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Background: Distal symmetric polyneuropathy (DSP) is the most common variety of neuropathy. Since the evaluation of this disorder is not standardized, the available literature was reviewed to provide evidence-based guidelines regarding the role of laboratory and genetic tests for the assessment of DSP., Methods: A literature review using MEDLINE, EMBASE, Science Citation Index and Current Contents was performed to identify the best evidence regarding the evaluation of polyneuropathy published between 1980 and March 2007. Articles were classified according to a four-tiered level of evidence scheme and recommendations were based upon the level of evidence., Results and Conclusions: 1. Screening laboratory tests may be considered for all patients with polyneuropathy (Level C). Those tests that provide the highest yield of abnormality are blood glucose, serum B12 with metabolites (methylmalonic acid with or without homocysteine) and serum protein immunofixation electrophoresis (Level C). If there is no definite evidence of diabetes mellitus by routine testing of blood glucose, testing for impaired glucose tolerance may be considered in distal symmetric sensory polyneuropathy (Level C). 2. Genetic testing is established as useful for the accurate diagnosis and classification of hereditary neuropathies (Level A). Genetic testing may be considered in patients with cryptogenic polyneuropathy who exhibit a hereditary neuropathy phenotype (Level C). Initial genetic testing should be guided by the clinical phenotype, inheritance pattern, and electrodiagnostic (EDX) features and should focus on the most common abnormalities which are CMT1A duplication/HNPP deletion, Cx32 (GJB1), and MFN2 mutation screening. There is insufficient evidence to determine the usefulness of routine genetic testing in patients with cryptogenic polyneuropathy who do not exhibit a hereditary neuropathy phenotype (Level U).

Background: Distal symmetric polyneuropathy (DSP) is the most common variety of neuropathy. Since the evaluation of this disorder is not standardized, the available literature was reviewed to provide evidence-based guidelines regarding the role of autonomic testing, nerve biopsy and skin biopsy for the assessment of polyneuropathy., Methods: A literature review using MEDLINE, EMBASE, Science Citation Index and Current Contents was performed to identify the best evidence regarding the evaluation of polyneuropathy published between 1980 and March 2007. Articles were classified according to a four-tiered level of evidence scheme and recommendations were based upon the level of evidence., Results and Conclusions: 1. Autonomic testing may be considered in the evaluation of patients with polyneuropathy to document autonomic nervous system dysfunction (Level B). Such testing should be considered especially for the evaluation of suspected autonomic neuropathy (Level B) and distal small fiber sensory polyneuropathy (SFSN) (Level C). A battery of validated tests is recommended to achieve the highest diagnostic accuracy (Level B). 2. Nerve biopsy is generally accepted as useful in the evaluation of certain neuropathies as in patients with suspected amyloid neuropathy, mononeuropathy multiplex due to vasculitis, or with atypical forms of chronic inflammatory demyelinating polyneuropathy (CIDP). However, the literature is insufficient to provide a recommendation regarding when a nerve biopsy may be useful in the evaluation of DSP (Level U). 3. Skin biopsy is a validated technique for determining intraepidermal nerve fiber (IENF) density and may be considered for the diagnosis of DSP, particularly SFSN (Level C). There is a need for additional prospective studies to define more exact guidelines for the evaluation of polyneuropathy.

Objective: To determine the sensitivity and specificity of superficial peroneal nerve (SPN)/peroneus brevis muscle (PBM) biopsy in a cohort of patients with suspected peripheral nerve vasculitis., Background: In patients with suspected vasculitic neuropathy, combined nerve and muscle biopsies have been advocated as a way to increase the diagnostic yield, but the sensitivity and specificity of this approach have not been evaluated. Pathologic predictors of biopsy-proven peripheral nerve vasculitis have also not been analyzed in a systematic fashion., Methods: The clinical, laboratory, and pathologic data for all patients undergoing SPN/PBM biopsy for possible vasculitis from 1986 through 1996 were analyzed. Biopsies were classified as positive, negative, or suspicious for vasculitis. Patients were then divided into vasculitis and nonvasculitis cohorts by final clinical diagnosis., Results: Of 70 SPN/PBM biopsies, 22 (30%) showed definite vasculitis; nerve was diagnostic in 90% (n = 20) and muscle in 50% (n = 11). Nerve biopsy had a higher yield than muscle in patients with nonsystemic vasculitic neuropathy (p = 0. 0047) but not in those with systemic vasculitis. The estimated sensitivity of a positive SPN/PBM biopsy for vasculitis was 60%. Considering biopsies either positive or suspicious for vasculitis increased the sensitivity to 86% with a corresponding specificity of 85%. Pathologic features associated with necrotizing vasculitis were muscle fiber necrosis/regeneration (relative risk 18.1; 95% CI 3.4 to 96.1), predominant axonal nerve pathology (>8.8; >1.0 to 77.4), Wallerian-like degeneration (5.6; 1.4 to 21.9), and asymmetric nerve fiber loss (4.6; 1.4 to 15.9)., Conclusions: These findings establish the yield, sensitivity, and specificity of SPN/PBM biopsy for diagnosing vasculitic neuropathy and validate the use of suggestive pathologic features for diagnosing cases lacking definite necrotizing vascular changes.

Inclusion body myositis, polymyositis, and dermatomyositis are three distinct categories of inflammatory myopathy. Some authorities commented on the selective early weakness of the volar forearm muscles, quadriceps, and ankle dorsiflexors in inclusion body myositis. The most important feature distinguishing inclusion body myositis from the other two inflammatory myopathies is the lack of responsiveness to immunosuppressive treatment. Although most patients with inclusion body myositis have characteristic muscle biopsy findings, some cannot be distinguished histologically early from polymyositis. Predicting responsiveness to immunosuppressive medications, independent of muscle histology, would be valuable to clinicians. We retrospectively reviewed the pattern of weakness and other clinical features of 46 patients newly diagnosed with either inclusion body myositis, polymyositis, or dermatomyositis. Asymmetrical muscle weakness with prominent wrist flexor, finger flexor, and knee extensor involvement was specific for inclusion body myositis and unresponsive polymyositis. Male sex, lower creatine kinase levels, slower rate of progression, and peripheral neuropathy were also more common in inclusion body myositis and unresponsive polymyositis than in responsive polymyositis and dermatomyositis patients. Repeat muscle biopsy in 2 patients in the unresponsive polymyositis group demonstrated histological features of inclusion body myositis. We suspect that patients with clinical features of inclusion body myositis but lacking histological confirmation may nonetheless have inclusion body myositis. Our study supports the recently proposed criteria for definite and possible inclusion body myositis.

Electroencephalography has traditionally been considered a useful adjunct to the clinical evaluation of headache. We performed a literature review to determine whether evidence supports the routine use of the electroencephalogram (EEG) for patients with headache. After excluding case reports, case series in which subjects were selected because of abnormal EEGs, abstracts with insufficient information for analysis, and reviews without original data, we found 40 articles describing EEG findings in headache patients. These articles dated from 1941 to 1994. We compared these articles against six criteria established to determine the validity of data evaluating the utility of a diagnostic test. These criteria were (1) a comparison against established diagnostic criteria, (2) the use of appropriately matched controls, (3) a study setting that minimizes biases, (4) a blinded interpretation of the EEGs, (5) a sensible interpretation of the abnormalities observed, and (6) the replicability of the techniques used. One article met all six literature criteria, three articles met five criteria, 11 met four, nine met three, seven met two, seven met one, and two met none. The only abnormality consistently reported in headache patients, as opposed to controls, in studies of relatively nonflawed design was a prominent photic driving response at high flash (the "H-response"). The H-response was less effective than clinical criteria in distinguishing patients with headaches from individuals without headaches and in distinguishing migraine from other headache types. Studies did not show that the EEG is an effective screen for structural causes of headache, nor does the EEG effectively identify headache subgroups with different prognoses.(ABSTRACT TRUNCATED AT 250 WORDS)

Objective: In individuals who were infected with the human immunodeficiency virus (HIV) we determined the prevalence of peripheral neuropathies (PNs) and explored the relationship between immunologic competence and nerve function., Design: Cohort survey., Setting: US Air Force medical center., Patients: Population based. Seven hundred ninety-eight of 817 HIV-positive personnel identified by US Air Force HIV screening program from 1985 to 1989. Average age of cohort was 29.2 years. The majority were male with early-stage HIV disease., Main Outcome Measures: Neurologists examined all subjects for symptoms and signs of PN. We grouped patients by CD4 T-lymphocyte count. We further studied 300 HIV-infected volunteers without clinical evidene of PN by nervex

From 1958 to 1986, 27 crewmembers with suspected sleep disorders were referred to the USAF School of Aerospace Medicine. The presenting complaint in most cases was excessive daytime sleepiness (EDS). Prior to 1984, evaluations included neurologic and psychiatric testing, screening laboratory studies, and awake and asleep electroencephalography. Polysomnography and sleep latency studies were included after 1984. In the majority of cases, the etiology of the complaint could not be determined. The prevalence of EDS is estimated to be between 0.3% and 4.0% of the adult population. Major causes cited in the world literature include the sleep apnea syndromes, narcolepsy, parasomnias interrupting sleep, hypersomnia secondary to systemic or affective disorders, and essential hypersomnia. Current sleep lab techniques and human leukocyte antigen (HLA) typing are reported to make the diagnosis in up to 90% of sleep disorders. Evaluation of EDS should begin with a history emphasizing sleep habits, work schedules, daytime naps, and presence of vegetative signs. A sleep diary will allow a more accurate estimate of the quantity of nocturnal sleep. This diary may reveal poor sleep hygiene or insomnia. Polysomnography and/or multiple sleep latency determination can then be used to diagnose sleep apnea, parasomnias, and narcolepsy.