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105. Motor unit number estimating evaluations in spinobulbar muscular atrophy
American Association of Neuromuscular & Electrodiagnostic Medicine / Clinical Neurophysiology 119 (2008) e27–e65
Methods: There were 112 patients with ALS enrolled. Semiautomatic incremental stimulation was applied for MUNE. The compound muscle action potential (CMAP) amplitude, total Medical Research Council (MRC) manual muscle testing score, ALS-functional rating score (ALS-FRS), Appel’s ALS score (AALSS), and forced vital capacity (FVC) were also recorded. Results: MUNE was modestly correlated with muscle strength score (P < 0.01), highly correlated with CMAP amplitude (P < 0.01). Both MUNE and CMAP amplitude correlated with ALS-FRS (Ps < 0.05) and AALSS (Ps < 0.01) significantly. A MUNE decrease was observed at month 3, 6, and 12 compared with baseline. The rate of change at month 3 was 50.5%. Mean CMAP amplitude, ALS-FRS, total MRC score, and FVC declined sharply or smoothly. The decrease in MUNE over the first 3 months was significantly greater than other measurements. Conclusions: MUNE measurement is suited to provide insight into the natural history of the disease process and may be useful to follow progression and response in drug trials. MUNE and CMAP amplitude may help to stratify patients based on their progression rate, which could enable the results to be more coincident for each subgroup in future clinical trials in ALS. doi:10.1016/j.clinph.2007.11.153
104. Trapezius motor unit number estimation by decomposition-spike triggered average—S.G. Sheth, R.A. Lewis (Detroit, MI, USA) Introduction: Motor unit number estimation (MUNE) has been used to assess the degree of motor unit loss in a number of disorders including amyotrophic lateral sclerosis (ALS), Charcot–Marie–Tooth disease (CMT) and spinal muscular atrophy (SMA). Only a few techniques lend themselves to studies of proximal muscles. Biceps brachii MUNE can be difficult and cannot be utilized in most clinical trials. The trapezius has C2-4 innervation overlapping with the innervation of the diaphragm. Objectives: To report preliminary results of the application of decomposition-spike triggered averaging (De-STA) to the trapezius and to show that this may be an optimal muscle to study in these disorders. Methods: De-STA MUNE was performed on normal controls and patients with ALS and CMT. The details of the technique will be described. Normal values will be determined based on the studies of control subjects. The results of patients with ALS and CMT will be compared to the control values. Results: To date, 3 controls, 3 CMT, and 1 ALS patient have been studied but we will report a significantly larger cohort as the study is ongoing. The control MUNE values were 251, 271, and 289; CMT MUNEs were 116, 195, and 239; ALS MUNE was 159. Conclusions: This study shows that a trapezius MUNE can be obtained by De-STA. MUNE values may be lower in patients than in controls. Trapezius MUNE has a number of advantages over biceps MUNE and may be particularly informative in ALS as trapezius motor unit loss may be an excellent marker of respiratory and bulbar dysfunction. Dr. Lewis is a consultant for Talecris Biotherapeutics. doi:10.1016/j.clinph.2007.11.154
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105. Motor unit number estimating evaluations in spinobulbar muscular atrophy—C. Chen 1, N. DiProspero 2, K. Fischbeck 2, M. Floeter 2, T.J. Lehky 2 (1 Baltimore, MD, USA, 2 Bethesda, MD, USA) Introduction: Spinobulbar muscular atrophy (SBMA) or Kennedy’s disease is an x-linked neuronopathy associated with progressive loss of motor and sensory neurons. Motor unit number estimating (MUNE) should be useful in evaluating progression in SBMA. In amyotrophic lateral sclerosis (ALS) clinical trials, Shefner and colleagues has proposed modifying the statistical MUNE to account for greater single motor unit potential (SMUP) variability in ALS by excluding SMUPs <40 lV. It is unknown whether this modification is applicable to the more chronic degenerative disease of SBMA. Objective: To evaluate the different methodologies for calculating the statistical MUNE in SBMA patients. Methods: Statistical MUNE was performed on one hand muscle, usually the abductor pollicis brevis, in 53 SBMA patients. The MUNE was calculated using number-weighted method and accounting for high- amplitude single motor units. The standard parameter of excluding SMUP <10 lV was compared with the exclusion of SMUP <40 lV. Results: The mean statistical MUNE, using the standard method and the Shefner modification, was 59.38 ± 21.51 and 45.65 ± 23.26, respectively, with a concordance of 0.49 (two-sided 95% CL for qv = 0.31, p > 0.0001). Similar to ALS, SBMA showed a higher mean SMUP (275.15 lV) because of the presence of high-amplitude SMUPs and an increased proportion (17%) of individual SMUPs 40 lV compared to normals. Conclusions: Statistical MUNE calculations using the Shefner modifications may be more appropriate for SBMA patients because of their similar SMUP characteristics to ALS. The resultant MUNE is lower than the MUNE obtained from the standard method. doi:10.1016/j.clinph.2007.11.155
106. The prevalence of myasthenia gravis auto-antibodies in patients with amyotrophic lateral sclerosis—V. Taghavi, E.J. Sorenson (Rochester, MN, USA) Introduction: An autoimmune basis for amyotrophic lateral sclerosis (ALS) has long been proposed but remains controversial. A number of auto-antibodies have been reported in ALS. We have explored the immune reaction occurring at the motor endplate in ALS by studying the prevalence of auto-antibodies of muscle end-plate antigens. Objective: To determine the prevalence of muscle acetylcholine receptor antibodies in ALS. Method: We retrospectively reviewed records of consecutive ALS patients with testing for autoimmune myasthenia gravis over a 4-year time period. We reviewed and compared patient demographics between those with to those without acetylcholine receptor antibodies. Results: Seventy-four ALS patients tested for muscle membrane auto-antibodies were identified. AChR binding antibodies were found in 4 and striational antibodies in one additional patient, for a prevalence rate of 6.7%. Seropositive patients were
Methods: There were 112 patients with ALS enrolled. Semiautomatic incremental stimulation was applied for MUNE. The compound muscle action potential (CMAP) amplitude, total Medical Research Council (MRC) manual muscle testing score, ALS-functional rating score (ALS-FRS), Appel’s ALS score (AALSS), and forced vital capacity (FVC) were also recorded. Results: MUNE was modestly correlated with muscle strength score (P < 0.01), highly correlated with CMAP amplitude (P < 0.01). Both MUNE and CMAP amplitude correlated with ALS-FRS (Ps < 0.05) and AALSS (Ps < 0.01) significantly. A MUNE decrease was observed at month 3, 6, and 12 compared with baseline. The rate of change at month 3 was 50.5%. Mean CMAP amplitude, ALS-FRS, total MRC score, and FVC declined sharply or smoothly. The decrease in MUNE over the first 3 months was significantly greater than other measurements. Conclusions: MUNE measurement is suited to provide insight into the natural history of the disease process and may be useful to follow progression and response in drug trials. MUNE and CMAP amplitude may help to stratify patients based on their progression rate, which could enable the results to be more coincident for each subgroup in future clinical trials in ALS. doi:10.1016/j.clinph.2007.11.153
104. Trapezius motor unit number estimation by decomposition-spike triggered average—S.G. Sheth, R.A. Lewis (Detroit, MI, USA) Introduction: Motor unit number estimation (MUNE) has been used to assess the degree of motor unit loss in a number of disorders including amyotrophic lateral sclerosis (ALS), Charcot–Marie–Tooth disease (CMT) and spinal muscular atrophy (SMA). Only a few techniques lend themselves to studies of proximal muscles. Biceps brachii MUNE can be difficult and cannot be utilized in most clinical trials. The trapezius has C2-4 innervation overlapping with the innervation of the diaphragm. Objectives: To report preliminary results of the application of decomposition-spike triggered averaging (De-STA) to the trapezius and to show that this may be an optimal muscle to study in these disorders. Methods: De-STA MUNE was performed on normal controls and patients with ALS and CMT. The details of the technique will be described. Normal values will be determined based on the studies of control subjects. The results of patients with ALS and CMT will be compared to the control values. Results: To date, 3 controls, 3 CMT, and 1 ALS patient have been studied but we will report a significantly larger cohort as the study is ongoing. The control MUNE values were 251, 271, and 289; CMT MUNEs were 116, 195, and 239; ALS MUNE was 159. Conclusions: This study shows that a trapezius MUNE can be obtained by De-STA. MUNE values may be lower in patients than in controls. Trapezius MUNE has a number of advantages over biceps MUNE and may be particularly informative in ALS as trapezius motor unit loss may be an excellent marker of respiratory and bulbar dysfunction. Dr. Lewis is a consultant for Talecris Biotherapeutics. doi:10.1016/j.clinph.2007.11.154
e59
105. Motor unit number estimating evaluations in spinobulbar muscular atrophy—C. Chen 1, N. DiProspero 2, K. Fischbeck 2, M. Floeter 2, T.J. Lehky 2 (1 Baltimore, MD, USA, 2 Bethesda, MD, USA) Introduction: Spinobulbar muscular atrophy (SBMA) or Kennedy’s disease is an x-linked neuronopathy associated with progressive loss of motor and sensory neurons. Motor unit number estimating (MUNE) should be useful in evaluating progression in SBMA. In amyotrophic lateral sclerosis (ALS) clinical trials, Shefner and colleagues has proposed modifying the statistical MUNE to account for greater single motor unit potential (SMUP) variability in ALS by excluding SMUPs <40 lV. It is unknown whether this modification is applicable to the more chronic degenerative disease of SBMA. Objective: To evaluate the different methodologies for calculating the statistical MUNE in SBMA patients. Methods: Statistical MUNE was performed on one hand muscle, usually the abductor pollicis brevis, in 53 SBMA patients. The MUNE was calculated using number-weighted method and accounting for high- amplitude single motor units. The standard parameter of excluding SMUP <10 lV was compared with the exclusion of SMUP <40 lV. Results: The mean statistical MUNE, using the standard method and the Shefner modification, was 59.38 ± 21.51 and 45.65 ± 23.26, respectively, with a concordance of 0.49 (two-sided 95% CL for qv = 0.31, p > 0.0001). Similar to ALS, SBMA showed a higher mean SMUP (275.15 lV) because of the presence of high-amplitude SMUPs and an increased proportion (17%) of individual SMUPs 40 lV compared to normals. Conclusions: Statistical MUNE calculations using the Shefner modifications may be more appropriate for SBMA patients because of their similar SMUP characteristics to ALS. The resultant MUNE is lower than the MUNE obtained from the standard method. doi:10.1016/j.clinph.2007.11.155
106. The prevalence of myasthenia gravis auto-antibodies in patients with amyotrophic lateral sclerosis—V. Taghavi, E.J. Sorenson (Rochester, MN, USA) Introduction: An autoimmune basis for amyotrophic lateral sclerosis (ALS) has long been proposed but remains controversial. A number of auto-antibodies have been reported in ALS. We have explored the immune reaction occurring at the motor endplate in ALS by studying the prevalence of auto-antibodies of muscle end-plate antigens. Objective: To determine the prevalence of muscle acetylcholine receptor antibodies in ALS. Method: We retrospectively reviewed records of consecutive ALS patients with testing for autoimmune myasthenia gravis over a 4-year time period. We reviewed and compared patient demographics between those with to those without acetylcholine receptor antibodies. Results: Seventy-four ALS patients tested for muscle membrane auto-antibodies were identified. AChR binding antibodies were found in 4 and striational antibodies in one additional patient, for a prevalence rate of 6.7%. Seropositive patients were