Using the emerging technique of peripheral nerve ultrasonography, multiple focal nerve swellings corresponding to sites of existing conduction blocks have been described in demyelinating polyneuropathies. We report two cases of multifocal acquired demyelinating sensory and motor neuropathy (MADSAM). In the first, multiple focal nerve enlargements were detected by ultrasound at sites of previous...

Cochlear implants are used to restore hearing in the profoundly deaf [Th.J. Balkany, Otolaryngol. Clin. North. Am. 19 (2) (1986) 215-449] by direct electrical stimulation of the auditory nerve. To study the working mechanism of cochlear implants and to provide a tool to develop better ones, a Boundary Element electrical volume conduction model of the cochlea (the auditory part of the inner ear)...

A 73-year-old man developed a fulminant form of Guillain-Barrd syndrome with abolition of brainstem reflexes. Antibodies to GQ1b were positive (1:180). The clinical findings mimicked a "brain death" pattern for a period of 12 days. In contrast, the EEG showed remaining cerebral electrical activity. Brainstem auditory evoked potentials, long-latency auditory potentials and flash-evoked visual po...

A reversible nerve-blocking spin label, 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) was used to study the nature of anesthetic-binding sites in nerve membranes as a function of pressure. The nerve-blocking effect of TEMPO is enhanced under pressure. At atmospheric pressure, TEMPO blocks nerve conduction by solubilizing in the apolar region of the nerve membrane. However, the nerve-conduction-b...

The frequency-following response (FFR) is a measure of the brain's periodic sound encoding. It is of increasing importance for studying the human auditory nervous system due to numerous associations with auditory cognition and dysfunction. Although the FFR is widely interpreted as originating from brainstem nuclei, a recent study using MEG suggested that there is also a right-lateralized contri...

Mercury is known to alter neuronal function and has been shown to cross the placental barrier. These experiments were undertaken to examine if gestational exposure to mercury vapor (Hg(0)) would result in alterations in sensory neuronal function in adult offspring. Dams were exposed to 0 or 4 mg/m(3) Hg(0) for 2 h/day from gestational days 6-15. This exposure paradigm has been shown to approxim...

Acute axonal polyneuropathy and Wernicke-Korsakoff encephalopathy developed simultaneously in three patients. Nerve conduction studies (NCS) detected markedly decreased compound muscle action potentials (CMAPs) and sensory nerve action potentials (SNAPs) with minimal conduction slowing; sympathetic skin responses (SSRs) were also notably decreased. Sural nerve biopsies showed only mild axonal d...

A pontine hemorrhage can evoke several neurological symptoms because the pons contains various nuclei and nerve fibers. Hearing loss can develop as a result of a pontine hemorrhage because there is an auditory conduction pathway in the cochlear nucleus of the pons. However, very few cases of hearing loss caused by pontine lesions have been reported, and there have been no reports of auditory ne...

BACKGROUND The rapid spread of devices generating electromagnetic fields (EMF) has raised concerns as to the possible effects of this technology on humans. The auditory system is the neural organ most frequently and directly exposed to electromagnetic activity owing to the daily use of mobile phones. In recent publications, a possible correlation between mobile phone usage and central nervous s...

Direct stimulation of 23 median, 13 ulnar and 2 peroneal nerves at the time of surgical exploration has been used to locate, and characterize the conduction abnormalities in the nerves. The most frequent location of the major conduction abnormalities in the median nerve was in the first 1-2 cm distal to the origin of the carpal tunnel. In the ulnar nerve the important conduction abnormalities w...