Effect of robotic tilt table verticalization on recovery in patients with disorders of consciousness: a randomized controlled trial

Abstract

Verticalization is a common therapeutic intervention during rehabilitation of patients with disorders of consciousness (DoC). The Erigo®Pro is a robotic tilt-table (RTT) with built-in stepping unit for the lower extremities to prevent orthostatic hypotension during verticalization. In addition, the system also provides functional electrical stimulation (FES) of muscles of the lower extremities. In this randomized controlled clinical trial (RCT), 47 patients with subacute DoC received a 4-week verticalization regime (16 verticalization sessions) and were allocated to one of three experimental groups: (1) verticalization by means of RTT with FES, (2) by means of RTT without FES, or (3) by conventional physiotherapy (CPT). Level of consciousness (LoC), spasticity, functional independence in daily activities, and functional brain connectivity measured by means of high-density quantitative EEG were assessed at baseline, directly after the verticalization program and after 6 months. There was a similar clinical improvement in all three experimental groups. RTT was not associated with an effect on any of the clinical outcomes. Verticalization or mobilization time during the study period was significantly positively correlated with recovery of consciousness (rho = 0.494, p < 0.001) in the short term and showed a statistical trend at the 6 months follow-up (rho = 0.244, p = 0.078). In conclusion, RTT treatment is not more effective in promoting recovery of consciousness than CPT in subacute DoC patients. Yet, our data suggest, that verticalization may be an important and feasible rehabilitation intervention in this group of patients. ClinicalTrials.gov NCT Number NCT02639481, registered on December 24, 2015.

Keywords: Disorders of consciousness; ERIGO®; Functional recovery; Tilt table; Verticalization.

Fig. 1

Erigo®Pro (Hocoma AG, Volketswil, Switzerland) robotic tilt table system with cyclic leg movement function with a) 75° and b) 90° tilt, respectively

Fig. 2

CONSORT-guidelines based flow of patients through the study. RTT+F Erigo®Pro treatment with functional electrical stimulation, RTT-F Erigo®Pro treatment without functional electrical stimulation, CPT conventional physiotherapy, T3 time-point after 2 weeks of treatment, T4 time-point of treatment finalization four weeks after inclusion, T5 time-point after treatment follow-up

Fig. 3

Number of patients for whom the level of consciousness (LoC) had (not) increased from baseline (T0) to end of treatment (T4) by at least one category as determined by the Coma Recovery Scale-Revised (CRS-R). Change of category can be unresponsive wakefulness (UWS) to minimally conscious state minus (MCS-), MCS- to minimally conscious state plus (MCS+), or MCS + to emergence from minimally conscious state (eMCS). RTT+F Erigo®Pro treatment with functional electrical stimulation, RTT-F Erigo®Pro treatment without functional electrical stimulation, CPT conventional physiotherapy

Fig. 4

Change scores in spasticity as measured with the Modified Ashworth Scale (MAS) between baseline (T0) and end of treatment (T4). The rectangles represent the interquartile range; the bold horizontal lines inside the rectangles show the medians of each group, empty circles indicate potential outliers whereas the whiskers, which represent 1.5 distance from IQR1 and IQR3, are calculated by the default boxplot R function. RTT+F Erigo®Pro treatment with functional electrical stimulation, RTT-F Erigo®Pro treatment without functional electrical stimulation, CPT conventional physiotherapy

Fig. 5

Correlation between verticalization time (minutes) during the four-week treatment period and the change in the Coma Recovery Scale-Revised (CRS-R) modified score between baseline and end of treatment. RTT+F/−F = robotic tilt table groups with (+F) and without (−F) functional electrical stimulation of the lower limbs. CPT conventional physiotherapy