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Over the last decade, motor unit number estimation (MUNE) methods have been applied with increasing frequency to the study of amyotrophic lateral sclerosis. MUNE is the ideal tool for the assessment of diseases in which the primary defect is motor unit loss, as it enables quantitation and tracking of motor unit numbers while simultaneously gauging countervailing collateral reinervation. These properties make it particularly useful for assessing the effects of both neuroprotective therapies and therapies designed to enhance collateral reinervation, not only in animal models but also in the living patient. Previous studies have supplied important natural history information, confirming an average 50% loss of motor units for every six months of disease progression, and newer pathophysiological investigations are providing unique insight into motor unit behavior in the face of progressive anterior horn cell death. More recent efforts have incorporated MUNE into ongoing, multi-center clinical trials as a putative early biomarker, with encouraging results. As MUNE methods continue to be refined and disseminated, they are proving to be useful and unique tools for the study of motor neuron disease.

Objective: To compare characteristics of ALS patients with and without percutaneous endoscopic gastrostomy (PEG)., Methods: Using the ALS Patient Care Database, data from patients with and without PEG with ALS Functional Rating Scale-bulbar subscale (ALSFRSb) scores < or = 5 were analyzed; follow-up data were also collected., Results: PEG use was markedly increased with declining ALSFRSb scores. Demographics did not differ, but ALSFRS composite scores and bulbar and arm subscale scores were lower (P<0.0001). PEG patients used significantly more assistive devices, multidisciplinary care, home care nurses and aides, had more frequent physician and emergency department visits and hospital admissions (P<0.0001), and had lower health status based on the mini-SIP scale (P=0.0047). PEG use varied greatly between ALS centers. In the follow-up study, positive impact of PEG was noted in 79 % of PEG patients but in only 37.5% of patients who received PEG later, based on a small number of patients. PEG use showed no survival benefit., Conclusion: Patients did not receive PEG until bulbar function was severely reduced and overall ALS had markedly progressed. PEG may have been performed too late to demonstrate survival benefits. Aggressive proactive nutritional management appears essential in patients with ALS. To determine whether PEG provides benefits, it must be performed at earlier stages of the disease and prospectively studied.

We present our experience with 27 patients with symptoms of alveolar hypoventilation, a precursor to respiratory failure, to demonstrate variability in symptoms, physiologic status and outcome of intervention. They represent 27 consecutive patients who tolerated NIPPV for more that 4 hours per 24-h period for more than 2 weeks. All patients received neurological consultation, electromyography and met criteria for ALS according to El Escorial diagnostic criteria. To assess respiratory status, spirometry was measured in sitting and when possible, in the supine positions. Resting arterial blood gases were available in 22 patients. Orthopnea was the most common symptom at the time of institution of NIPPV. No correlation existed between age at institution of NIPPV, duration of effective use of this technology or vital capacity and duration of effective use of NIPPV. The lack of correlation between vital capacity at the institution of NIPPV and duration of its effectiveness suggest that more sensitive indicators for the onset of alveolar hypoventilation must be defined, particularly since the principal benefit from its use is relief of symptoms of alveolar hypoventilation.