Electrophysiological aspects of sensory conduction velocity in healthy adults. 2. Ratio between the amplitude of sensory evoked potentials at the wrist on stimulating different fingers in both hands.

Abstract

S U M M ARY The normal ratio between the amplitude of the sensory evoked potential (SEP) at the wrist on stimulating digits 1, 2, 3, and 5 was determined in 44 healthy adult subjects. The first digit had the larger amplitude, and the fifth digit the smallest SEP. The amplitude expresses the density of sensory innervation in each finger. The ratio between the amplitude of different fingers varied according to the age of the subject. The amplitude of the SEP from a digit innervated by the median nerve decreased in the elderly more than the SEP amplitude of the digit innervated by the ulnar nerve, probably because of a chronic compression in the carpal tunnel. The changes in the normal amplitude ratio can be applied to the topographic diagnosis of radicular and brachial plexus lesions if a fixed segmental sensory innervation of the hand is accepted. In 44 right handed subjects the amplitude of the sensory evoked potentials at the wrist was significantly larger in the left hand. This asymmetry of sensory innervation between hands could be physiological, and suggests a greater density of sensory innervation in the left hand of right handed subjects.

Nerve conduction normal values for electrodiagnosis in pediatric patients

“…The largest study we found included 372 newborns, infants, and children, 11,12 whereas most others had fewer than 200 patients. 7,10,[13][14][15][16][17][18][19]21,24 Very few data on establishing normal pediatric NCS values have been published in the last 15 years, although a notable study reported normal values for the femoral nerve. 22 We created comparison tables of our data vs. those of previous studies (see Tables S1-4 online).…”

“…2,6 Since then, multiple studies establishing normal values in pediatric NCS have been reported. [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22] The sample sizes in these normative studies were relatively small, especially when compared with the higher volumes seen in referral centers in recent years. Furthermore, many laboratories have reported their own pediatric reference values when discussing normal or abnormal EDx results, without a clear explanation of the methodology used to obtain these values.…”

Clinical, genetic and electrophysiologic correlation in hereditary neuropathy with liability to pressure palsies with involvement of PMP22 gene at chromosome 17p11.2

“…Orthodromic conduction of the sural nerve was calculated by recording the potential at the mid calf after stimulation at the ankle. More details of conduction study methods and normal values used in our laboratory for different ages have been reported (Cruz-Martinez et al, 1977a, 1978a.…”

Principles and pitfalls of nerve conduction studies

“…Substantial slowing in conduction velocity implies demyelination of the sensory fibers, whereas axonotmesis results in reduced amplitude of compound nerve action potentials with stimulation distal to the site of lesion. Degeneration of sensory fibers occurs only with a postganglionic lesion, such as plexopathy or peripheral neuropathy [12). This fact can be used as a criterion in differentiating postganglionic from preganglionic disorders, such as syringomyelia or root avulsion.…”