Wearable sensors help measure motor changes during SBMA progression
Study: Future studies must address technical challenges with devices
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- Wearable sensors objectively measured motor changes in SBMA patients during clinical tests.
- Sensor data correlates with standard functional measures, offering insights into individual SMA progression.
- Challenges, such as data loss, need to be addressed ahead of routine use.
Using wearable sensors during clinical tests may help doctors objectively measure changes in movement ability for people with spinal bulbar muscular atrophy (SBMA), a study reports.
“These findings support incorporating wearable sensors into clinic assessments and encourage future work using home-based monitoring in larger SBMA cohorts,” researchers wrote.
Despite this potential, the team also noted limitations to current sensor technology. A major challenge was data loss due to faulty sensors or constraints in the clinical environment. Before integrating sensors into routine evaluations of people with SBMA, future studies will need to address some of these problems, researchers wrote.
The study, “Using wearable sensors during the timed up and go and 6-minute walk test in Spinal Bulbar Muscular Atrophy,” was published in PLOS Digital Health.
Need exists for more accurate motor outcome measures
SBMA is a rare form of spinal muscular atrophy (SMA). People with the most common SMA types typically begin experiencing symptoms of muscle weakness and wasting in infancy, childhood, or adolescence. SBMA symptoms often emerge in adulthood, and the disease tends to progress slowly.
Currently, clinicians use a variety of motor tests to track the progressive loss of movement abilities. However, results can vary depending on the test conditions and other factors.
“There is a need for reliable, valid, and accurate motor outcome measures to support the development of clinical trials in SBMA,” the researchers wrote.
Wearable sensors may provide a way to objectively assess subtle changes in movement direction, speed, and acceleration in SBMA.
In the present study, the team tested a sensor-based system with 10 participants with SMBA. All of them were men, with a mean age of 62.2. During clinical exams, participants performed a Timed Up and Go (TUG) test and a Six-Minute Walk Test (6MWT), two standard clinical evaluations of motor function.
Each participant completed the exams three times at six-month intervals, for a total of one year of data collection. They wore sensors on their wrists, ankles, chest, and lower back.
TUG measures how quickly an individual can stand from a chair, walk about 10 feet, turn around, walk back to the chair, and sit back down. This helps clinicians get an overall sense of a patient’s mobility during normal activities.
“Overall, TUG performance remained relatively stable over the three time periods,” the researchers noted. As a group, the participants didn’t tend to get slower, suggesting their motor function didn’t decline notably during the year. Sensor data showed that participants who turned more quickly also completed the test more quickly. This relationship remained unchanged over the year.
6-minute walking test scores were relatively stable
During the 6MWT, clinicians measure the distance that an individual can walk in six minutes. This is often used as a metric of exercise capacity.
As with TUG, mean 6MWT performance was similar across the three time points. Participants who took more steps per minute, spent less time per step, and covered more distance per step traveled farther.
While 6MWT scores were relatively stable, individual participants’ results varied more. Some participants improved, walking farther with each assessment. Others showed a substantial degree of decline over the year.
“These findings highlight that group-level [statistics] may obscure clinically meaningful changes in small, rare disease cohorts, and that individual-level data and effect sizes provide more informative assessment of disease progression,” the researchers wrote.
Overall, the results showed that the gait and balance parameters captured with sensors correlated strongly with standard functional measures, and that a score of difficulties with activities of daily living correlated with the 6MWT.
“The sensors are easy to initialize during clinic visits, quick to place on the participant, not burdensome to the participant, and do not affect performance,” the team wrote. “However, substantial technical challenges remain before these tools are ready for routine clinical implementation.”
Major concerns that emerged during the study were data loss due to sensor issues, constraints in the exam environment, and analytical challenges.
“Critically, future work must prioritize improving technical reliability and reducing missing data rates to make these sensors viable for clinical trials and remote monitoring in SBMA,” the researchers noted.
Other limitations of the study included a relatively small number of participants and a relatively short follow-up period. SBMA’s slow progression means that one year may not have been long enough to capture important changes in movement across participants.
