Subjective Visual Vertical Perception Relates to Balance in Acute Stroke

Bonan IV, Guettard E, Leman MC, Colle FM, Yelnik AP. Subjective visual vertical perception relates to balance in acute stroke.

Objective

To determine whether misperception of the subjective visual vertical (SVV) underlies balance difficulties in hemiplegic patients.

Design

Descriptive study, using a convenience sample.

Setting

Department of physical medicine of a university hospital.

Participants

Thirty inpatients with hemiplegia after a hemispheric stroke during the 3 previous months.

Interventions

Not applicable.

Main Outcome Measures

The SVV was tested while subjects sat in a dark room and were asked to adjust a luminous line to the vertical position. Mean SVV deviation and uncertainty, defined as the standard deviation, were calculated for 8 trials. Balance was assessed by the Postural Assessment Scale for Stroke (PASS) and while patients sat on a laterally rocking platform placed on a Satel force platform. The mean body position and the instability score (Lx), calculated as the length of the course of the center of pressure, were recorded. Functional outcome was also evaluated by the FIM instrument.

Results

An abnormal SVV was recorded for 20 of 30 patients. Balance (ie, PASS, Lx) and FIM correlated significantly with SVV tilt (P<.001, P=.01, and P<.001, respectively) and with uncertainty (PASS, P=.006; FIM, P=.003).

Conclusions

Verticality misperception was related to poor balance and might be an important element in the assessment of contributing factors to balance disorders after stroke. It should probably be taken into account when establishing balance rehabilitation programs for patients with hemiplegia.