Reliability, validity, and usability of an 18-item immersive virtual reality action research arm test: a validation study in stroke survivors.

Motor neuron diseases (MNDs) are a group of rare neurological disorders that selectively affect motor neurons responsible for controlling voluntary muscles []. These conditions impact individuals across all age groups, including children and adults, and although clinical presentations may vary between patients, all MNDs are characterized by movement‐related symptoms, particularly muscle weakness [, ]. The most common MNDs include amyotrophic lateral sclerosis (ALS) and spinal muscular atrophy (SMA). ALS typically manifests after the age of 40–50 years and may arise from genetic or idiopathic causes. It is defined by the degeneration and death of upper motor neurons (connecting the brain to the spinal cord) and lower motor neurons (linking the spinal cord to skeletal muscles). As a progressive disorder, ALS leads to muscle atrophy and weakness in various regions of the body. The disease is ultimately fatal due to respiratory failure caused by the weakness of the diaphragm and chest wall muscles. No cure currently exists for ALS, and available therapies focus on symptom management [, ]. Hereditary ALS accounts for ~10% of cases and is frequently associated with mutations in genes encoding SOD1, C9orf72, or TDP‐43 [, ]. The heterogeneity of neuromuscular diseases (NMDs), coupled with the low prevalence of most conditions, has complicated the identification of underlying etiologies and the development of targeted therapies. Furthermore, treatment options for the majority of these disorders remain limited, often restricted to supportive care that fails to halt disease progression []. Despite significant advancements in recent decades across fields such as genetics, pathophysiology, and cellular‐molecular mechanisms, a critical need persists for effective therapies to address neuromuscular pathologies and motor impairments [, ]. As noted, existing treatments have thus far only delayed the disease progression. Among potential therapeutic strategies explored over the past decade, the concept of tissue regeneration or repair using stem cell‐derived progenitors has gained prominence. Multiple cell types with diverse tissue origins and characteristics, including myogenic stem/progenitor cells, stromal cells, and pluripotent stem cells, have been investigated over the years, with recent clinical trials yielding variable outcomes. Stem cells are indispensable to living organisms, exhibiting two defining properties: self‐renewal and differentiation potential. Based on potency, they are classified into totipotent, pluripotent, multipotent, oligopotent, and unipotent subtypes. Among these, pluripotent stem cells have been extensively utilized for diverse applications []. To date, these stem cells have been employed in clinical trials to assess their safety, efficacy, and therapeutic potential for treating numerous disorders, including Duchenne muscular dystrophy (DMD), SMA, and various neuropathies [–].