Wearable sensor and smartphone assisted vestibular physical therapy for multiple sclerosis: usability and outcomes

Abstract

Introduction: Vertigo, dizziness, gaze instability and disequilibrium are highly prevalent in people with MS (PwMS) and head movement induced dizziness is commonly reported. Vestibular physical therapy (VPT) is a specialised, non-invasive and effective therapy for these problems but usually involves travel for the person to a specialist center with both personal and carbon costs. The use of wearable sensors to track head movement and smartphone applications to deliver and track programs has potential to improve VPT in MS.

Methods: This study investigated the usability and effects of a commercially available digital VPT system (wearable head sensor, smartphone app and clinician software) to deliver VPT to PwMS. A pre/post treatment design was employed and the primary outcome was the System Usability Scale (SUS). Other patient reported outcomes were the Service User Acceptability Questionnaire (SUTAQ), the Patient Enablement Instrument (PEI) and the Dizziness Handicap Inventory (DHI). Physical outcomes measurements included Mini-BESTest (MB), Modified Dynamic Gait Index (mDGI), Gait Speed (GS), Dynamic Visual Acuity (DVA) and head kinematics and symptoms during exercise.

Results: Sixteen PwMS (14 female), mean age 44(±14) years were recruited to the study and twelve completed VPT. Mean adherence to exercise, measured digitally was 60% (±18.4). SUS scores were high at 81 (±14) and SUTAQ scores also demonstrated high levels of satisfaction and acceptability of the system. Statistically significant improvements in MB (mean change 2.25; p = 0.004), mDGI (median change 1.00; p = 0.008), DVA (median change -1.00; p = 0.004) were found. Head frequencies significantly improved with concurrent decreased intensity of dizziness during head movements (mean change across 4 gaze stabilization exercises was 23 beats per minute; p < 0.05). Non-significant improvements were seen in DHI (p = 0.07) and GS (p = 0.15). 64.5% of follow up visits were conducted remotely (video or phone), facilitated by the system.

Discussion: This study had two main outcomes and benefits for PwMS. Firstly, we showed that the system used was both acceptable and could be used by PwMS. Secondly, we demonstrated an improvement in a range of dizziness, balance and gait metrics with remotely delivered care. This system has the potential to positively impact on MS physiotherapy service provision with the potential to deliver effective remote care.

Keywords: disequilibrium; dizziness; multiple sclerosis; remote monitoring; vestibular rehabilitation.

Figure 1

The Vertigenius™ system. Participants downloaded the application to their smartphone, which connected to the sensor which was worn behind the ear. (A) The clinician used the clinician software to prescribe, adjust and monitor exercise. (B) The head sensor information collected during exercise at home was relayed to the clinician portal and presented graphically to show whether the gaze stability exercise was performed, performed at the correct frequency in beats per minute (BPM) and dizziness symptoms before and after the exercise (not shown).

Figure 2

System usability scores (SUS) by participant. The SUS is scored out of 100 with higher scores representing higher usability of a given system. A cut-off of 70 (denoted by the dotted line) is the cut-off score for usability.

Figure 3

Service user acceptability technology questionnaire (SUTAQ) subscale scores. The subscales, named in the legend above had a max score of 6. The Privacy and Discomfort, Care Personnel concerns and Kit as Substitution scales are shown below the x axis as high values on these scores reflect high levels of agreement with negative aspects of the “kit”.

Figure 4

Change in dizziness numerical rating scores (out of 10) before and after the four gaze stability exercises both at time 1 and time 2. Time 1 is the first program prescribed and Time 2 is the last program prescribed. On the left It can be seen that for all exercises, the symptoms were higher at T1 than at T2. At both T1 and T2 pre and post exercise scores did not increase significantly. On the right, graphs showing the change in prescribed frequency of head movements at T1 and T2. Participants significantly increased the frequency at which they performed the exercises from T1 to T2 with concurrent decrease in symptoms. *p < 0.05. VORx1 Vestibular ocular reflex times one exercise, NRS Numerical Rating Scale, T1 Time one, T2 Time 2, BPM Beats per minute (frequency at which the participant was performing the exercise with real time feedback of performance via the head sensor and app).