Use of the Children’s Hospital of Philadelphia Infant Test of Neuromuscular Disorders (CHOP INTEND) in X-Linked Myotubular Myopathy: Content Validity and Psychometric Performance

X-linked myotubular myopathy (XLMTM) is a life-threatening, congenital myopathy characterized by extreme hypotonia, weakness, delayed motor milestones, and respiratory failure, often resulting in pediatric mortality. This study evaluated the content validity and psychometric performance of the Children’s Hospital of Philadelphia Infant Test of Neuromuscular Disorders as a measure of neuromuscular functioning in children with X-linked myotubular myopathy. This study was conducted in two phases. Phase I assessed the content validity of the measure for use in an XLMTM pediatric population through: literature review, clinical expert interviews, caregiver interviews, and a modified-Delphi panel among clinicians. Phase II assessed psychometric performance based on the INCEPTUS observational clinical study and the ASPIRO interventional gene therapy study, including tests of reliability (internal consistency, test-retest, and interrater), validity (construct and criterion), and responsiveness based on observational and interventional clinical trial data analyses. Data established construct validity and reliability of the Children’s Hospital of Philadelphia Infant Test of Neuromuscular Disorders among XLMTM patients before administration of resamirigene bilparvovec, and sensitivity to study drug administration as evidenced by the significant post-administration response in ASPIRO. Findings support the Children’s Hospital of Philadelphia Infant Test of Neuromuscular Disorders as an appropriate neuromuscular functioning assessment in a pediatric X-linked myotubular myopathy patient population.

Effects of SAQ Training and Small-Sided Games on Neuromuscular Functioning in Untrained Subjects

Purpose:The main objective of this study was to investigate the efficacy of both programmed (speed, agility, and quickness; SAQ) and random (small-sided games; SSG) conditioning methods on selected neuromuscular and physical performance variables.Methods:Twenty volunteers (21.1 ± 4.0 y, 1.71 ± 0.09 m, 66.7 ± 9.9 kg; mean ± SD) completed the study. The study design used two physically challenging periodized experimental conditions (SAQ and SSG conditions) and a non exercise control condition (CON). Participants engaged in 12.2 ± 2.1 h of directed physical conditioning. All participants had at least 24 h of recovery between conditioning sessions, and each 1-h session included 15 min of general warm-up and a 45-min exercise session. Participants completed a battery of tests (15-m sprint, isokinetic flexion/extension, depth jump) before and following the training program.Results:There was a 6.9% (95% CI: -4.4 to 18.3) greater improvement in 5-m acceleration time and 4.3% (95% CI: -0.9 to 9.5) in 15-m mean running velocity time for the SAQ group compared with the SSG group. In addition, increases in maximal isokinetic concentric strength for both the flexor and extensor muscles, with the exception of 180 °/s flexion, were greater in the SAQ than SSG condition. The SAQ group also showed 19.5% (95% CI: -11.2 to 50.2) greater gain in reactive strength (contact time depth jump) and 53.8% (95% CI: 11.2 to 98.6) in mean gastrocnemius medialis activity in comparison with SSG.Conclusions:SAQ training should benefit the physical conditioning programs of novice players performing invasion games.

Neuromechanical interaction in human snoring and upper airway obstruction

The fact that snoring and obstructive apnea only occur during sleep means that effective neuromuscular functioning of the upper airway during sleep is vital for the maintenance of unimpeded breathing. Recent clinical studies in humans have obtained evidence demonstrating that upper airway neural receptors sense the negative pressure generated by inspiration and “trigger,” with a certain delay, reflex muscle activation to sustain the airway that might otherwise collapse. These findings have enabled us to propose a model in which the mechanics is coupled to the neuromuscular physiology through the generation of reflex wall stiffening proportional to the retarded fluid pressure. Preliminary results on this model exhibit three kinds of behavior typical of unimpeded breathing, snoring, and obstructive sleep apnea, respectively. We suggest that the increased latency of the reflex muscle activation in sleep, together with the reduced strength of the reflex, have important clinical consequences.

Effects of Occupational Exposure to Inorganic Lead on Neuromuscular Functioning

In an investigation of the behavioral effects of Occupational Exposure to lead, nineteen measures of neuromuscular performance and five measures of the body burden of lead were obtained from 316 experimental and 112 control subjects. The experimental subjects were volunteers from among workers exposed to inorganic lead at their jobs in three storage (lead-acid) battery manufacturing companies; the controls were volunteers from companies involved in other various types of light manufacturing. The relationships among the measures of neuromuscular functioning and body burden of lead were determined through the use of correlation and multiple-regression analyses. The results of these analyses suggest that functional capacity decreased in terms of tremor and eye-hand coordination but increased in terms of muscular strength. In addition, the data suggest that these changes occur on the preferred side and at blood-lead levels between 70 and 79 micrograms per cent.