Characteristics of uncompensated acute unilateral vestibulopathy and preliminary clinical characteristics of patients with direction-changing positional nystagmus: a retrospective observational study

Objectives: Vestibular compensation supports recovery after acute unilateral vestibulopathy (UVP). A subset of patients develops direction-changing positional nystagmus (DCPN), which may reflect atypical central adaptation. The objective was to preliminarily investigate clinical characteristics of UVP patients with persistent vestibular weakness presenting with DCPN.Methods: Seventeen patients with persistent unilateral weakness on video head impulse test (mean 41 days post-onset) were analyzed retrospectively. Three exhibited DCPN (DCNp group) and were compared with 14 without DCPN (CONTROLp group) using vestibular testing and magnetic resonance imaging white matter hyperintensity (WMH) grading.Results: The DCNp group showed reduced spontaneous and head-shaking nystagmus amplitudes (p<0.05) and selectively decreased gains in the contralesional anterior and ipsilesional posterior canals (p<0.05). Periventricular WMH burden was significantly higher in the DCNp group (mean 3.0 vs. 1.8; p=0.001), while deep WMH did not differ.Conclusions: DCPN in UVP is linked to canal-specific gain asymmetry and increased periventricular WMH, suggesting impaired central compensation possibly influenced by cerebrovascular microstructural changes.