Electrophysiological findings in chronic obstructive pulmonary disease; nerve transmission evaluation, MUP analysis, interferance pattern analysis, macro EMG, motor unit number estimation

Chronic obstructive pulmonary disease (COPD) is an inflammatory process withlimitation of the airflow in the lung. COPD is a chronic and progressive process that leads totissue hypoxemia and thereby affects lung and the whole body. There are some studiesreporting the damage of peripheral nerves and muscles in this process. But, the number ofthese reports and also the sensitivity of these methods for the demonstrating of damage werelimited.In this study, some electrophysiological methods which investigate nerve and musclefunctions (nerve conduction study, motor unit potential analysis, interference pattern analysis,macro electromyography and motor unit number estimation) were used to find any similaritiesand differences between in patients who diagnosed as COPD and in normal individuals.This study was performed in Adnan Menderes University Medical Faculty at thedepartments of Neurology and Chest Diseases. 32 COPD patients and 28 voluntary healthyindividual (totally 60 patients) were involved in the study. All of them were male and were insimilar ages (COPD 63,09±7,65; normal 61,50±7,27).In nerve conduction study, ulnar sensory latency and velocity, sural sensory durationand latency, and ulnar motor distal latency values were different in the COPD group than thenormal. (Latency and duration were long, and velocity was decreased). While abnormalityrate was not different statistically between in these groups (COPD 40,6 %; normal 21,4 %),the COPD group revealed high abnormality ratio (1,89) than the normal. Nerve damage mightbe isolated sensory, isolated motor or both nerves, and nerve damage was not related withpatients? age and COPD severity. In motor unit potential analysis, phase and turn values ofmotor unit potential were increased while duration, area, area/amplitude ratio, and size indexvalues of motor unit potential were decreased in COPD group compared to normal. Ininterference pattern analysis turn, activity and number of short segment values of motor unitpotential were increased, but amplitude value was decreased in COPD group compared tonormal. In motor unit number estimation test, while the thenar and hypothenar region MUNEvalues were not different in these two groups, better motor unit number count was detected onthe tibialis anterior muscle in COPD group than normal. In macro EMG analysis, resultsfound similar in both COPD and normal group.All types of nerve damage can be seen in COPD cases. We did not observedstatistically significant difference between COPD group and normal, but there was a highabnormality ratio in COPD group. Findings gathered from MUP analysis and interferencepattern analysis were similar to findings that observed when there were muscle fiber loss andmuscle fiber diameter changes. These electrophysiological findings may reflect thepathological changes of muscle fibers that loss of type I muscle fibers and increased of type IImuscle fibers in COPD patients. In macro EMG analysis, because of absence of statisticallysignificant difference between groups suggested that motor unit area did not increase inCOPD patients. Better fibular MUNE values observed in motor unit number estimationmethod couldn?t be explained. According to principal component analysis and discriminantanalysis, all performed electrophysiological investigations classified groups accurately at arate of 68,3 %. The most distinguishing parameters were the results of ulnar sensory nerveconduction velocity and the results of interference pattern analysis of biceps brachii muscle.Key words: COPD, nerve conduction study, motor unite potential analysis, interferencepattern analysis, IPA, macro EMG, axon counting, MUNE, basic components analysis,detachment analysis.