, ABAB design

Topic: Neurology: stroke

Did this work require ethics approval? Yes

Institution: Asahikawa Rehabilitation Hospital

Committee: Asahikawa Rehabilitation Hospital Ethics Committee

Ethics number: B-018