The effect of stimulation technique on sympathetic skin responses in healthy subjects

The aim of this study was to collect normative data for sympathetic skin responses (SSR) elicited by electrical stimulus of the ipsilateral and contralateral peripheral nerves, and by magnetic stimulus of cervical cord. SSRs were measured at the mid-palm of both hands following electrical stimulation of the left median nerve at the wrist and magnetic stimulation at the neck in 40 healthy adult volunteers (mean age 52.2 ± 12.2 years, 19 males). The onset latency, peak latency, amplitude and area were estimated in “P” type responses (i.e., waveforms with a larger positive, compared to negative, component). SSR onset and peak latency were prolonged when the electrical stimulus was applied at the contralateral side (i.e., the SSR recorded in the right palm P < 0.001). The onset latency was similar on both sides during cervical magnetic stimulation. However, peak latency was faster on the left side (P < 0.03). Comparison of electrical and magnetic stimulation revealed that both the onset and peak latency were shorter with magnetic stimulation (P < 0.001). The latency of a SSR varies depending on what type of stimulation is used and where the stimulus is applied. Electrically generated SSRs have a longer delay and the delay is prolonged at the contralateral side. These factors should be taken into account when interpreting SSR data

Quantification In Neurology

There is a distinct shift of emphasis in clinical neurology in the last few decades. A few years ago, it was just sufficient for a clinician to precisely record history, document signs, establish diagnosis and write prescription. In the present context, there has been a significant intrusion of scientific culture in clinical practice. Several criteria have been proposed, refined and redefined to ascertain accurate diagnosis for many neurological disorders. Introduction of the concept of impairment, disability, handicap and quality of life has added new dimension to the measurement of health and disease and neurological disorders are no exception. "Best guess" treatment modalities are no more accepted and evidence based medicine has become an integral component of medical care. Traditional treatments need validation and new therapies require vigorous trials. Thus, proper quantification in neurology has become essential, both in practice and research methodology in neurology. While this aspect is widely acknowledged, there is a limited access to a comprehensive document pertaining to measurements in neurology. This following description is a critical appraisal of various measurements and also provides certain commonly used rating scales/scores in neurological practice

Hepatic myelopathy: A rare complication following extrahepatic portal vein occlusion and lienorenal shunt

A 19-year-old gentleman presented with slowly progressive spastic paraparesis, 2 years after the therapeutic lienorenal shunt for portal hypertension secondary to cirrhosis and portal vein occlusion. After 2 years of initial evaluation, the motor functions had not worsened further. He did not have any obvious clinical or EEG features of hepatic encephalopathy. Other causes for myelopathy were ruled out. Contribution of portal vein occlusion to portosystemic shunting has not been reported previously in patients with 'hepatic myelopathy.' This uncommon complication needs to be considered in patients with shunt surgery for relieving portal hypertension

Two Cases Of Cerebrotendinous Xanthomatosis And A Short Review Of Pathophysiology

Cerebrotendinous Xanthomatosis(CTX) is an uncommon autosomal recessive disorder in which there is accumulation of cholestanol in tissues such as lens, tendons and nervous system. It is clinically characterized by progressive neurological and neuropsychiatric dysfunction with ataxia, spasticity, and peripheral neuropathy, associated with bilateral premature cataracts, tendon xanthomas, premature atherosclerosis and pulmonary dysfunction. Deficiency of the mitochondrial enzyme sterol 27-hydroxylase (CYP27 gene) is implicated in the pathogenesis. Two cases of CTX with similar history in the siblings, are being reported. One of them had tendon swelling, cataract, polyneuropathy, low IQ, ataxia, pyramidal tract involvement with electrophysiological abnormalities in the form of demyelinating neuropathy in nerve conduction tests and prolonged N19 latency in somato sensory evoked potential (SSEP) studies. The second patient had tendon swelling, low IQ, cataract, polyneuropathy, ataxia, involuntary movements, pyramidal signs with evidence of demyelinating neuropathy. She improved partially with Chenodeoxycholic acid (CDCA) and simvastatin. Histopathology of the tendon swelling in both the cases revealed disruption of the fibrocollagenous bands of the tendon by masses of xanthomatous cells containing foamy cytoplasm amassed around cholesterol clefts and multinucleated giant cells. Accurate and early diagnosis is important because of the therapeutic potential

Remitting - Relapsing Polyneuropathy In Juvenile Metachromatic Leukodystrophy

A five-year-old girl manifested with acute relapsing polyradiculo-neuropathy. Elevated cerebrospinal fluid proteins, electro-physiological evidence of conduction block and remitting course suggested possible acquired demyelinating radiculoneuropathy. However, intellectual deterioration during follow up, evidence of extensive, symmetrical and periventricular demyelination on MRI of brain and metachromatic on sural nerve biopsy led to the diagnosis of metachromatic leukodystrophy (MLD). Inherited neuropathies such as MLD may occasionally present atypically in the early stages. Recognition of this variation has considerable therapeutic and prognostic significance