Persistent Dizziness and Time-Domain Dissociation in Vestibular Function: A Hypothesis-Generating Case Series and...

Background/Objectives: Persistent dizziness after the apparent resolution of an acute or episodic vestibular disorder remains a frequent and clinically challenging condition. In many patients, symptoms persist despite negative positional testing, absence of spontaneous nystagmus, and preserved high-frequency vestibular responses on video head impulse testing. This discrepancy suggests that persistent dizziness may not always be explained by incomplete recovery of a single peripheral vestibular lesion but may reflect a dissociation between transient/high-frequency vestibular responses and sustained/low-frequency or integrative vestibular processing. The aim of this study was to propose a hypothesis-generating, case-based clinical framework for interpreting this dissociation and its implications for targeted vestibular rehabilitation. Methods: This was a retrospective, hypothesis-generating, case-based clinical study derived from routine specialist neuro-otological practice. Four illustrative cases were selected because they represented distinct patterns of persistent dizziness in which preserved or near-preserved transient vestibular responses coexisted with abnormalities in sustained, otolithic, visual-vestibular, or velocity-storage-dependent processing. All patients underwent detailed clinical history assessment, bedside neuro-otological examination, and multidomain vestibular assessment according to clinical indication. The purpose of the study was not to estimate prevalence, validate diagnostic accuracy, or demonstrate treatment efficacy but to illustrate a physiology-based interpretive framework. Results: The four cases showed different patterns of time-domain dissociation. These included low-frequency integrative dysfunction without clear peripheral lateralization, incompletely compensated unilateral vestibular asymmetry, selective unilateral otolithic loss despite preserved semicircular canal high-frequency responses, and bilateral sustained vestibular hypofunction unmasked by an apparently resolved BPPV-like event. Across cases, persistent symptoms were better explained by the relationship between transient and sustained vestibular domains than by any single test result considered in isolation. Conclusions: Persistent dizziness may arise from different combinations of preserved transient vestibular responses and impaired sustained or integrative vestibular processing. The proposed framework does not introduce new vestibular tests and does not claim to validate a new diagnostic entity. Rather, it organizes established vestibular investigations within a time-domain model that may help identify clinically meaningful dissociations and guide individualized, domain-specific vestibular rehabilitation. Prospective studies with larger samples and external validation are required to determine the diagnostic and therapeutic value of this approach.