The INVEST trial: a randomised feasibility trial of psychologically informed vestibular rehabilitation versus current gold standard physiotherapy for people with Persistent Postural Perceptual Dizziness
David Herdman, Sam Norton, Louisa Murdin, Kate Frost, Marousa Pavlou, Rona Moss‐Morris
Abstract
Abstract Background Persistent postural perceptual dizziness (PPPD) is a common and disabling functional neuro-vestibular disorder. We aimed to determine the feasibility and acceptability of conducting a randomised controlled trial of cognitive-behavioural therapy informed vestibular rehabilitation (INVEST intervention) designed for persistent dizziness. Methods A two-armed parallel groups randomised feasibility study of INVEST vs. a time-matched gold standard vestibular rehabilitation (VRT) control. Participants with PPPD were recruited from a specialist vestibular clinic in London, UK. Participants were individually randomised using a minimisation procedure with allocation concealment. Measures of feasibility and clinical outcome were collected and assessed at 4 months. Results Forty adults with PPPD were randomised to six sessions of INVEST ( n = 20) or gold standard VRT ( n = 20). Overall, 59% of patients screened met the inclusion criteria, of which 80% enrolled. Acceptability of INVEST, as assessed against the theoretical framework of acceptability (TFA), was excellent and 80% adhered to all 6 sessions. There were small to moderate treatment effects in favour of INVEST across all measures, including dizziness handicap, negative illness perceptions, symptom focussing, fear avoidance, and distress (standardised mean difference [SMD] g = 0.45; SMD g = 0.77; SMD g = 0.56; SMD g = 0.50, respectively). No intervention-related serious adverse events were reported. Conclusions The study results give strong support for the feasibility of a full-scale trial. Both arms had high rates of recruitment, retention, and acceptability. There was promising support of the benefits of integrated cognitive-behavioural therapy-based vestibular rehabilitation compared to gold standard vestibular rehabilitation. The study fulfilled all the a-priori criteria to advance to a full-scale efficacy trial. Trial registration number ISRCTN10420559.