Motor Unit Action Potential Analysis Research Articles

Peak-ratio interference pattern analysis in the detection of neuromuscular disorders

Peak-ratio interference pattern analysis (peak-ratio method) is said to have a high sensitivity and to be independent of sex and age. This study was carried out to prove or disprove these findings. The peak-ratio method and qualitative motor unit action potential (MUAP) analysis were applied to the right brachial biceps and anterior tibial muscles of 44 healthy subjects, aged 23–87 years, 25 neuropathy patients, aged 21–83 years, and 29 myopathy patients, aged 19–70 years. Peak-ratio parameters were independent of sex and age. They tended to be lower in the anterior tibial muscle than in the brachial biceps muscle. Neuropathy patients typically showed decreased peak-ratio, short time intervals and increased amplitude/turn. Myopathy patients typically showed increased peak-ratio, turns/s and short time intervals. The sensitivity of the peak-ratio method was 72% for neuropathy patients and 59% for myopathy patients. The sensitivity of the peak-ratio method was similar to that of the MUAP analysis in neuropathy patients and higher than that of the MUAP analysis in myopathy patients. The specificity of the peak-ratio method was 80%. The peak-ratio method proved to be a valuable, supplementary electromyographic tool for the detection of neuromuscular disorders.

Needle EMG of the tongue: motor unit action potential versus peak ratio analysis in limb and bulbar onset amyotrophic lateral sclerosis

OBJECTIVESto find out if conventional and automatic needle EMG of the tongue can be helpful in the diagnosis and differentiation of limb and bulbar onset amyotrophic lateral sclerosis.METHODSMotor unit action...

Comparison of reliability of different algorithms used for quantitative computer assisted motor unit action potential analysis

Comparison of reliability of different algorithms used for quantitative computer assisted motor unit action potential analysis

Automatisierte quantitative EMG-Untersuchung: Analyseverfahren, Probleme der Referenzwertbestimmung und klinischer Stellenwert

The current state of the motor unit action potential (MUAP) analysis is reviewed. New quantitative analysis methods, like template matching and multi-MUAP analysis are described and compared with traditional manual techniques. Emphasis is put also on the physiological basis, definition, and clinical relevance of various old and new MUAP parameters like duration, amplitude, area, thickness (area/amplitude), size index, number of phases and turns. Various problems of building up reference values are discussed. To increase the diagnostic sensitivity of quantitative EMG analysis the detection of individual outlyers is described. Traditional as well as new indications of the technique of quantitative EMG analysis will be given.

Quantitative motor unit action potential analysis in paraspinal muscles

Quantitative motor unit action potential analysis in paraspinal muscles

Quantitative motor unit action potential analysis in paraspinal muscles.

Quantitative motor unit action potential analysis in paraspinal muscles.

Manual of Nerve Conduction Velocity and Clinical Neurophysiology

Part 1 Introduction: basic nerve conduction studies - general information techniques - general considerations technical procedures troubleshooting temperature effects on nerve conduction velocities and latencies other variability in nerve conduction velocities and common sources of error. Part 2 Cranial nerves: facial nerve distal motor latency to the nasalis muscle orbicularis oris facial nerve distal motor latency to the orbicularis oris hypoglossal motor nerve conduction latency. Part 3 Cervical plexus: greater nerve conduction spinal accessory nerve motor latency phrenic nerve motor. Part 4 Upper extremity nerves: long thoracic nerve motor latency dorsal scapular nerve motor latency suprascapular nerve motor latency to supraspinatus and infraspinatus axilliary nerve motor latency to the deltoid musculocutaneous motor latency to the biceps brachii musculocutaneous sensory latency and nerve conduction velocity radial motor nerve conduction velocity radial motor nerve conduction to extensor digitorum communis radial nerve distal sensory latency anterior interosseous nerve motor latency to the pronator quadratus median motor nerve conduction velocity and latency median nerve distal sensory latency median nerve sensory conduction - short segment stimulation at the wrist median orthodromic and antidromic studies C-8 and T-1 nerve root stimulation electrodiagnostic values through the thoracic outlet using C-8 root studies, F waves and cervical somatosensory evoked potential ulnar motor nerve conduction velocity ulnar nerve motor conduction latency to the first dorsal interosseous muscle ulnar nerve motor conduction across the elbow - short segment stimulation ulnar nerve distal sensory latency dorsal cutaneous ulnar nerve conduction medial antebrachial cutaneous nerve conduction and latency. Part 5 Intercostal nerve motor latency: intercostal nerve distal latency and conduction velocity. Part 6 Lower extremity nerves. Part 7 Reflex, wave and long latency. Part 8 Motor nerve conduction velocity studies in premature infants, infants and children. Part 9 Repetitive stimulation. Part 10 Somatosensory evoked potentials. Part 11 Movement-related potentials. Part 12 Intraoperative monitoring using somatosensory evoked potentials. Part 13 Auditory and visual evoked potentials. Part 14 Magnetoelectric stimulation. Part 15 Motor unit action potential analysis. Part 16 Single fibre electromyography. Part 17 Anatomy. Appendix.

Quantitative motor unit action potential analysis in paraspinal muscles

Quantitative motor unit action potential analysis in paraspinal muscles

Multi‐motor unit action potential analysis (MMA)

We have developed an algorithm, called multi-motor unit action potential analysis (MMA), to aid quantification in routine needle EMG examination. In only 5-8 min, it was possible to extract, analyze, and validate 20 motor unit action potentials (MUAPs). In the biceps muscle of normal subjects, the MUAP measurements are compared with measurements using manual, triggered averaging, automatic decomposition, and other MMA algorithms described in the literature. The mean values of MUAP features by MMA fell between the extreme limits obtained from the amplitude-triggered method and the manual method described in the literature. In patients, the results are consistent with routine EMG and similar to those results described in the literature. Fast acquisition and analysis of MUAPs as well as interference pattern (IP) analysis make this technique useful to document EMG abnormalities in routine needle examination.

Turns‐amplitude analysis of the electromyographic recruitment pattern disregarding force measurement. II. Findings in patients with neuromuscular disorders

Turns-amplitude analysis of the electromyographic recruitment pattern was performed on-line in the brachial biceps muscle of 46 patients with neuromuscular disorders using the mean amplitude as an indicator of force. The parameters, peak-ratio (PR) and number of time intervals (TI) from 0 to 1.5 ms, were increased in patients with myopathy. In patients with neurogenic involvement, the characteristic pattern was a decreased PR and a decreased incidence of TI between 0 and 1.5 ms. The results indicate that the two parameters supplement each other as some of the patients were identified only by one or the other. In patients with myopathy, the method had a higher diagnostic yield than the individual motor unit action potential analysis. The method is objective, fast, and reliable.

Quantitative EMG in inflammatory myopathy

Fifty-four quantitative electromyographic (EMG) studies were made in 37 patients with inflammatory myopathy (IM) at different points in their clinical course and treatment. All studies were performed in the biceps brachii which varied in clinical strength. Motor unit action potentials (MUAPs) in 45 studies and EMG interference pattern (IP) in 48 studies were recorded using a concentric needle electrode. Macroelectromyographic (Macro-EMG) MUAPs were recorded from 10 patients in 14 studies. MUAP analysis revealed a myopathic pattern (decreased duration and/or area: amplitude ratio) in 69% of studies. IP analysis was more sensitive than MUAP analysis, demonstrating a myopathic pattern in 83% of studies. Macro-EMG MUAP amplitudes were reduced in two studies, minimally increased in one study and normal in the remainder; in 6 (40%) studies, fiber density was slightly increased. Thus, reinnervation does not seem to play an important role in motor unit remodeling in IM.

Long‐duration polyphasic motor unit potentials in myopathies: A quantitative study with pathological correlation

In most myopathies, the duration of motor unit action potentials (MUAPs) is shorter than normal. However, polyphasic MUAPs of duration longer than 20% of the control mean, (long-duration polyphasic potentials, or LDPPs) may be seen. We therefore analyzed the incidence and meaning of LDPPs using quantitative MUAP analysis in 41 patients with different myopathies. The mean duration of all potentials was reduced in only 64% of patients because LDPPs increased the mean. When only simple potentials were considered, however, the mean duration was decreased in 95% of patients. This observation confirms the need to exclude LDPPs when calculating the mean duration of MUAPs for diagnosis. We found LDPPs most often in chronic polymyositis and in one patient with Becker Muscular Dystrophy. LDPPs are attributed to desynchronization of single-fiber potentials within the MUAP and may be due to slow conduction in regenerating muscle fibers.

Evaluation of an automatic method of measuring features of motor unit action potentials

This study was performed to evaluate an automatic method of motor unit action potential (MUAP) analysis developed in our laboratory. MUAPs were recorded from the biceps brachii muscle of 68 normal subjects and 122 patients with nerve or muscle disease. The values of mean MUAP durations from normal subjects obtained by automatic analysis were similar to those reported in the literature. However, the normal range of MUAP amplitude and the incidence of polyphasic MUAPs were much higher. Normal ranges of mean MUAP area, area/amplitude ratio, and the number of turns were also defined. Automatic analysis demonstrated an abnormality of at least one MUAP feature in 70% of patients. There was concordance between automated analysis and visual assessment of MUAPs in 76% of patients with neuropathy but in only 50% of patients with myopathy. The relationships between different MUAP features seen in neuropathy and myopathy are explained in physiologic terms.

Automatic decomposition electromyography (ADEMG): validation and normative data in brachial biceps

We describe a new, automatic method (ADEMG) for decomposing EMG interference patterns into their constituent motor unit action potentials (MUAPs), and quantitating the configurational and firing properties of the MUAPs. ADEMG is fast (90 sec analysis time for a 10 sec EMG epoch) and efficient (33–98% of MUAP occurences correctly identified) because of 4 signal-processing innovations designated digital prefiltering, high-resolution wave from alignment, firing-time analysis and interference-cancellation averaging. Validation experiments are described involving recruitment/derecruitment of low-threshold MUAPs, and single-fiber-triggered averaging. Normative data are presented for 2000 MUAPs from brachial biceps (mean 9.7 MUAPs per site) at 3 levels of isometric contraction (7%, 15% and 30% MVC) and contrasted with normal findings obtained using traditional, low-threshold MUAP analysis. The main advantages of ADEMG are (1) speed of data acquisition and processing in the clinical setting; (2) ability to analyze both low-and high-threshold MUAPs during moderately strong muscular contractions; and (3) MUAP firing-rate information.