Evaluation of Nerve Conduction Studies in Obese Children With Insulin Resistance or Impaired Glucose Tolerance.

The aim of the study was to investigate nerve conduction studies in terms of neuropathic characteristics in obese patients who were in prediabetes stage and also to determine the abnormal findings. The study included 69 obese adolescent patients between April 2009 and December 2010. All patients and control group underwent motor (median, ulnar, tibial, and peroneal) and sensory (median, ulnar, sural, and medial plantar) nerve conduction studies and sympathetic skin response test. Sensory response amplitude of the medial plantar nerve was significantly lower in the patients with impaired glucose tolerance and insulin resistance. To our knowledge, the present study is the first study demonstrating the development of sensory and autonomic neuropathy due to metabolic complications of obesity in adolescent children even in the period without development of diabetes mellitus. We recommend that routine electrophysiological examinations be performed, using medial plantar nerve conduction studies and sympathetic skin response test.

Clinical and electrophysiologic findings in dialysis patients.

The aim of this study was to quantitatively determine the electrophysiologic changes occurring in the peripheral nerves and muscles in patients with chronic renal failure (CRF) treated with haemodialysis (HD) or continuous ambulatory peritoneal dialysis (CAPD), and to determine which electrophysiologic parameters are most commonly abnormal in uraemic patients. We investigated the relationship between the parameters of neurography and quantitative electromyography (QEMG) and clinical findings. The study included 42 patients with CRF (30 on HD and 12 on CAPD). Nerve conduction studies (NCSs) of the median, ulnar, tibial, peroneal, and sural nerves, and QEMG of the tibialis anterior and biceps brachii muscles were performed. We found axonal and/or demyelinating polyneuropathies in 97.6% of the patients (100% of HD and 91.7% of CAPD patients), but were not able to verify any significant differences between the HD and CAPD patients using NCS or QEMG. Median, ulnar, sural sensory nerve action potential (SNAP) amplitudes, peroneal CV and F-latency were the most common abnormal parameters in sensory and motor NCSs, respectively. The clinical findings only correlated with the parameters of neurography, and not with the parameters of QEMG. Sural SNAP amplitudes, peroneal and tibial CVs, F-latencies also correlated with the severity of the clinical findings in these patients, suggesting that these parameters can be used in follow up studies in these patients. In this study, most of the uraemic patients were found to have already mild or moderate neuropathies in which the objective clinical signs might be absent, even if they have some clinical symptoms. NCS showed abnormality indicating polyneuropathy in 24 out of 25 patients with clinical neuropathy signs and in 17 out of 17 patients with no clinical signs. Thus, in subclinical conditions NCS is useful to detect the abnormalities in peripheral nerves of the ureamic patients under chronic dialysis.

Sympathetic skin response and axon count in carpal tunnel syndrome.

The aim of this study was to determine the sensitivity of sympathetic skin response (SSR) in evaluating autonomic involvement in carpal tunnel syndrome (CTS) while simultaneously showing the axonal loss by motor unit number estimation (MUNE). Bilateral SSR were recorded by suprasternal stimulus in 50 hands of 31 patients and compared with 50 hands of 25 healthy volunteers. The groups were examined for sympathetic symptoms and sympathetic symptom scores (SSS) were determined. Axon count was performed on the abductor pollicis brevis (APB) muscle by using the MUNE method (with incremental technique) in both groups. There was no SSR difference between groups, although a significant difference was found for SSS. No relationships were found between SSR parameters and SSS or the electrophysiologic stage. MUNE of the APB muscle was significantly lower in CTS group and there was a negative correlation between MUNE and the electrophysiologic stage. The comparison of the MUNE and the amplitude of median compound muscle action potential indicated that MUNE is a highly sensitive method of determining severity in patients with CTS. In evaluating autonomic involvement in CTS, SSR does not seem to be a sensitive method. MUNE is a good indicator of motor reserve and can be helpful when following the treatment and prognosis of CTS in clinical practice.

Ultrasonography in carpal tunnel syndrome: comparison with electrophysiological stage and motor unit number estimate.

The purpose of this study was to document the ultrasonographic measurement differences in median nerve size between patients with carpal tunnel syndrome (CTS) and controls, and to correlate these findings with electrophysiological stage and motor unit number estimation (MUNE), thereby allowing us to test the validity of ultrasound as a diagnostic modality for assessing the severity of CTS. High-resolution sonography and electrophysiological studies were performed on 41 wrists of 27 patients and compared with findings on 40 wrists of 20 healthy individuals. On ultrasonographic views, cross-sectional area and flattening ratio in proximal, middle, and distal tunnel segments of the median nerve were measured both by calculating ellipsoid area by large and small cross-sectional diameters and by automated ellipsoid area calculation. We compared electrophysiological stage and MUNE with proximal, middle, and distal cross-sectional area and other ultrasonographic findings. All correlations between electrophysiological stage and cross-sectional areas in these different segments of the median nerve were significant with both measurement methods. Negative correlations were seen between MUNE and cross-sectional area in the proximal and middle segments, whereas no significant correlation was detected in the distal segment. Our results indicate that there are close correlations between the ultrasonographic findings and electrophysiological stage. Ultrasound also reflects the reduction in the number of axons estimated by the MUNE method. Therefore, we suggest that the ultrasonographic findings reflect the severity of disease in patients with CTS.

A case of bilateral simultaneous sixth cranial nerve palsies secondary to diabetes mellitus.

Ocular motor cranial nerve palsy secondary to diabetes mellitus usually affects one cranial nerve at a time. We report a patient with simultaneous bilateral sixth nerve palsies attributed to diabetes. Although an extremely rare cause of this phenomenon, diabetes may be the explanation after other causes have been excluded.

Effect of heating on nerve conduction in carpal tunnel syndrome.

The effect of temperature on normal nerves is well known, i.e., an increase in conduction velocity and a decrease in amplitude with an elevation in temperature. There are few reports examining the effect of temperature on abnormal nerves, e.g., in demyelination. To study the effect of increased temperature on demyelinating nerves in entrapment syndromes, the authors investigated 55 median and 48 ulnar nerves of 48 patients with carpal tunnel syndrome, and 48 median and 48 ulnar nerves of 26 healthy subjects. All measurements were obtained at 32 degrees C and 37 degrees C. Mean reductions in median sensory amplitude occurring with heating were significantly greater in the patient group than in the control group (P = 0.000). For median sensory response amplitude, the mean decrease was 32.1% in patients with carpal tunnel syndrome and 10.7% in the control subjects. The difference between median and ulnar nerves in the latency was significantly decreased (P = 0.027) after the nerves had heated to 37 degrees C. It is concluded that the elevation in temperature leads to conduction block in demyelinated sensory nerves, and that temperature provocation may be useful in the diagnosis of nerve disorders. The effect may be different in axonal and demyelinating disorders.

Effects of haemodialysis and continuous ambulatory peritoneal dialysis on P300 cognitive potentials in uraemic patients.

The aim of this study was to determine the effects of haemodialysis (HD) and continuous ambulatory peritoneal dialysis (CAPD) on P300 cognitive potentials in patients with chronic renal failure (CRF) and to find out if P300 potential is a valuable marker for following subclinical cognitive disorder. This study was performed in 42 patients with chronic uraemia, of whom 25 were on HD and 17 on CAPD, and in 25 healthy subjects. All the subjects were investigated in terms of P300 cognitive potential obtained from auditory stimuli with the oddball paradigm and the Mini-Mental State (MMS) examination. Patients undergoing HD were evaluated before (pre-dialysis) and after (post-dialysis) standard HD treatment. P300 latency was longer in HD patients than in the control group and CAPD patients. The MMS score was greater and P300 latency was shorter after a standard HD session when compared to pre-dialysis values in HD patients (p < 0.001 for both values). There was a negative correlation between P300 latency and MMS scores, and a positive correlation between P300 amplitude and MMS scores. In conclusion, P300 is useful for evaluating cognitive function in uraemia, even in asymptomatic patients, and CAPD is superior to HD in the management of cognitive impairment.

Bilateral neurogenic thoracic outlet syndrome.

We report a case of bilateral neurogenic thoracic outlet syndrome (TOS). Electrophysiological examination suggested the presence of bilateral lower brachial plexus neuropathy. Radiography showed rudimentary bilateral cervical ribs. In the cases reported in the literature to date, the clinical findings are typically unilateral despite the common presence of bilateral bony abnormalities. Neurogenic TOS should be considered in young women, even if they present with bilateral symptoms, when they have occupations requiring strenuous activity of the upper limbs.