Electromyographic Interference Pattern Analysis / The Japanese Journal of Rehabilitation Medicine

Needle electromyography is used to investigate motor unit abnormalities, consisting of the anterior horn cell, the axon, the nerve end-plate, and the associated muscle fibers. The characteristics of the firing and recruitment patterns of motor units during voluntary contraction are identified as an interference pattern that is used clinically for the diagnosis of neuropathy and myopathy. Quantitative analysis of this interference pattern, using such factors as zero-crossing, spike count, number of turns (NT), the peak-to-peak amplitude, mean amplitude (MA), and automatic amplitude of the interference pattern envelope, is used to identify interference patterns resulting from specific pathologies. It is difficult, however, to improve the sensitivity and specificity of the analysis for the diagnosis of neuropathy and myopathy by separately analyzing the number or amplitude of the spikes involved in the interference pattern. Therefore, turn amplitude analysis has been developed, which combines the number and amplitude of the spikes. For the NT:MA ratio and peak ratio analysis (PRA), the turns are examined during a constant voluntary contraction. In contrast, for the cloud analysis, the distribution of NT and MA at various muscle strengths is plotted. Expert Quantitative Interference Pattern Analysis (EQUIP), which applies the expertise of an electromyographer, provides practical sensitivity and specificity for the clinical diagnosis of neuropathic and myopathic diseases. Understanding these various quantitative interference pattern analysis modalities will not only improve the ability of physiatrists to interpret electromyographic findings, but will also expand their knowledge of motor unit diseases.

Electromyographic Interference Pattern Analysis-Various Qualitative and Quantitative Analyses and their Limitations- / The Japanese Journal of Rehabilitation Medicine

Needle electromyography is used to investigate motor unit abnormalities, consisting of the anterior horn cell, the axon, the nerve end-plate, and the associated muscle fibers. The characteristics of the firing and recruitment patterns of motor units during voluntary contraction are identified as an interference pattern that is used clinically for the diagnosis of neuropathy and myopathy. Quantitative analysis of this interference pattern, using such factors as zero-crossing, spike count, number of turns (NT), the peak-to-peak amplitude, mean amplitude (MA), and automatic amplitude of the interference pattern envelope, is used to identify interference patterns resulting from specific pathologies. It is difficult, however, to improve the sensitivity and specificity of the analysis for the diagnosis of neuropathy and myopathy by separately analyzing the number or amplitude of the spikes involved in the interference pattern. Therefore, turn amplitude analysis has been developed, which combines the number and amplitude of the spikes. For the NT:MA ratio and peak ratio analysis (PRA), the turns are examined during a constant voluntary contraction. In contrast, for the cloud analysis, the distribution of NT and MA at various muscle strengths is plotted. Expert Quantitative Interference Pattern Analysis (EQUIP), which applies the expertise of an electromyographer, provides practical sensitivity and specificity for the clinical diagnosis of neuropathic and myopathic diseases. Understanding these various quantitative interference pattern analysis modalities will not only improve the ability of physiatrists to interpret electromyographic findings, but will also expand their knowledge of motor unit diseases.

Establishment of Clouds of Envelope Amplitude-Activity and Number of Small Segments-Activity in Normal Adults

OBJECTIVE: To establish the envelope amplitude-activity and number of small segments (NSS)-activity clouds of normal adults using the interference pattern of quantitative electromyography (EMG). METHOD: Healthy adults whose ages were from 20 to 59 years old participated in this study. Using quantitative EMG of the biceps brachii, vastus medialis, and tibialis anterior muscle, the interference patterns were analyzed. The interference patterns were measured at three to five different force levels, ranging from minimum to maximum, and recorded at least 20 epochs at each muscle. RESULTS: The envelope amplitude-activity and NSS-activity ratio of the biceps brachii, vastus medialis, and tibialis anterior muscles were obtained in males and females. The establishment of normal clouds of gender related envelope amplitude-activity and NSS-activity were obtained. CONCLUSION: By using the above normal clouds of envelope amplitude-activity and NSS-activity, automatic interference pattern analysis may contribute to early diagnosis and detection of progress of myopathy and neuropathy.

Analysis of Interference Pattern of Quantitative Electromyography in Early Adolescence

OBJECTIVE: To establish turns-amplitude, activity-envelope amplitude and activity-number of small segements (NSS) clouds of normal early teens using interference pattern. METHOD: Forty four healthy early adolescence from 11 to 15 years old participated in this study. The interference patterns were analyzed using quantitative electromyography of the biceps brachi and tibialis anterior muscles. The interference patterns were measured at 3 to 5 different force levels ranging from minimum to maximum and turns, mean amplitude, activity, envelope amplitude, NSS were analyzed. By turns/amplitude, activity/envelope amplitude and activity/ NSS ratio, normal clouds of gender related each parameters were obtained. RESULTS: The turns-amplitude, activity-envelope amplitude and activity-NSS ratio of the biceps brachii and tibialis anterior muscles were obtained. Normal clouds of gender related turns-amplitude, activity-envelope amplitude and activity-NSS for each muslces were established. CONCLUSION: By using normal cloud patterns of turns- amplitude, activity-envelope amplitude and activity-NSS, automatic interference pattern analysis may contribute to diagnose neuromuscular disease in early adolescent patients.

Changes of Electromyographic Signals Following Peripheral Nerve Injury

Quantitative analysis of abnormal spontaneous activities, motor unit action potentials and interference patterns were recorded in 55 subjects with traumatic peripheral nerve injury to understand the changes of electromyographic signals. We analyzed amplitudes of fibrillation potentials and positive sharp waves at rest, amplitude, duration, spike duration and polyphasicity of motor unit action potentials at minimal contraction, and the root mean square(RMS), and mean rectified voltage (MRV) at maximal contraction. The amplitudes of fibrillation potentials and positive sharp waves had negative correlations with the duration of peripheral nerve injury but the amplitudes of motor unit action potentials, RMS, and MRV had positive correlations. Therefore electromyographic evaluation could be used for the estimation of the duration of peripheral nerve injury.

Quantitative Turns/Amplitude Analysis of Interference Pattern in Neuromuscular Diseases

The present study was designed to evaluate the diagnostic efficacy and the clinical usefulness of quantitative analysis of interf erence pattern in differentiating the neuromuscular diseases. To obtain the normal control value, the automatic turns/amplitude analysis of interference pattern in biceps brachii and tibialis anterior muscle was done in 30 healthy normal subjects. The same procedure was performed in 16 patients with myopathy and 14 neuropathy to determine the diagnostic sensitivity of this method. Original pairs of turns/amplitude data obtained from controls converted into the logarithmic scale and linear regression equation, were calculated. Boundary of normal cloud was defined by the + 2 S. D. lines, maximum turn and amplitude. The result was considered abnormal if two or more turns/amplitude values were outside the zone normal cloud. The values of myopathic patients shifted toward the right lower quadrant meaning high turns and small amplitudes, but those of neuropathic patients shifted toward the left upper quadrant meaning few turns and large amplitudes. In all subjects of each patient group, at least two turns/amplitude values were outside the zone of normal cloud. In addition, the sequential changes of mean turns/amplitude ratio were well correlated with the disease activity. These results suggest that this method of automatic turns/amplitude analysis could be used not only as a supplementary diagnostic tool in differentiating the neuromuscular disorders, but also a parameter of monitoring the disease activity.

Preliminary Researches for the Causes of Maltese-Cross Formed in Biological Liquid Crystals / 昆明医科大学学报

We studied the causes of Maltese-cross formed in biological liquid crystals. We conidered that the Maltese-cross is a kind of interfernce pattern of polarized light which passed through the biological liquid crystal. We had observed different interfernce patterns which were differ- ent shapes of Maltese-cross, under a convergent, perpendicular, polarized light micro- scope because the light-axis direction in biological liquid crystals is at pleasure.