A neurophysiological study of large- and small-diameter nerve fibers in the hands of hemodialysis patients.

PURPOSE: Polyneuropathy in patients with advanced clinical kidney disease is a very disabling condition. The aim of this study was to evaluate neurophysiological abnormalities of large- and small-diameter nerve fibers in the hands of hemodialysis patients. METHODS: A total of 38 hemodialysis patients and 38 healthy control subjects underwent a conventional electrophysiological examination. The function of small nerve fibers was assessed using cutaneous silent period (CSP) measurement. RESULTS: Slower median nerve motor conduction velocities were recorded in patients with fistula (p < 0.0001) and without fistula (p < 0.001). Sensory median and ulnar nerve conduction velocities were slower in both patient groups compared with the control group (p = 0.001). Median sensory nerve action potential amplitudes were lower in patients with fistulas (p = 0.009) and without fistulas (p = 0.005) compared with the control group. Significantly prolonged F-wave latencies of the median (p = 0.002) and ulnar nerves (p = 0.023) in patients with fistulas hands were observed. In 12/38 (32 %) patients, the onset latencies of CSPs were significantly delayed (p = 0.001). There was an inverse correlation of ß2-microglobulin and decreased conduction velocities of the median nerves, while Kt/V was associated with improved sensory nerve conduction velocity of the median nerve. An inverse correlation between motor velocity of both nerves and hemodialysis duration was observed in the patient groups. CONCLUSIONS: The measurement of CSPs provides a useful method for assessing small nerve fibers. The role of A-delta fibers is often overlooked.

Gender Differences in Biochemical and Electroneurographic Parameters of Median and Ulnar Nerve.

INTRODUCTION: In this article are demonstrated differences in the aspects of the metabolic syndrome (MSy) between genders, as well as the association of MSy and neuropathy. THE AIM: The aim of our study was that in patients with newly discovered metabolic syndrome of both sexes make comparison of fasting blood glucose levels and after oral glucose tolerance test, as well as neurophysiological parameters of n.medianus and n.ulnaris. PATIENTS AND METHODS: All participants were examined dermatologically. The analysis included the 36 male and 36 female respondents with a newly discovered MSy. RESULTS: The average age of men was 52.75±7.5 (40-65) years and women 52.1±7.7 (38-67) years. The average value of fasting blood glucose in women was 5.86±0.87 (4.5-8) mmol/L, and non significantly higher in men (p=0.0969) as 6.19±0.8 (4.7-8) mmol/L. Average values of blood sugar 120 minutes after oral glucose tolerance test were not significantly different (p=0.7052), and was 5.41±1.63 (3.3-9.7) mmol/L in women and 5.27±1.52 (2.7-9.8) mmol/L in men. Median motor velocity were significantly higher in women for n.medianus on the left (p=0.0024), n.ulnaris on the left (p=0.0081) and n.ulnaris on the right side (p=0.0293), and the median motor terminal latency were significantly longer in n.ulnaris on the left (p=0.0349) and n.ulnaris on the right side (p=0.011). There was no significant difference in the sensory conductivity velocity in n.medianus and n.ulnaris between the groups, but the amplitude with the highest peak of the sensory response was significantly higher in n.medianus on the left (p=0.0269) and n.ulnaris on the left side (p=0.0009) in female patients. CONCLUSION: The results indicate that there are differences in neurophysiological parameters of the investigated nerves between the genders, and that tested nerve structures in the course of MSy are affected slightly more in men. There were no significant differences in skin changes between genders.

Cutaneous silent period in the assessment of small nerve fibers in patients on hemodialysis.

AIM: In hemodialysis patients renal disease may cause an impairment of central and peripheral nervous system. In most cases of the peripheral nervous system polyneuropathy is reported. The aim of this study was to evaluate the function of small A-delta nerve fibres, whose function is often overlooked. METHODS: The function of large diameter nerve fibers was performed by standard routine neurophysiological examination. Cutaneous silent period (CSP) was elicited by single electrical stimulations at the tip of digit II by the bipolar electrodes. The superficial electrodes were placed on the muscle belly of m. abductor pollicis brevis. The onset latency (L1) was recorded at the beginning of voluntary muscle activity suppression, the late latency (L2) at the start of new muscle activity. The difference between two latencies indicates the duration of CSP. RESULTS: The study included 38 consecutive patients (male/female - 21/17, median age 56.6±10.9 years) treated with hemodialysis (one month to 30 years) and 35 healthy subjects (male/female 23/17, age 47.4±10.1 years). The results of the conduction study demonstrated a significant prolongation of F-waves of the median and ulnar nerves, decreased motor and sensory velocities of both nervesin patients on hemodialysis (p less than 0.001). In patients with A-V fistulas a significant prolongation of the onset CSP latency L1 was obtained (p less than 0.001), whereas duration of CSP was not changed. CONCLUSION: In hemodialysis patients the significant impairment of small nerve fibers was recorded. The evaluation of small nerve fibers contributes to the assessment of the whole peripheral nerve function.

Cutaneous silent period in the evaluation of small nerve fibres.

INTRODUCTION: High intensity cutaneous stimulus transiently suppresses tonic voluntary muscle activity resulting in cutaneous silent period (CSP). AIM: The aim of our study was to evaluate the normal values of an onset latency L1, a late latency L2 and a duration of CSP after stimulating sensory fibres of the median nerve. MATERIAL AND METHODS: This prospective study was performed at the Neurology Department, Clinical Center of Sarajevo University in period from January 1st 2013 to December 1st 2013. In our study we examined 61 subjects. The group included our relatives, coworkers and friends. The informed consent from testing subjects was obtained. RESULTS: The origin of silent period is stimulation of small A-delta nerve fibres. The pre-synaptic or post-synaptic interruption of the electrical volley to motor neurons is discussed. Median values of muscle activity suppression in healthy female is 55.0 ms (45.0-74.0) and 59.0 ms (52.0-67) male subjects. There is a correlation between the onset latency L1 and the late L2 latency (p < 0.03). In the on-going study it seems that delay of L1 and shorter muscle activity suppression might provide a sign of small nerve fibres involvement. CONCLUSION: The use of CSP improves the value of neurophysiology examination.

Hyperlipidemia as a risk factor for persons in specific professions.

INTRODUCTION: The increase in lipid levels associated with other risk factors for the occurrence of ischemic heart disease and stroke is one of the most important health problems in the world. Risk for development of changes is greater for people of specific occupations such as police officers. MATERIAL AND METHODS: This prospective study included 300 police officers, 150 as experimental and 150 respondents as a control group. To both groups same methods have been applied: A detailed history, physical examination, complete laboratory evaluation, lipid electrophoresis targeted to hypercholesterolemia, ultrasound of the abdomen and Color Doppler of the neck vascular structures. The results obtained by statistical analysis of the data showed that there was a significant increase in levels of cholesterol and triglyceride levels in experimental compared to the control group. Ultrasound of the abdomen showed fatty infiltrated liver in 16% of respondents from the experimental and 2% of the respondents in the control group 2%. Color Doppler of the neck blood vessels in 14% of respondents from experimental group showed changes in blood vessels, which ranged from mild thickening of the intima of the vessel to a 50% decrease in circulation. For the control group, this percentage was 0.66%. Considering that this study involved young, active working population, hyperlipidemia becomes a bigger problem.

Somatosensory evoked potentials in children with brain ventricular dilatation.

AIM: To determine possible nerve conduction changes in the somatosensory pathway in children with brain ventricular dilatation and to estimate the relation between the ventricular size and somatosensory evoked potentials (SEP). METHODS: Twelve children with ventricular dilatation (frontal and occipital horn ratios >0.44) and 19 children without ventricular dilatation (control group), aged between 2 and 15 years, were included in the study. Somatosensory evoked responses to median nerve stimulation were recorded in both groups. Evoked potentials were recorded by silver/silver chloride cup electrodes from Erb's point in the supraclavicular fossa (wave N9), the cervical spine at the C7 vertebral prominence (wave N13), and the scalp above the contralateral sensory cortex at the point C3' or C4', 1 cm behind the C3 or C4 site in the standard 10-20 system (wave N19). Computed tomography scanning was performed to estimate ventricular dilatation. RESULTS: The conduction time of the central somatosensory pathway (N19-N13 interwave latency) was significantly longer in the children with ventricular dilatation than in the control group (P = 0.046). A statistically significant but weak correlation was found between the frontal and occipital horn ratio values and the N19-N13 interwave latencies in the subjects with enlarged ventricles (r = 0.579, P = 0.045). CONCLUSION: Ventricular dilatation is associated with prolonged conduction of the central part of the somatosensory pathway in children. Early detection and treatment of hydrocephalus could be useful in preventing long-term consequences of high intraventricular pressure.