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Background Oxaliplatin is an effective drug used mainly for advanced colorectal cancer. Neurotoxicity is the major side effect of oxaliplatin. The present clinical and neurophysiologic study was conducted to evaluate patients receiving oxaliplatin therapy. Patients and Methods Thirty-one consecutive patients with colorectal cancer who received oxaliplatin therapy were followed up for more than 3 years. The patients underwent clinical and neurophysiologic tests for large and small fiber function at every visit. Results Most of the patients received oxaliplatin-based chemotherapy at the initial dose of 130 mg/m2 for 6 to 8 cycles, normally every 3 weeks. Acute neurotoxicity with cold and mechanical hyperalgesia was reported by the vast majority of patients after each cycle of therapy and was confirmed by the quantitative sensory, filament, and axon reflex test. Chronic sensory cumulative neuropathy developed in most of the patients after the middle of therapy with numbness and was assessed using clinical scales, nerve conduction studies, and the vibration threshold. Our results support the persistence of the sensory nerve deficits for years after cessation of oxaliplatin therapy. Conclusion Our study has confirmed the results of a few previous long-term studies concerning the persistence of chronic large sensory fiber neuropathy and the influence of the cumulative dose of oxaliplatin on the development and severity of the chronic neuropathy. Our findings have improved the knowledge about the acute oxaliplatin-induced neurotoxicity using the C-fiber axon reflex response.

To investigate the underlying mechanisms of polyneuropathy induced by HIV infection or antiretroviral drugs.We tested 100 HIV patients (59 with AIDS). Ninety-three patients received antiretroviral drugs. Forty-four were treated with neurotoxic compounds (ddI, ddC, d4T). Nerve conduction velocities and the sympathetic skin response (SSR) in palms and soles were measured in all patients. In skin biopsies (ankle and thigh), the intraepidermal nerve fiber density (IENFD) and the number of epidermal fibers without contact to the basal membrane (fragments) were quantified using PGP9.5 staining.Severity of the disease (CD4 +count) correlated to conduction velocities of peroneal (p0.01, Spearmans rank correlation), sural (p0.01) and median nerves (p0.05/p0.001, sensory/motor). In contrast, the duration of neurotoxic treatment did not impair conduction velocities (p0.3) but correlated to reduced IENFD in the ankle (r = -0.24, p0.05). Despite their reduced IENFD, patients with long neurotoxic treatment had a high number of fragments irrespective of their CD4 +count.Neurotoxic treatment appears to primarily impair thin fiber conduction, whereas HIV neuropathy is linked to large fiber impairment and reduction of fragments of nerve fibers.These findings emphasize the differential pattern of polyneuropathy in HIV patients caused by the infection or induced by antiretroviral treatment.

Objectives Mirror movements (MMs) are unintended and unnecessary movements accompanying voluntary activity in homologous muscles on the opposite side of the body, particularly in distal arm muscles. Congenital MMs may be sporadic or familial. Several mechanisms have been proposed to explain persistent congenital MMs. Hypothesis 1 assumes the existence of an ipsilateral corticospinal pathway, and Hypothesis 2 the activation of both motor cortices. We report a new case of congenital mirror movements in a healthy woman. Methods Electromyographic recordings and focal transcranial magnetic stimulation (TMS) were used for neurophysiological evaluation. Results Voluntary contraction of either abductor pollicis brevis (APB) elicited mirror activation of the other APB. Focal TMS of either M1 elicited motor evoked potential (MEP) of normal latency and amplitude in both resting APB. TMS of the left cortex upon maximal contraction of the right APB and mirror contraction of the left APB produced interhemispheric inhibition (IHI) in the former and silent period (SP) in the later. Conclusions The electrophysiological evaluation using transcranial magnetic stimulation provides evidence of the concurrent action of both mechanisms in this patient. Significance The combination of more than one hypothesis could be more appropriate for understanding the underlying mechanism in some MM cases.

Summary Aims of the study To detect amplitude differences between the sensory nerve action potentials (SNAP) obtained by simultaneous recording of the two main branches of the superficial peroneal sensory nerve (SPSN), the medial and intermediate dorsal cutaneous sensory nerves (MDCN, IDCN); to investigate whether these differences, if any, are correlated with gender, age, body mass index (BMI), and height of normal subjects; to discuss their clinical significance. Population and methods Seventy-six healthy volunteers (36 males) were included (mean age: 36.5 years, range 20–80). Simultaneous MCND and IDCN recordings were performed via surface electrodes placed at precise positions on the intermalleolus line. Stimulation was performed 14 cm proximally on two different sites over the anterolateral aspect of the right leg. Results Responses were obtained for both nerve branches in all subjects. Median value and lower normal limit for the amplitude of the greater among both MDCN and IDCN responses was 10.95 μV and 4.9 μV, respectively. Statistically significant differences were found between the two branches in median amplitude and frequency of the greater value. These differences were not correlated with gender, age, BMI, or height. Conclusion We propose simultaneous recording of the two main branches of the superficial peroneal sensory nerve, placing the recording electrodes and stimulation device on precise positions and measuring the amplitude of the best of both responses. This method is an improvement of an already existent one, and may be clinically useful in detecting abnormal responses of the SPSN.

The study assessed HIV-related and anti-retroviral therapy-induced neuropathy in myelinated and unmyelinated nerve fibers. One hundred consecutive HIV patients were examined clinically and standard nerve conduction velocities were measured. In addition, electrically induced sympathetic skin response (SSR) was assessed in the palms and soles. The difference in delay of SSR in palms and soles (DeltaSSR) was calculated as an indirect measure of C-fiber conduction velocity. Thick fiber conduction velocities significantly decreased with age and increasing stage of the disease, whereas no effect of stage was found for DeltaSSR (p=0.6). In contrast, medication of at least one of the most known neurotoxic drugs zalcitabine, stavudine, or didanosine did not result in significantly lower conduction velocities in thick fibers (51.29+/-3.4 m/s vs. 50.86+/-3.5 m/s), but was related to an increased DeltaSSR. DeltaSSR allows an indirect measurement of C-fiber conduction velocity. In HIV this measure of unmyelinated sympathetic fibers was most sensitive to anti-viral treatment whereas conduction velocity of myelinated somatic fibers was more sensitive to disease-related neuropathy. The results suggest that HIV neuropathy preferably affects myelinated and anti-retroviral therapy unmyelinated fibers.

Objective To explore the presence and grade of denervation in three mimic muscles in facial nerve palsy. Methods The frontalis, orbicularis oculi (OO), and mentalis muscles were explored in 54 patients with Bell's palsy, after 30 days from the beginning of symptoms. Concentric needle electromyography, including fibrillation detection, was performed in the three muscles on the affected side. Compound muscle action potentials (CMAP) were recorded on both sides and a CMAP ratio was calculated from each muscle. The House–Brackman scale was used to assess the initial clinical evaluation and the follow-up until recovery. Results Fibrillation was recorded in 32 patients on the 30th day after the onset and was present in 100% of mentalis and in 90% of frontalis, but in only 34% of OO, a statistically significant difference. The grade of fibrillation in OO was also statistically lower from those in the other two muscles. The 32 patients were grouped according to the presence (A) or not (B) of fibrillation in OO. In group A, CMAP ratios (affected/normal side) did not differ significantly among the three muscles. However, in group B they were significantly greater in OO and frontalis than in mentalis. In between-group comparison, group B muscles had significantly higher CMAP ratios, lower degree of fibrillation, and better functional recovery. Conclusion In facial palsy, the presence and grade of fibrillation in OO are lower than in frontalis and mentalis muscles and prognosis is more favorable for the non-fibrillating OO group of patients.