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Sensory Action Potentials (sensory + action_potential)
Selected AbstractsElectrophysiological Changes In Diabetic Neuropathy: From Subclinical Alterations To Disabling AbnormalitiesJOURNAL OF THE PERIPHERAL NERVOUS SYSTEM, Issue 3 2000M. Baba Clinical spectrum of diabetic neuropathy is variable; it may be asymptomatic, but once established, it becomes irreversible and disabling. Some investigators suggested that earliest change in diabetic nerve function is alteration in axonal excitability due to alterations in ion conductance of axon membrane, although these functional changes of ion channels necessarily cause permanent damage or degeneration of nerve fibers. Among various parameter of nerve conduction study in diabetics, prolonged F-wave latency in the peroneal and tibial nerve seems the commonest abnormality in asymptomatic patients. Decrease in amplitude of compound sensory action potential of sural nerve is another earlier abnormality, which is, then, accompanied by a fall in motor amplitude of peroneal and tibial nerves in advanced patients. In disabled patients no motor response is often elicited in the legs. Previous electrophysiological studies could not make clear if central axons were involved or not in diabetic neuropathy. Recently, our group has demonstrated that somatosensory central conduction from the spinal cord to the sensory cortex is delayed in diabetics as well as in the peripheral conduction, which might be partly responsible for the irreversible clinical presentation of diabetic neuropathy. [source] The significance of second lumbrical-interosseous latency comparison in the diagnosis of carpal tunnel syndromeACTA NEUROLOGICA SCANDINAVICA, Issue 3 2009A. A. Argyriou Aim,,, To assess the significance of the second lumbrical-interosseous latency (2LI-DML) comparison in the diagnosis of carpal tunnel syndrome (CTS). Patients and methods,,, We examined 150 consecutive hands of patients referred with suspected CTS, using the 2LI-DML test and other standard measures of median nerve function. Correlations of the 2LI-DML test with standard tests were computed. Results,,, Hundred and four hands were electrophysiologically confirmed to have CTS. The 2LI-DML test was abnormal in 99/104 (95.2%) hands with CTS with a mean value of 1.54 ± 1.12 ms. Among the other measures, the orthodromic median,ulnar palmar velocity comparison was the most frequently abnormal test (95/104 hands, 91.3%), followed by the double-peak morphology of orthodromic sensory action potential from digit 4 (94/104, 90.4%). The 2LI-DML test significantly correlated, either positively or negatively, with all other standard tests. Conclusion,,, The 2LI-DML comparison is highly sensitive in diagnosing CTS, even in mild cases in which standard tests fail to detect abnormalities. [source] Abstracts of the 8th Meeting of the Italian Peripheral Nerve Study Group: 73JOURNAL OF THE PERIPHERAL NERVOUS SYSTEM, Issue 1 2003C Inglese Cryoglobulinemic neuropathy is probably the commonest form of vasculitic neuropathy in Mediterranean countries, as usually related to the widespread hepatitis C virus (HCV) infection. We describe the spectrum of manifestations in a large series of patients with cryoglobulinemic neuropathy, also analyzing the impact of comorbid factors, which are quite frequent in HCV-related mixed cryoglobulinemia. The cohort included 60 patients (10 men, 50 women) with peripheral neuropathy associated with mixed cryoglobulinemia as main or sole cause (type 2 in 36 cases, type 3 in 4, not typized in 20), HCV-related in all patients but 8 (3 men and 5 women). Median age of patients was 65 years (range 41,85), and median age at onset of neuropathy was 59 (range 40,84). Peripheral neuropathy represented an onset manifestation of mixed cryoglobulinemia in about half patients. The most frequent clinical pattern was pure sensory neuropathy in 40 patients, including 4 patients with prominent ataxia; sensory neuropathy was asymmetrical in distribution in 9 patients, and in 14 patients sensory action potentials (SAPs) of the sural nerve were normal, suggesting selective involvement of the small sensory fibers. The remaining patients had sensorimotor neuropathy (15 cases) and mononeuropathy multiplex (5 cases). Positive sensory symptoms and restless legs syndrome were the most common manifestations. Neurophysiological study showed axonal degeneration of varying severity in all patients. In 20 patients, additional causes of neuropathy were present, including type 2 diabetes (5 patients), glucose intolerance (6 patients), non-Hodgkin lymphoma (3 patients), and alcohol (2 patients). With respect with this subset of patients, in "pure" cryoglobulinemic neuropathy there was more often a pattern of sensory neuropathy (31/40 vs. 6/20; p = 0.001), with more frequent asymmetrical distribution (9 vs 0; p = 0.05) and small fiber involvement (11 vs 3). Severity of neuropathy, as judged on the basis of the Rankin scale and of neurophysiological changes, was similar in the two subgroups. Our study confirms that sensory neuropathy, often asymmetrical, is the most common clinical pattern in cryoglobulinemic neuropathy, and is consistently present in pure cryoglobulinemic neuropathy rather than in patients with other associated causes of neuropathy; in these latter, paradoxically, clinical and neurophysiological impairment seems not greater than in pure cryoglobulinemic neuropathy. [source] Congenital hypomyelination neuropathy in a newborn infant: unusual cause of diaphragmatic and vocal cord paralysesJOURNAL OF THE PERIPHERAL NERVOUS SYSTEM, Issue 2 2002JS Hahn We report a case of congenital hypomyelination neuropathy presenting at birth. The infant had generalized hypotonia and weakness. There was decreased respiratory effort along with a right phrenic nerve and left vocal cord paralyses. Tongue fasciculations were present. Deep tendon reflexes were absent in the upper extremities and hypoactive (1+) in the lower extremities. Magnetic resonance imaging of the head revealed no intracranial abnormalities, including normal cerebral myelination. Nerve conduction study showed absence of motor and sensory action potentials in the hands when the nerves in the upper limbs were stimulated. A motor response could be elicited only in the proximal leg muscles. Needle electromyography study was normal in the proximal limb muscles, but showed active denervation in the distal muscles of the arm and leg. These findings were thought to be consistent with a length-dependent sensorimotor peripheral polyneuropathy of axonal type with greater denervation of the distal muscles. A biopsy of the quadriceps muscle showed mild variability in fiber diameter, but no group typing or group atrophy. The muscle fibers showed no intrinsic abnormalities. Biopsy of the sural nerve showed scattered axons with very thin myelin sheaths. There was also a nearly complete loss of large diameter myelinated fibers. No onion bulb formations were noted. These findings were thought to be consistent with congenital hypomyelination neuropathy with a component of axonopathy. DNA analysis for identification of previously characterized mutations in the genes MPZ, PMP22, and EGR2 was negative. Several attempts at extubation failed and the infant became increasingly ventilator-dependent with increasing episodes of desaturation and hypercapnea. He also developed increasing weakness and decreased movement of all extremities. He underwent surgery at 2 months of age for placement of a gastrostomy tube and a tracheostomy. He was discharged from the hospital on a ventilator at 6 months of age. The infant was 13 months old at the time of submission of this report. Although he appears cognitively normal, he remains profoundly hypotonic and is on a home ventilator. There was no evidence of progressive weakness. Congenital hypomyelination neuropathy is a rare form of neonatal neuropathy that should be considered in the differential diagnosis of a newborn with profound hypotonia and weakness. It appears to be a heterogeneous disorder with some of the cases being caused by specific genetic mutations. [source] CMT1A Associated With The 17p11.2 Duplication: Differential Features And CorrelationJOURNAL OF THE PERIPHERAL NERVOUS SYSTEM, Issue 1 2001D Pareyson A duplication on chromosome 17p11.2 encompassing the gene coding for the peripheral myelin protein-22 (PMP22) is the most common genetic abnormality underlying Charcot-Marie-Tooth disease (CMT). We report clinical and electrophysiologic features of our series of CMT1A patients harboring the duplication. There were 92 patients from 53 families representing 42% of all CMT index cases (n = 125) and 64% of CMT1 probands (n = 83). In CMT1A patients, mean age at onset was 9.7 ± 11.4 and was significantly lower than in non-duplicated CMT1 cases (12.6 ± 9.7, p < 0.01) and CMT2 cases (21.5 ± 17, p < 0.001). Clinical severity was similar to that of CMT2 patients, but significantly milder than in non-duplicated CMT1 cases. Pes cavus, upper limb involvement, deep tendon reflexes abnormalities, and sensory loss were more frequent compared to CMT2. Electrophysiologic examination revealed motor and sensory conduction velocity (MCV, SCV) slowing below 32 m/s in upper limbs. MCV and SCV were significantly lower than in non-duplicated CMT1 patients. Amplitudes of upper limb compound muscle action potentials (CMAPs) and of upper and lower limb sensory action potentials (SAPs) were significantly lower than in CMT2, paralleling clinical differences. Clinical severity correlated with CMAP amplitudes and with disease duration. On the other hand, MCV slowing was not correlated with either severity or duration of the disease. We found a direct correlation between age at onset and upper limb MCV slowing. Conclusions: CMT1A is an early-onset but slowly progressive disorder, on average milder than other CMT1. Axonal loss rather than demyelination per se underlies disease progression. [source] ELECTROPHYSIOLOGICAL ABNORMALITIES IN DIABETIC PATIENTSJOURNAL OF THE PERIPHERAL NERVOUS SYSTEM, Issue 1 2000B. Lanzillo We studied 476 patients affected by diabetes: 166 male (mean age 61.6 ± 10 years, range 27,91) and 310 female (mean age 61.5 ± 8.4 years, range 25,82). Mean disease duration was 11.3 ± 7.6 years, range 0.3,37). All patients underwent surface motor and sensory nerve conduction along median, popliteal, and sural nerve. Results. Median nerve: in 3.1% of subjects sensory action potentials (SAP) was absent; sensory nerve conduction velocity (SNCV) was reduced in 41.8% in distal segment and in 27.5% in the proximal segment. Motor nerve conduction (MNCV) was reduced in 29.9% of the subjects. Sural nerve: SAP was absent in 24.4% and SNCV was reduced in 32.7%. Popliteal nerve: MNCV was abnormal in 30.4% of the subjects. Combining electrophysiological data we observed that: 1. 28.6% of the subjects resulted normal 2. 12.8% were affected by a lower limbs sensory neuropathy 3. 0.2% had a lower limbs motor neuropathy 4. 5.9% had a lower limbs sensory-motor neuropathy 5. 6.1% had a diffused sensory neuropathy 6. 30.2% had a diffused sensory-motor neuropathy 7. 16.2% had a carpal tunnel syndrome. Patients were divided in 2 groups: patients with and patients without neuropahy: the latter showed a significantly shorter disease duration (12.7 ± 8.1 vs 9.0 ± 6.3; p < 0.0001). In addition, we observed a significant correlation between disease duration and distal latency, median and popliteal MNCV, and SNCV in median and sural nerve (Regression test; p < 0.0001). Patients on insulin showed a longer disease duration and more severe electrophysiological abnormalities. [source] Sensory potentials evoked by tactile stimulation of different indentation velocities at the finger and palmMUSCLE AND NERVE, Issue 9 2001Masayuki Baba MD Abstract Previous studies suggest that the rate of indentation of a tactile probe determines which skin mechanoreceptors are activated. To further investigate this possibility, indentations of 300 ,m at velocities of 100 (T100) and 400 ,m/ms (T400) were applied to the tip (FT) and the proximal phalanx of digit III (PP) and the thenar eminence (Pm) of ten healthy volunteers, and compared with responses after electrical stimulation at the FT. Compound sensory action potentials (CSAPs) were recorded from the median nerve through needle electrodes at the wrist and elbow. The maximal sensory conduction velocities (SNCVs) between wrist and elbow were similar with electrical and T400 stimulation, but on average were 15% lower with T100 stimulation (P < 0.001). With both indentation velocities, SNCVs were similar regardless of stimulation sites. Amplitudes of tactile CSAPs with FT stimulation were 1,2 ,V at T400 and 0.3,0.4 ,V at T100. The CSAP areas evoked by T100 stimulation showed a reduction from fingertip to proximal finger to palm (P < 0.05,0.005), whereas those obtained with T400 stimulation showed a reduction only at the palm (P < 0.05). The results support previous studies indicating that fast indentation at 400 ,m/ms activated deeply placed Pacinian corpuscles as well as superficially situated Meissner corpuscles, whereas slower indentation at 100 ,m/ms activated primarily Meissner corpuscles. © 2001 John Wiley & Sons, Inc. Muscle Nerve 24: 1213,1218, 2001 [source] Status 5 Years after Bilateral Hand TransplantationAMERICAN JOURNAL OF TRANSPLANTATION, Issue 4 2006S. Schneeberger Graft survival and function early after hand transplantation is good. It remains unknown, however, whether long-term survival is limited by chronic rejection. We here describe the clinical course and the status 5 years after bilateral hand transplantation with emphasis on immunosuppression (IS), function, morphology and graft vascular changes. Clinical observation, evaluation of hand function, skin biopsies, X-ray, ultrasound, angiography, CT angiography, electrophysiologic studies including compound motor and sensory action potentials (CMAP, CSAP) and somatosensory evoked potentials were performed and results recorded at regular intervals. Following reduction of IS one mild (grade II) rejection episode occurred at 4 years. Subsequently, skin histology remained normal and without signs of chronic rejection. Hand function continuously improved during the first 3 years and remained stable with minor improvement thereafter. CMAP and CSAP progressively increased during the observation period. Latencies of the cortical responses were prolonged but amplitudes were within normal range. Investigation of hand vessels revealed no signs of occlusion but showed revascularization of a primarily occluded right radialis artery. Motor and sensory function improved profoundly between years 1 and 5 after hand transplantation. No signs whatsoever of chronic rejection have been observed. [source] | ||||||||||