Ulnar nerve conduction velocity in injured baseball pitchers

OBJECTIVE: To compare the ulnar nerve conduction velocity (NCV) of baseball pitchers without elbow injury to baseball pitchers with elbow injury and to persons who do not play baseball. DESIGN: Cross-sectional. SETTING: Hospital rehabilitation department. PARTICIPANTS: Eight college baseball pitchers without elbow injury, 8 age-matched controls who did not play baseball, and 8 college baseball pitchers with a history of elbow injury with tenderness over the cubital tunnel area. INTERVENTION: Supramaximal electric stimulation was applied superficially to the ulnar nerve at the wrist, below the elbow, and above the elbow of both the dominant and nondominant arms of all subjects. M waves were recorded from the abductor digiti minimi muscles. MAIN OUTCOME MEASURES: The ulnar NCV was calculated separately for the across-elbow and below-elbow segments. The ulnar NCVs of both arms of the 3 groups were compared by using a 2-way (arm by group) analysis of variance, with a statistical significance level of P less than .05. RESULTS: The ulnar NCVs were 64.40+/-7.34m/s, 54.97+/-8.67m/s, and 59.18+/-4.10m/s for the pitchers without injury, pitchers with injury, and the subjects who were not pitchers, respectively. The pitchers without injury were significantly faster than the other 2 groups. For pitchers without injury, the ulnar NCVs of the dominant arm were significantly faster than those of the nondominant arm (56.26+/-2.63m/s). No significant difference was found between the dominant and nondominant arms for the group of injured pitchers and for the group of subjects who were not pitchers. CONCLUSIONS: The ulnar NCVs of the injured pitchers did not appear to be abnormal, but were suboptimal in comparison with the noninjured pitchers. The above-normal NCVs observed in the noninjured pitchers may be the result of an adaptation to trauma associated with ball throwing.     

Ulnar nerve conduction velocity as function of wrist position

Ulnar nerve conduction velocity (CV) calculated across the elbow has been shown to be significantly influenced by the position of the elbow. This study investigated the effect of wrist position on ulnar nerve CV in 19 control subjects. Ulnar nerve CV was determined with the elbow flexed at 90 degrees at two different wrist positions. The below-elbow-to-wrist CV was not significantly different between the wrist extended and the wrist flexed. Similarly, the mean across-elbow CV with wrist extended was not significantly different from the CV with the wrist flexed. The authors conclude that wrist position does not affect the calculated ulnar nerve CV across the elbow.     

双侧正中神经、尺神经多节段运动神经传导各参数正常值的建立

目的：建立双侧正中神经、尺神经多节段运动神经传导速度（MCV）、潜伏期(LAT)和波幅(AMP)的正常值。方法：200例健康志愿者,男100例,女100例,分别按年龄分成5组,正中神经记录点在拇短展肌,刺激点分别为掌点、腕点、肘点、腋点、Erb点;尺神经记录点在小指展肌,刺激点分别为腕点、肘下点、肘上点、腋点、Erb点,记录各段MCV、LAT、AMP值。结果：正中神经、尺神经多节段MCV 、LAT、AMP与性别、侧别无相关性;年龄与正中神经各段MCV、LAT、AMP及尺神经AMP有关。 结论：双侧正中神经、尺神经多节段运动神经传导的准确检测对临床疾病诊断有重要价值。     

计算机辅助对冲技术测定运动神经纤维传导速度分布的研究

目的:研究计算机辅助对冲技术的主要影响因素及运动纤维传导速度分布的正常值。方法:选择2004-05/2005-03知情同意的健康志愿者29人进行计算机辅助对冲技术检测,测定了正中、尺及腓总神经传导速度分布正常值范围,并对最慢纤维传导速度(慢纤维速度)的影响因素进行回归分析。观察了2名健康人不同肢体皮温(变化范围2～4℃)的传导速度分布结果和10名健康人的不同计算机辅助对冲技术刺激强度(最大、最大 15%～50%)传导速度分布的变化。对5名健康人的相同神经采用相同的计算机辅助对冲技术参数和方法分别进行3次重复检测,观察其结果的一致性和可重复性。结果:①室温20～22℃,肢体皮温(31.9±0.89)℃情况下,测得传导速度分布正常值,正中神经最慢速度(慢纤维速度CV10%)(47.31±4.58)m/s、中等速度(中速纤维速度CV50%)(52.17±3.78)m/s、最快速度(快纤维速度CV90%)(56.14±5.13)m/s;尺神经慢纤维速度(48.46±6.0)m/s、中速纤维速度(53.11±5.16)m/s、快纤维速度(57.33±5.04)m/s;腓总神经慢纤维速度(35.58±5.98)m/s、中速纤维速度(41.61±4.76)m/s、快纤维速度(46.04±3.50)m/s。②回归分析显示:身高、皮温和年龄与慢纤维速度呈负相关,身高是慢纤维速度最显著的影响因素(P=0.013)。③肢体皮温下降2℃时的传导速度分布结果与标准皮温比较无明显变化,下降4℃的传导速度分布数值明显降低,快纤维速度降低7～10m/s,慢纤维速度降低3～9m/s。④最大刺激强度和超强刺激(最大刺激量 15%～50%)的传导速度分布结果比较显示<50m/s的纤维分布明显减少,而快纤维速度无明显差别;超强刺激强度变化对传导速度分布结果无明显影响(P=0.999)。⑤计算机辅助对冲技术重复实验传导速度分布结果显示各组之间无显著差异(P正中=0.649,P腓总=0.984)。结论:计算机辅助对冲技术对研究不同传导速度的运动神经纤维具有重复性好、无创和敏感性高的特点,能更全面评价运动神经传导特性。因此计算机辅助对冲技术可能在周围神经病变的早期诊断,尤其是发现亚临床病变具有重要临床意义。     

计算机辅助对冲技术测定运动神经纤维传导速度分布的研究

目的：研究计算机辅助对冲技术的主要影响因素及运动纤维传导速度分布的正常值。方法：选择2004—05／2005—03知情同意的健康志愿者29人进行计算机辅助对冲技术检测，测定了正中、尺及腓总神经传导速度分布正常值范围，并对最慢纤维传导速度（慢纤维速度）的影响因素进行回归分析。观察了2名健康人不同肢体皮温（变化范围2～4℃）的传导速度分布结果和10名健康人的不同计算机辅助对冲技术刺激强度（最大、最大&;#177;15％～50％）传导速度分布的变化。对5名健康人的相同神经采用相同的计算机辅助对冲技术参数和方法分别进行3次重复检测，观察其结果的一致性和可重复性。结果：①室温20～22℃，肢体皮温（31．9&;#177;0．89）℃情况下，测得传导速度分布正常值，正中神经最慢速度（慢纤维速度CV10%）（47．31&;#177;4．58）m／s、中等速度（中速纤维速度CV50％）（52．17&;#177;3．78）m／s、最快速度（快纤维速度CV90%）（56．14&;#177;5．13）m／s；尺神经慢纤维速度（48．46&;#177;6．0）m／s、中速纤维速度（53．11&;#177;5．16）m／s、快纤维速度（57．33&;#177;5．04）m／s；腓总神经慢纤维速度（35．58&;#177;5．98）m／s、中速纤维速度（41．61&;#177;4．76）m／s、快纤维速度（46．04&;#177;3．50）m／s。②回归分析显示：身高、皮温和年龄与慢纤维速度呈负相关，身高是慢纤维速度最显著的影响因素（P=0．013）。③肢体皮温下降2℃时的传导速度分布结果与标准皮温比较无明显变化，下降4℃的传导速度分布数值明显降低，快纤维速度降低7～10m／s，慢纤维速度降低3～9m／s。④最大刺激强度和超强刺激（最大刺激量&;#177;15％～50％）的传导速度分布结果比较显示〈50m／s的纤维分布明显减少，而快纤维速度无明显差别；超强刺激强度变化对传导速度分布结果无明显影响（P=0．999）。⑤计算机辅助对冲技术重复实验传导速度分布结果显示各组之间无显著差异（P正中=0．649，P腓总=0．984）。结论：计算机辅助对冲技术对研究不同传导速度的运动神经纤维具有重复性好、无创和敏感性高的特点，能更全面评价运动神经传导特性。因此计算机辅助对冲技术可能在周围神经病变的早期诊断，尤其是发现亚临床病变具有重要临床意义。     

Radial motor nerve conduction studies

The radial motor nerve fibers were studied in 30 subjects using a technique of surface stimulation in the axilla and the antecubital fossa. Surface recording over the extensor digitorum communis 8cm from the distal stimulation site was done. Mean distal latency was 2.6msec (SD = 0.44), amplitude 11.24mV (SD = 3.5), and conduction velocity 68m/sec (SD = 7.0). Side-to-side comparison using the t-test demonstrated no significant differences. Five subjects were tested 75 more times on two successive days and showed a variation in latency of 0.2msec or less in 74 of 75 trials. Amplitude was consistent during each day's trial, but it varied slightly from one day to the next. Three case reports show the usefulness of the procedure.     

Ulnar nerve conduction study of the first dorsal interosseous muscle

Ulnar neuropathy at or distal to the wrist is difficult to diagnose. Sensation is normal in the majority of cases, and the interosseous muscles are usually more severely involved than are the hypothenar muscles. A technique for ulnar nerve conduction study of the first dorsal interosseous muscle is described, and normal values based upon 373 studies are presented. Using this technique the upper limit for distal motor latency (DML) to the first dorsal interosseous (FDI) muscle is 4.5 ms. More precisely, DML to the FDI should not exceed DML to the contralateral FDI by more than 1.3 ms, nor should this value exceed the DML to the ipsilateral abductor digiti minimi by more than 2.0 ms. The lower limit for amplitude of the compound muscle action potential recorded over FDI is 6mV. If motor conduction study of the first dorsal interosseous muscle is more routinely performed, earlier and more frequent recognition could be followed by improved surgical remediation of this compression neuropathy.     

Measurement of motor nerve conduction velocity of the sciatic nerve in patients with piriformis syndrome: a magnetic stimulation study

OBJECTIVE: To assess the motor nerve conduction of the sciatic nerve by a magnetic stimulation method in patients with piriformis syndrome. DESIGN: Prospective study. SETTING: An electrodiagnostic laboratory in a university hospital. PARTICIPANTS: Twenty-three patients with piriformis syndrome and 15 healthy persons for control. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Motor nerve conduction velocity (MNCV) of the sciatic nerve was measured at the gluteal segment by magnetic stimulation proximally at L5 and S1 roots and distally at sciatic nerve at gluteal fold and recording at the corresponding muscles. Diagnostic sensitivities were measured in the magnetic stimulation method and the conventional nerve conduction, long latency reflex, and needle electromyography studies. RESULTS: The mean MNCV of the sciatic nerve +/- standard deviation at the gluteal segment in L5 component was 55.4+/-7.8 m/s in patients with piriformis syndrome, which was slower than the mean value of 68.1+/-10.3 m/s obtained in healthy controls (P=.014). The MNCV of the sciatic nerve in S1 component showed no significant difference between the patients and controls (P=.062). A negative relation was found between the disease duration and the MNCV values of sciatic nerves in patients with piriformis syndrome (r=-.68, P<.01). The diagnostic sensitivity by magnetic stimulation is .467. CONCLUSIONS: Magnetic nerve stimulation provides a painless, noninvasive, and objective method for evaluation of sciatic nerve function in patients with piriformis syndrome.     

Ulnar palmar cutaneous nerve and hypothenar sensory conduction studies.

The ulnar palmar cutaneous nerve (UPCN) is potentially useful to the electrodiagnostician. However, no definitive nerve conduction study techniques for the UPCN have been reported. The UPCN supplies sensory innervation to the hypothenar palm. This study describes an orthodromic sensory conduction technique for the hypothenar palm. Data were collected from 20 normal limbed patients (ages 22-58). Potentials were recorded over the ulnar nerve 10cm proximally and at the elbow. Distal latency was 2.19 +/- 0.17msec, and distal amplitude was 12.7 +/- 6.9uv. Additionally, a modified collision technique was used in several subjects to examine the possibility of volume conduction to more than one ulnar nerve branch. The techniques described may be useful in selected cases of distal ulnar nerve pathology. A case is reported in which injury to the superficial sensory branch of the ulnar nerve, with sparing of the UPCN was demonstrated electrodiagnostically. Further study is needed to determine if the UPCN can consistently be electrophysiologically isolated.