Introduction
Vestibular dysfunctions have diverse aetiologies and are commonly associated with dizziness and vertigo, affecting 1.4 per cent of the global population and up to 30 per cent of individuals in their lifetime.Reference Castro, Teles, Lima, Fontenele, Bastos and Teixeira1–Reference Parker, Hartel, Paratz, Choy and Rahmann3 These symptoms can stem from vestibular, cardiovascular, neurological or psychological origins,Reference Parker, Hartel, Paratz, Choy and Rahmann3, Reference Suvanich, Chatchawan, Jariengprasert, Yimtae, Hunsawong and Emasithi4 making accurate diagnosis essential.
In 24–43 per cent of cases, vertigo originates from benign peripheral causes such as benign paroxysmal positional vertigo (BPPV) or vestibular neuritis, although serious central disorders must be ruled out.Reference Castro, Teles, Lima, Fontenele, Bastos and Teixeira1, Reference Vanni, Pecci, Casati, Moroni, Risso and Nazerian2 Anamnesis is critical: in up to 80 per cent of cases, the underlying cause is revealed during history-taking.Reference Parker, Hartel, Paratz, Choy and Rahmann3
Vestibular physiotherapy is a recognised area of physiotherapy practice in Brazil.Reference Zuma e, Ramos, Mangabeira Albernaz, Cal and Schubert5, 6 Accurate classification is essential to define effective treatment strategies, which may include exercises, manoeuvres, electrotherapy and assistive devices.
Despite increased publication of diagnostic criteria for conditions like BPPV,Reference Von Brevern, Bertholon, Brandt, Fife, Imai and Nuti7 vestibular migraine,Reference Lempert, Olesen, Furman, Waterston, Seemungal and Carey8–Reference Staab, Eckhardt-Henn, Horii, Jacob, Strupp and Brandt10 and Ménière’s disease,Reference Lopez-Escamez, Carey, Chung, Goebel, Magnusson and Mandalà11 physiotherapists face difficulty integrating this knowledge into structured clinical reasoning. Clinical tools like the HINTS examinationReference Warner, Bunn, Koohi, Schmidtmann, Freeman and Kaski12–Reference Elias and Longen14 and video-oculography aid diagnosis, but decision-making in physiotherapy still lacks standardised support.Reference Pasquali15–Reference Fantino, Allali, Muir, Montero-Odasso and Annweiler20
The Subgroup Classification System for Low Back PainReference Reichenheim, Moraes, Minayo and Deslandes16 inspired the creation of a similar structure for vestibular dysfunctions. Teixeira (2020, verbal communication) proposed the Subgroup Classification System for Vestibular Dysfunctions to support physiotherapists in clinical decision-making.
This study aimed to validate the Subgroup Classification System for Vestibular Dysfunctions and answer the question: does the Subgroup Classification System for Vestibular Dysfunctions have content validity and support clinical decision-making in vestibular physiotherapy?
Method
An observational study was conducted to validate the Subgroup Classification System for Vestibular Dysfunctions. Eligible participants were physiotherapists specialising in vestibular rehabilitation. The study was approved by the Ethics Committee of the Faculty of Medicine of Marília (CAAE: 69132823.2.0000.5413).
Following Pasquali’s framework,Reference Silva and Montilha17 the study involved theoretical, empirical and analytical stages. The validation occurred in four steps: (1) development of the tool and review by five expert physiotherapists; (2) incorporation of suggested modifications; (3) application to 15 physiotherapists using simulated cases; and (4) data analysis and final tool revision.
Content validation used the Delphi technique,Reference Lynn18 involving two rounds. Judges rated each item using a Likert scale and Content Validity Index of 0.78 or more was considered acceptable.Reference Lynn18 Sample groups were based on years of experience: less than 2 years, between 3 and 6 years, and more than 7 years.
Clinical cases were designed to reflect common vestibular dysfunctions. Each participant answered questions using the Subgroup Classification System for Vestibular Dysfunctions. Utility was rated on a Likert scale.
The structure of the Subgroup Classification System for Vestibular Dysfunctions is presented in Figure 1. The six initial content validation questions and their responses by the five expert judges are shown in Table 1. Adjustments based on the first round were incorporated, and the second-round results are shown in Table 2.
Structure of the Subgroup Classification System for Vestibular Dysfunctions.
First stage of judgment by five physical therapists on the flowchart
IN = inadequate; NA = needs adjustment; AD = adequate; IVCitem = Content Validity Index per item
Source: Own elaboration
Second stage of the evaluation by the five physical therapists on the flowchart
IN = inadequate; NA = needs adjustment; AD = adequate; IVCitem = Content Validity Index per item
Results
Five expert judges participated in the Delphi rounds, with professional experience ranging from 11 to 25 years. In the first round, Content Validity Index scores were 0.78 or more for all items (Table 1). Based on feedback, some diagnostic categories were reassigned, such as mal de débarquement and presbyvestibulopathy.
In the second round, all items achieved 100 per cent agreement (Content Validity Index = 1.0), confirming content validity (Table 2).
Fifteen physiotherapists then applied the Subgroup Classification System for Vestibular Dysfunctions to 10 simulated cases. Accuracy improved with experience: Group 1 scored 76 per cent, Group 2 scored 91 per cent and Group 3 scored 95 per cent (Table 3).
Accuracy rate of the 15 physiotherapists in clinical cases by experience time
Utility ratings showed that 80 per cent of participants in all groups ‘completely agreed’ that the tool was helpful (Table 4).
Agreement rate of the 15 physiotherapists on the utility of the flowchart
Description of vestibular dysfunction subgroups
Note: The Subgroup Classification System comprises nine vestibular dysfunction subgroup.
Discussion
The Subgroup Classification System for Vestibular Dysfunctions demonstrated strong content validity and was well-received by physiotherapists. Higher experience correlated with better case accuracy, highlighting the importance of clinical exposure.
Few tools exist to assist vestibular classification in physiotherapy. The Subgroup Classification System for Vestibular Dysfunctions addresses this gap by offering a structured framework aligned with validated clinical syndromes.Reference Castro, Teles, Lima, Fontenele, Bastos and Teixeira1, Reference Von Brevern, Bertholon, Brandt, Fife, Imai and Nuti7–Reference Lopez-Escamez, Carey, Chung, Goebel, Magnusson and Mandalà11
Limitations include lack of a control group, the use of online application and a relatively small sample. Future studies should assess reliability and effectiveness in real-world clinical practice.
An instructional video and flowchart are available at Zenodo (Figure 1; DOI: 10.5281/zenodo.10401256).
• Diagnosing vestibular dysfunctions is challenging because of symptom variability and comorbidities, and physiotherapists lack standardised classification tools to guide decision-making
• This study presents the development and validation of the first validated subgroup classification tool designed to assist physiotherapists in vestibular rehabilitation
• The tool was applied by physiotherapists to simulated clinical cases and assessed by expert consensus
• The tool achieved strong content validity and unanimous expert agreement, supporting clinical use in clinical decision-making for vestibular physiotherapy
Conclusion
The Subgroup Classification System for Vestibular Dysfunctions was validated for content and showed promising utility in clinical decision-making. Further studies are recommended to expand its use and validate its impact in broader clinical settings.
Acknowledgements
This work was supported by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior – Brazil (CAPES), Finance Code 001.
Competing interests
None declared.
