Wearable robotic device may boost walking ability for SMA patients
Study found people who were also taking Spinraza saw improvement
Training with a wearable robotic device called HAL, for hybrid assistive limb, improved walking ability for people with spinal muscular atrophy (SMA) who were also receiving treatment with Spinraza (nusinersen), according to a study in Japan.
“[These] results may provide sufficient data to inform clinical decision-making about the potential addition of cybernic treatment with HAL to treat patients with SMA, while simultaneously receiving [Spinraza] and standard individual-based physiotherapy,” the researchers wrote.
The study, “Enhancing the effects of nusinersen with cybernic treatment using Hybrid Assistive Limb (HAL) in spinal muscular atrophy: a real-world case series and exploratory cohort analysis,” was published in the Orphanet Journal of Rare Diseases.
SMA is mainly caused by mutations in the SMN1 gene that result in little or no production of the survival motor neuron protein (SMN), which is important for the survival and function of motor neurons, the nerve cells that control voluntary movements. This results in the progressive loss of these neurons and SMA symptoms like muscle weakness and wasting.
Scientists in Japan developed HAL together with the robotics company Cyberdyne. The technology captures the signals the brain sends to the muscles for initiating movement through sensors in the skin, which then assist the patient in moving. It was shown to improve walking abilities in people with spinal and bulbar muscular atrophy, a type of adult-onset SMA.
Robotic device safety, efficacy assessed in patients taking DMTs
For the study, researchers analyzed the safety and efficacy of a combination of HAL and Spinraza, a disease-modifying therapy, in people with SMA who were also receiving physiotherapy.
The study involved 12 patients, six children and six adults, of whom eight had SMA type 3 and four SMA type 2. Seven of the patients were male. All were treated with Spinraza and conventional physiotherapy; five also received HAL. The HAL group was older (mean age 36) than the group not using the device (mean age 24.6).
HLA sessions consisted of walking exercises for 20-30 minutes, recommended over nine sessions at least twice weekly, during which a hoist was used as a body weight support to prevent falls. After 15 months, these participants had received a mean of 42.8 HLA sessions, spaced by a mean of 12.8 days.
Although most patients experienced motor function improvement, as measured by the Hammersmith Functional Motor Scale-Expanded, the proportion of those who experienced a clinically meaningful improvement (an increase of 3 or more points) was higher in the HAL group (80% vs. 42.9%). Taking into account age, SMA type, time from disease onset to Spinraza initiation, and time from Spinraza to HAL, the difference (4.7 points on the scale vs. 2.9 points) between the groups was not statically significant.
There was a clinically important improvement in the Revised Upper Limb Module (RULM) score in patients who also underwent HAL sessions. No such improvement was seen in those who did not, because three patients already had the maximum RULM score at study start.
Similar effects were seen for the two-minute walking test, used to assess walk endurance by measuring the distance patients can walk for two minutes. In this measure, participants who underwent HAL experienced improvements, but the difference between the groups was not statistically significant.
Patients who used HAL also experienced increases in walking speed and step length, although no significant differences were seen relative to the controls.
“This approach may hold promise for other SMA therapies that aim to increase SMN protein levels,” the researchers wrote. “However, while the study provided promising results, it does not establish the superiority of HAL therapy over other rehabilitation approaches.”
The authors said their study had limitations, including the small number of participants.
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