Romberg test: Differentiating vestibular from somatosensory ataxia

The Romberg Test (RT) is a traditional bedside test of static balance. However, its nonspecific original description and focus on proprioceptive deficits have limited its diagnostic utility for vestibular dysfunction. We used gyroscopic measurements of trunk sway at the body's center of mass, time to fall, and a Subjective Instability score (SI) to gain more detailed insights than the binary outcomes typically used in clinical practice.

To evaluate whether specific patterns of sway and sway perception during the RT and its variants differentiate individuals with vestibular and proprioceptive deficits from healthy controls (HC).

We assessed 18 patients with chronic imbalance, divided into three groups: unilateral vestibular loss, bilateral vestibular loss, and isolated sensory predominant peripheral neuropathy (SPPN). Six healthy individuals served as HCs. All participants underwent clinical history, physical examination, and ancillary nerve conduction and vestibular tests when appropriate. Each performed eight stance tasks with simultaneous SI scoring and trunk sway recording.

Trunk sway for eyes closed on foam was significantly greater in vestibulopathy than in neuropathy patients (p < 0.05). Conversely, SPPN patients showed greater imbalance on firm ground (eyes closed) than on foam. SPPN patients also had the greatest mismatch between objective and subjective instability on firm ground. Tandem tasks were less useful for group differentiation. No correlation was found between fall direction and the more hypofunctioning vestibulo-ocular reflex (VOR) side in vestibular patients.

The main distinguishing feature between vestibular and somatosensory ataxia across tasks are the differing sway patterns between firm and foam surfaces.