China Dizziness and Vertigo Cohort Study （VERIDICAL STUDY）

This study is designed as a prospective, multicenter, real-world observational registry based on the Chinese Headache and Vertigo Registry System (CHRS), aiming to systematically characterize the etiological spectrum, diagnostic evolution, and clinical outcomes of patients presenting with dizziness and/or vertigo across neurology and otolaryngology outpatient settings in China. Participants will be consecutively or randomly enrolled from approximately 69 hospitals across more than 30 provinces, and all clinical data will be collected using standardized electronic case report forms within the CHRS platform. The registry integrates structured baseline assessments, including demographic characteristics, detailed clinical history, neurological and otological examinations, and standardized vestibular and audiological investigations, as well as validated patient-reported outcome measures. Etiological classification will be performed according to the Bárány Society International Classification of Vestibular Disorders consensus criteria, with supplementary classification based on ICD-11 when necessary. Longitudinal follow-up will be conducted at predefined time points up to 12 months, with extended follow-up allowed when clinically indicated, to evaluate diagnostic stability, symptom evolution, treatment response, and functional outcomes under routine clinical practice.

A comprehensive data management and quality assurance framework will be implemented. The CHRS registry will incorporate predefined data validation rules, including range checks, logical consistency checks, and cross-variable verification to ensure internal data integrity. Source data verification will be performed through periodic comparison of registry entries with medical records, imaging reports, and original clinical documentation at participating sites. A detailed data dictionary will be maintained, defining each variable, coding standards (including internationally recognized terminologies where applicable), and measurement scales. Standard Operating Procedures (SOPs) will govern all aspects of registry operations, including patient recruitment, informed consent, data entry, follow-up procedures, adverse event reporting, data monitoring, and protocol amendments. Site monitoring and auditing will be conducted periodically by independent reviewers to ensure protocol adherence and data accuracy.

Missing data will be managed according to predefined rules, including documentation of missingness mechanisms (e.g., unavailable, non-reported, or out-of-range values), and handled using appropriate statistical techniques such as multiple imputation or sensitivity analyses when applicable. Sample size determination is based on expected prevalence estimates and study precision requirements, with planned enrollment of approximately 6,000 participants to ensure adequate statistical power and representativeness. A detailed statistical analysis plan will be implemented, specifying descriptive analyses, comparative analyses, longitudinal modeling, and regression-based approaches to address primary and secondary objectives. All analyses will be conducted using validated statistical software, and results will be reported in accordance with relevant guidelines for observational registry studies.

Inclusion criteria

• Participants must meet all of the following criteria:a) Age between 18 and 65 years, inclusive;b) Male or female;c) Consecutive patients presenting to dizziness/vertigo outpatient clinics in the Departments of Neurology or Otolaryngology at 69 hospitals across more than 30 provinces in China, with symptoms of spatial orientation impairment or balance disturbance, including vertigo, dizziness, vestibular-visual symptoms, and postural symptoms;d) Ability and willingness to provide written informed consent

Exclusion criteria

• Inability to cooperate with essential diagnostic procedures, including medical history collection, physical examination, laboratory investigations, or other required evaluations, resulting in failure to establish a basic clinical diagnosis;b) Refusal or inability to provide written informed consent.