Biomedical subjects

D Jillapalli

Publications and source records attributed to D Jillapalli.

3 recordsLinked to original sources

PubMed2007

Revised statistical motor unit number estimation in the Celecoxib/ALS trial.

Techniques to estimate motor unit number (MUNE) measure the number of functioning motor units in a muscle. As amyotrophic lateral sclerosis (ALS) is characterized by progressive motor unit loss, this disease offers an ideal setting for the use of MUNE. Statistical MUNE was employed in a recent multicenter trial of creatine in ALS, and was shown to be reliable, reproducible, and to decline with disease progression. However, motor unit amplitude stayed constant over 7 months, a finding believed to reflect an artifact of the method. The statistical method was revised to reflect more accurately the presence of larger motor units and employed in a 12-month study of Celecoxib in ALS. MUNE declined by 49% in 12 months; however, motor unit amplitude again stayed constant over the same period. Statistical MUNE estimates motor unit number based on the variability of response to a repeated stimulus of constant strength, with an underlying assumption that this variability is due solely to the number of motor units responding in an intermittent manner. Based on studies showing that single motor units in ALS display excessive amplitude variability when stimulated repeatedly, we show that response variability in ALS patients is in large part due to single unit changes. Thus, we conclude that the statistical method is not an appropriate measure of motor unit number in any disease associated with motor unit instability.

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PubMed2004

The use of statistical MUNE in a multicenter clinical trial.

Techniques to estimate motor unit number (MUNE) measure the number of functioning motor units in a muscle. In diseases characterized by progressive motor unit loss, such as amyotrophic lateral sclerosis (ALS), MUNE may be useful to monitor disease progression or beneficial response to treatment. As part of a multicenter, placebo-controlled, randomized, double-blind clinical trial testing the efficacy of creatine in patients with ALS, statistical MUNE was measured in 104 patients tested monthly for 6 months. The objective was to determine whether MUNE was a reliable and sensitive outcome measure in the context of a multicenter trial. Formal training and reliability testing was required for all MUNE evaluators. Testing of normal controls showed a high degree of test-retest reliability. All patient data were combined as the experimental treatment showed no efficacy. There was a 23% decline in MUNE over 6 months. The technique as employed in this trial overemphasized the presence of small motor units; this problem was partially addressed by poststudy data monitoring and censuring. Thus, MUNE can be used reliably as an outcome measure in multicenter clinical trials; specific remedies are suggested for the difficulties encountered in this study.

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PubMed1999

Reducing intersubject variability in motor unit number estimation.

Motor unit number estimation (MUNE) attempts to directly assess the number of functioning motor units present in a muscle. It is an important addition to the electrodiagnostic evaluation; however, both intrasubject and intersubject reliability must be minimized for this technique to be clinically useful. A number of MUNE techniques have been developed. We propose a change in the way of calculating the MUNE, using the statistical technique described by Daube, and show that this modification reduces intersubject variability and improves test-retest reliability in normal subjects.

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