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Distal dorsal ulnar cutaneous nerve conduction technique: normative data
32P
Society proceedings / Elecrroencephulography and clinical Neurophysiology 98 11996) 8P-4OP
neous excitation of the ulnar nerve, and is recommended for clinical practice. Study supported by MetroHealth Medical Center, Department of Physical Medicine and Rehabilitation. 119. Active electrode placement and compound muscle action potential amplitude. - M.B. Bromberg ’ and T. Spiegelbergb (” University of Utah, Salt Lake City, UT; b University of Michigan, Ann Arbor, MI) Introduction: Guidelines for active electrode placement include measured distances and visual estimations. An initial negative deflection indicates proper positioning “over” the motor point. The motor point, however, may cover a large area. Objective: We evaluated compound muscle action potential (CMAP) amplitudes at different electrode positions chosen by a variety of electromyographers. Methods: Eight electromyographers and two technologists placed the active electrode as they wished over 4 muscles on the same subject. Placement sites were marked with invisible ink. Results: Electrode placement and CMAP negative peak amplitude varied with no pattern based on type or level of electromyographic experience. The range of amplitudes expressed as a percentage of the maximal response (lowest value, median value) was: thenar (631, 87%), hypothenar (71%. 86%), extensor digitorum brevis (EDB) (69%, 77%), abductor hallucis (AH) (7.5%. 92%). Correlations of amplitude with rise time were poor (r = 0.02-0.58). Correlations with slope of the negative deflection were better but variable: thenar (r = 0.68, P = 0.03) hypothenar (initial negative wave r = 0.40, P = 0.26, second negative wave r = 0.72, P = 0.021, EDB (r = 0.94, P = O.OOOl),AH (r = 0.42, P = 0.30). Conclusions: CMAP amplitudes were underestimated but median values were reasonable estimates. Visual assessment of waveforms did not reliably predict low amplitudes. When a low amplitude is suspected empiric repositioning of the active electrode is advisable. 120. Distal dorsal ulnar cutaneous nerve conduction technique: normative data. - E.L. DeVos and S.Q. Huang (MetroHealth Medical Center, Case Western Reserve University, Cleveland, OH) Introduction:Dorsal ulnar cutaneous nerve (DUCN) conduction technique stimulating 8 cm proximal to the ulnar styloid is often technically difficult due to ulnar motor nerve interference. Recently, a proposed new technique eliminated such motor contamination by stimulating more distally just volar to the ulnar styloid (Park et al., Muscle Nerve, 1994, 17: 1082). Objective: To confirm the superiority and reliability of and to establish a range of normal values for the distal DUCN conduction technique. Methods: DUCN conduction studies were performed on 60 asymptomatic hands, aged 24-55 years, utilizing an active recording electrode in the fourth web space and stimulating percutaneously 5 cm proximal just volar to the ulnar styloid. Results: Mean peak latency = 1.7f 0.22 msec, mean onset latency = 1.2 f 0.22 msec, mean amplitude = 27 PV (range 4-81 @VI, mean conduction velocity = 41.5 f 7.3 m/set. Conclusions: DUCN conduction response with stimulation just volar to the ulnar styloid is more easily obtained than with more proximal stimulation and produces a clearer response without motor interference. Our data are compatible with published data of DUCN responses obtained with more proximal stimulation. 121. Index finger length and antidromic median nerve sensory conduction. - H.J. Lee ” and H.-K. Kwon b, (” UMD-New Jersey Medical School, Newark, NJ; b Korea University College of Medicine, Seoul, Korea) Latencies and amplitudes on nerve conduction studies are affected by many factors including height. This study describes a possible relation-
ship between the length of the 2nd digit and the antidromic median nerve sensory conduction. Recording ring electrodes were placed on the 2nd digit with a 4 cm separation. The stimulating cathode was placed 14 cm proximal to the active electrode. Skin temperature was maintained at 33°C or above. Second digit lengths were measured from the midpoint of the proximal digital crease to the tinger tip. Finger circumferences were also measured. Onset latencies and amplitudes from baseline to negative peak were measured in 30 nerves in 30 normal adult subjects, aged 25-67 years (mean 38). A positive linear correlation was found between the finger length and onset latency (r = 0.58, P = O.ooO8). Inverse correlations were found between the amplitude and fmger length (r = 0.51, P = 0.004). and circumference (r = 0.40, P = 0.03). Failure to consider the 2nd digit length when interpreting the results of antidromic median nerve sensory conduction may result in a decrease in diagnostic sensitivity. 122. Semiquantification of fibrillation with intramuscular temperature reduction. - H.J. Lee ‘, H.-K. Kwon b and M.-O. Kii ’ (” UMD-New Jersey Medical School, Newark, NJ; b Korea University College of Medicine, Seoul, Korea) It is well known that the quantity of fibrillation potentials (FP) decreases with drop in the intramuscular temperature.. We describe the semiquantitative measurement of FP and positive waves (PW) with intramuscular temperature changes in an experimental animal (rat, Sprague-Dawley). Using intraperitoneal sodium pentobarbital, the right sciatic nerve of 4 rats was surgically isolated. A 1 cm segment was excised after tying the proximal and distal ends of the nerve segment. A concentric needle and thermometer needle probe were inserted 1 cm apart into the posterior tibia1 muscles 3-4 days after nerve injury. Before and during cooling the muscles with ice, FP and PW were measured and electronically stored for later analysis. Visually recognizable potentials (30 PV or above) in each stored tracing with temperature changes (range, 3PC to 15°C) were counted. A positive linear correlation was found between the temperature changes and the quantity of denervation activities. The recording of denervation activities (FP and PW) completely ceased at approximately 20°C below baseline temperature. In this study, we have successfully semiquantified denervation activities in a wide range of intramuscular temperature reduction. 123. Chronic fatigue syndrome patients demonstrate abnormalities of autonomic nervous system function. - J.A. Cohen’, D.L. Hamilos b, J. Gershtenson b and T.F. Jones b (” University of Colorado/Kaiser, Denver, CO; b National Jewish Hospital, Denver, CO) Introduction: Chronic fatigue syndrome (CFS) is poorly understood. CFS patients can complain of autonomic disturbances (syncope). An explanation is depression. Therefore, we studied the autonomic nervous system CANS) function in CFS, major depression and control subjects. Objective: We evaluated ANS in 3 groups: CFS ( 12 females, 3 males; aged 39.5 f 5.9), major depression (11 females, I male; aged 42.1 + 3.6) and normal control subjects (12 females; aged 45.1 f 6.0). Methods: CFS subjects were selected based on Centers for Disease Control criteria. Group measurements were compared by Student’s t test using the Tukey-Kramer test. Heart rate (HR) and blood pressure were recorded continuously, recumbent and 30 and 120 set after being tilted to 80” from horizontal. Skin sympathetic response (SSR) was measured at the hand and foot. Results: CFS but not depressed subjects demonstrated a greater mean increase in HR after tilting for 30 set and 120 set than control subjects. The mean latency of the foot SSR in CFS subjects (foot: 2.25 set) was significantly slower than control subjects (foot: 1.50 see) or depressed subjects (foot: I .5 1 set).
Society proceedings / Elecrroencephulography and clinical Neurophysiology 98 11996) 8P-4OP
neous excitation of the ulnar nerve, and is recommended for clinical practice. Study supported by MetroHealth Medical Center, Department of Physical Medicine and Rehabilitation. 119. Active electrode placement and compound muscle action potential amplitude. - M.B. Bromberg ’ and T. Spiegelbergb (” University of Utah, Salt Lake City, UT; b University of Michigan, Ann Arbor, MI) Introduction: Guidelines for active electrode placement include measured distances and visual estimations. An initial negative deflection indicates proper positioning “over” the motor point. The motor point, however, may cover a large area. Objective: We evaluated compound muscle action potential (CMAP) amplitudes at different electrode positions chosen by a variety of electromyographers. Methods: Eight electromyographers and two technologists placed the active electrode as they wished over 4 muscles on the same subject. Placement sites were marked with invisible ink. Results: Electrode placement and CMAP negative peak amplitude varied with no pattern based on type or level of electromyographic experience. The range of amplitudes expressed as a percentage of the maximal response (lowest value, median value) was: thenar (631, 87%), hypothenar (71%. 86%), extensor digitorum brevis (EDB) (69%, 77%), abductor hallucis (AH) (7.5%. 92%). Correlations of amplitude with rise time were poor (r = 0.02-0.58). Correlations with slope of the negative deflection were better but variable: thenar (r = 0.68, P = 0.03) hypothenar (initial negative wave r = 0.40, P = 0.26, second negative wave r = 0.72, P = 0.021, EDB (r = 0.94, P = O.OOOl),AH (r = 0.42, P = 0.30). Conclusions: CMAP amplitudes were underestimated but median values were reasonable estimates. Visual assessment of waveforms did not reliably predict low amplitudes. When a low amplitude is suspected empiric repositioning of the active electrode is advisable. 120. Distal dorsal ulnar cutaneous nerve conduction technique: normative data. - E.L. DeVos and S.Q. Huang (MetroHealth Medical Center, Case Western Reserve University, Cleveland, OH) Introduction:Dorsal ulnar cutaneous nerve (DUCN) conduction technique stimulating 8 cm proximal to the ulnar styloid is often technically difficult due to ulnar motor nerve interference. Recently, a proposed new technique eliminated such motor contamination by stimulating more distally just volar to the ulnar styloid (Park et al., Muscle Nerve, 1994, 17: 1082). Objective: To confirm the superiority and reliability of and to establish a range of normal values for the distal DUCN conduction technique. Methods: DUCN conduction studies were performed on 60 asymptomatic hands, aged 24-55 years, utilizing an active recording electrode in the fourth web space and stimulating percutaneously 5 cm proximal just volar to the ulnar styloid. Results: Mean peak latency = 1.7f 0.22 msec, mean onset latency = 1.2 f 0.22 msec, mean amplitude = 27 PV (range 4-81 @VI, mean conduction velocity = 41.5 f 7.3 m/set. Conclusions: DUCN conduction response with stimulation just volar to the ulnar styloid is more easily obtained than with more proximal stimulation and produces a clearer response without motor interference. Our data are compatible with published data of DUCN responses obtained with more proximal stimulation. 121. Index finger length and antidromic median nerve sensory conduction. - H.J. Lee ” and H.-K. Kwon b, (” UMD-New Jersey Medical School, Newark, NJ; b Korea University College of Medicine, Seoul, Korea) Latencies and amplitudes on nerve conduction studies are affected by many factors including height. This study describes a possible relation-
ship between the length of the 2nd digit and the antidromic median nerve sensory conduction. Recording ring electrodes were placed on the 2nd digit with a 4 cm separation. The stimulating cathode was placed 14 cm proximal to the active electrode. Skin temperature was maintained at 33°C or above. Second digit lengths were measured from the midpoint of the proximal digital crease to the tinger tip. Finger circumferences were also measured. Onset latencies and amplitudes from baseline to negative peak were measured in 30 nerves in 30 normal adult subjects, aged 25-67 years (mean 38). A positive linear correlation was found between the finger length and onset latency (r = 0.58, P = O.ooO8). Inverse correlations were found between the amplitude and fmger length (r = 0.51, P = 0.004). and circumference (r = 0.40, P = 0.03). Failure to consider the 2nd digit length when interpreting the results of antidromic median nerve sensory conduction may result in a decrease in diagnostic sensitivity. 122. Semiquantification of fibrillation with intramuscular temperature reduction. - H.J. Lee ‘, H.-K. Kwon b and M.-O. Kii ’ (” UMD-New Jersey Medical School, Newark, NJ; b Korea University College of Medicine, Seoul, Korea) It is well known that the quantity of fibrillation potentials (FP) decreases with drop in the intramuscular temperature.. We describe the semiquantitative measurement of FP and positive waves (PW) with intramuscular temperature changes in an experimental animal (rat, Sprague-Dawley). Using intraperitoneal sodium pentobarbital, the right sciatic nerve of 4 rats was surgically isolated. A 1 cm segment was excised after tying the proximal and distal ends of the nerve segment. A concentric needle and thermometer needle probe were inserted 1 cm apart into the posterior tibia1 muscles 3-4 days after nerve injury. Before and during cooling the muscles with ice, FP and PW were measured and electronically stored for later analysis. Visually recognizable potentials (30 PV or above) in each stored tracing with temperature changes (range, 3PC to 15°C) were counted. A positive linear correlation was found between the temperature changes and the quantity of denervation activities. The recording of denervation activities (FP and PW) completely ceased at approximately 20°C below baseline temperature. In this study, we have successfully semiquantified denervation activities in a wide range of intramuscular temperature reduction. 123. Chronic fatigue syndrome patients demonstrate abnormalities of autonomic nervous system function. - J.A. Cohen’, D.L. Hamilos b, J. Gershtenson b and T.F. Jones b (” University of Colorado/Kaiser, Denver, CO; b National Jewish Hospital, Denver, CO) Introduction: Chronic fatigue syndrome (CFS) is poorly understood. CFS patients can complain of autonomic disturbances (syncope). An explanation is depression. Therefore, we studied the autonomic nervous system CANS) function in CFS, major depression and control subjects. Objective: We evaluated ANS in 3 groups: CFS ( 12 females, 3 males; aged 39.5 f 5.9), major depression (11 females, I male; aged 42.1 + 3.6) and normal control subjects (12 females; aged 45.1 f 6.0). Methods: CFS subjects were selected based on Centers for Disease Control criteria. Group measurements were compared by Student’s t test using the Tukey-Kramer test. Heart rate (HR) and blood pressure were recorded continuously, recumbent and 30 and 120 set after being tilted to 80” from horizontal. Skin sympathetic response (SSR) was measured at the hand and foot. Results: CFS but not depressed subjects demonstrated a greater mean increase in HR after tilting for 30 set and 120 set than control subjects. The mean latency of the foot SSR in CFS subjects (foot: 2.25 set) was significantly slower than control subjects (foot: 1.50 see) or depressed subjects (foot: I .5 1 set).