Somatosensory evoked potentials.

Somatosensory evoked potentials (SEPs) have been routinely used over the years to evaluate the somatosensory pathway and thereby supplement the diagnostic process when the history, neurologic examination, and imaging were not fully conclusive. The utilization of SEPs has become more popular in recent years despite the advance of imaging studies such as magnetic resonance imaging (MRI). Although no agreement has been found on the nomenclature and origins of some of the potentials, the most consistently recognized potentials have been used in clinical practice with montages and normative values set by each individual laboratory. The clinical use of SEPs will probably continue to increase as diagnostic and prognostic markers of central and peripheral nervous system disorders and in clinical trials.

Electrophysiology of Cranial Nerve Testing: Trigeminal and Facial Nerves.

The clinical examination of the trigeminal and facial nerves provides significant diagnostic value, especially in the localization of lesions in disorders affecting the central and/or peripheral nervous system. The electrodiagnostic evaluation of these nerves and their pathways adds further accuracy and reliability to the diagnostic investigation and the localization process, especially when different testing methods are combined based on the clinical presentation and the electrophysiological findings. The diagnostic uniqueness of the trigeminal and facial nerves is their connectivity and their coparticipation in reflexes commonly used in clinical practice, namely the blink and corneal reflexes. The other reflexes used in the diagnostic process and lesion localization are very nerve specific and add more diagnostic yield to the workup of certain disorders of the nervous system. This article provides a review of commonly used electrodiagnostic studies and techniques in the evaluation and lesion localization of cranial nerves V and VII.

CNS intravascular lymphoma: a case report.

Intravascular lymphoma is a rare but well-described entity. The clinical manifestations are heterogeneous. We report a case of a 59-year-old woman who presented initially with syncope followed by subacute cognitive decline that progressed to minimally conscious state. Shortly after the transfer to our tertiary center the patient died. Brain autopsy disclosed the diagnosis of B-cell intravascular lymphoma. We speculate that syncope could be the first manifestation of central nervous system intravascular lymphoma and should be considered in the differential diagnosis of unexplained syncope. In addition, we stress the importance of early brain biopsy in unexplained white matter disease.

Anti-glutamic Acid decarboxylase antibody-associated ataxia as an extrahepatic autoimmune manifestation of hepatitis C infection: a case report.

Extrahepatic immunological manifestations of hepatitis C virus (HCV) are well described. In addition, antiglutamic acid decarboxylase (GAD) antibody-associated cerebellar ataxia is well-established entity. However, there have been no reports in the literature of anti-GAD antibody-associated ataxia as an extrahepatic manifestation of HCV infection. We report the case of a young woman with chronic hepatitis C virus and multiple extrahepatic autoimmune diseases including Sjögren syndrome and pernicious anemia who presented with subacute midline cerebellar syndrome and was found to have positive antiglutamic acid decarboxylase (GAD) antibody in the serum and cerebrospinal fluid. An extensive diagnostic workup to rule out neoplastic growths was negative, suggesting the diagnosis of nonparaneoplastic antiglutamic acid decarboxylase antibody-associated cerebellar ataxia as an additional extrahepatic manifestation of hepatitis C virus infection. The patient failed to respond to high-dose steroids and intravenous immunoglobulin. Treatment with the monoclonal antibody rituximab stabilized the disease. We postulate that anti-GAD associated ataxia could be an extrahepatic manifestation of HCV infection.

Optic neuritis presenting with amaurosis fugax.

Optic neuritis usually presents with rapid and gradual loss of vision that is either complete or incomplete, and typically associated with retro-orbital pain. To our knowledge there have been no documented reports of optic neuritis presenting with multiple episodes of amaurosis fugax, the sudden and transient loss of vision lasting seconds to minutes. We report here the case of a young woman with a possible diagnosis of demyelinating left optic neuritis that presented solely with multiple episodes of brief and transient sudden loss of vision. Ophthalmological exams were normal between episodes of vision loss. The patient's magnetic resonance imaging of the brain showed a subtle enhancement of the left optic nerve along with multiple periventricular lesions, highly suggestive of a demyelinating disease. The frequent episodes of visual loss resolved completely with high dose parenteral steroids. Neurologists and other clinicians should be aware of this unusual presentation of optic neuritis as treatment modalities differ greatly from other causes of amaurosis fugax.