Reliability of a modified mini balance evaluation systems test (Mini-BESTest) in NF2-related schwannomatosis

OBJECTIVE: To evaluate the reliability and validity of a modified Mini Balance Evaluation Systems Test (Mini-BESTest) in patients with NF2- related schwannomatosis (NF2-SWN). DESIGN: Repeated-measures design. SETTING: Neuro-oncology outpatient clinic. PARTICIPANTS: Individuals with NF2-SWN and clinician-confirmed balance impairment were recruited during outpatient clinic visits. All participants were ambulatory and cognitively capable of providing informed consent. MAIN OUTCOME MEASURES: Reliability was assessed using intraclass correlation coefficients (ICC) for inter-rater and intra-rater performance across two administrations of the Mini-BESTest (scored 0 - 28, higher scores indicating better balance). Concurrent validity was evaluated using the patient-reported Activity-specific Balance Confidence scale (ABC-scale) score collected at first visit (rated 0 - 100%, scores categorized: low 80% confidence maintaining balance during daily activities). RESULTS: Twenty individuals with NF2-SWN (mean age, 48.1 years, 65% male, 60% deafened or hard of hearing) were enrolled. The Mini-BESTest demonstrated excellent inter-rater reliability (ICC = 0.99, CI = 0.97 - 0.995) and intra-rater reliability (ICC = 0.95 and 0.96, CI=0.796 - 0.988 and 0.655 - 0.983 for raters 1 and 2 respectively). Mean Mini-BESTest scores at the first visit were 19.4 and 19.3 across raters (range 6 - 27). The mean ABC score was 74.1% (range, 6.9% - 98.8%). Concurrent validity of the Mini-BESTest with the ABC scale was strong (Spearman p = 0.79 and 0.8 for raters 1 and 2, p < .0001). CONCLUSIONS: The Mini-BESTest shows strong reliability and concurrent validity in NF2-SWN. Its successful administration in deafened or hard of hearing individuals supports its clinical applicability in this population.