This study describes skeletal, neuromuscular and fitness impairments among 109 children (median age 10 (range 4–18) years, 65.1% male, 63.3% white) with acute lymphoblastic leukemia (ALL), enrolled on a physical activity trial from 2009 to 2013. Outcomes were measured 7-10 days after diagnosis and compared to age- and sex-specific expected values. Associations between function and HRQL were evaluated with logistic regression. Children low values for BMD z-scores/height (mean±standard error: −0.53±0.16 vs. 0.00±0.14, p <0.01), body mass index percentile (57.6±3.15 vs. 50.0±3.27%, p=0.02), quadriceps strength (201.9±8.3 vs. 236.1±5.4 Newtons, p<0.01), six minute walk distance (385.0±13.1 vs. 628.2±7.1 meters, p < 0.001), and Bruininks-Oseretsky Test of Motor Proficiency (23±2.5 vs. 50±3.4%, p < 0.001). Quadriceps weakness was associated with a 20.9-fold (95% CI 2.5–173.3) increase in poor physical HRQL. Children with newly diagnosed ALL have weakness and poor endurance and may benefit from early rehabilitation that includes strengthening and aerobic conditioning.

Background: Motor unit number index (MUNIX) is a validated electrophysiological biomarker in amyotrophic lateral sclerosis. MUNIX studies in spinal muscular atrophy (SMA) are limited. Methods: Later-onset SMA children (n = 13; three SMN2 copy number) were evaluated for Hammersmith Motor Function Scale Expanded (HMFSE) and MUNIX of right abductor pollicis brevis (APB) and abductor digiti minimi (ADM) muscles. Agematched healthy controls (n = 8) were enrolled to obtain normative APB and ADM MUNIX values. Results: Mean APB and ADM MUNIX values in SMA subjects were significantly reduced (P < .001) compared with controls. HMFSE scores strongly correlated with ADM MUNIX (r 0.63). Conclusions: APB and ADM muscle MUNIX studies are feasible in SMA type 2 children. ADM MUNIX correlated with disease severity on motor function testing.

No abstract