Using and interpreting electrodiagnostic tests.

Electrodiagnostic testing, consisting of nerve conduction studies and needle electrode examination, serves as an extension of a neurologic examination for evaluating a variety of focal and generalized neuromuscular conditions. By providing important clues on location, chronicity, severity, and pathophysiology, it can help to establish a diagnosis, evaluate the need for surgery, and assess patients who do not improve as expected after surgery.

Utility of electrodiagnostic studies in patients referred with a diagnosis of polyneuropathy.

BACKGROUND: Peripheral polyneuropathies (PN) are common neuromuscular conditions. The role of electrodiagnostic study (EDX) in diagnosis of PN is not well-defined. METHODS: We performed a retrospective chart review of patients referred for EDX evaluation of PN. RESULTS: Of 162 patients analyzed, 23 had pure peripheral neuropathy (pPN; 14.2%), 29 had peripheral neuropathy and another diagnosis (PN+; 17.9%), 51 had an alternative diagnosis (nonPN; 31.5%), and 59 had normal studies (36.4%). In univariable analysis, age (P < .001) and gender (P = .004) were weakly associated with final diagnosis. In multinomial logistic regression analysis, significant predictors included age (odds ratio [OR] for nonPN/PN+:1.07 per year; 95% confidence interval [CI], 1.03-1.11), gender (OR for PN+:0.2, 95% CI, 0.07-0.61), and diabetes/prediabetes (OR for pPN:3.29; 95% CI, 1.17-9.27). CONCLUSIONS: These data suggest that EDX commonly yields additional or nonPNs in patients referred with a diagnosis of PN, and although some variables predict electrodiagnosis, none have a large enough effect to suggest poor utility in any subpopulation.

Patterning of regional gene expression in autism: new complexity.

Autism is a common and often severe neurodevelopmental disorder for which diverse pathophysiological processes have been proposed. Recent gene expression data comparing autistic and control brains suggest that the normal differential gene expression between frontal and temporal cortex is attenuated in autistic brains. It is unknown if regional de-differentiation occurs elsewhere in autistic brain. Using high resolution, genome-wide RNA expression microarrays and brain specimens meeting stringent selection criteria we evaluated gene expression data of two other regions: Brodmann area 19 (occipital cortex) and cerebellar cortex. In contrast to frontal/temporal cortical data, our data do not indicate an attenuation of regional specialization between occipital and cerebellar cortical regions in autistic brains.

Long-term effects of deep brain stimulation for essential tremor with subjective and objective quantification via mailed-in questionnaires.

BACKGROUND: Deep brain stimulation (DBS) is a standard treatment for patients with disabling essential tremor. The short-term efficacy rate is well established. OBJECTIVES: To assess the long-term effects of DBS in our series and evaluate the durability of the effects over time. METHODS: Eighty-four patients implanted with unilateral or bilateral DBS for essential tremor were asked to complete three mailed-in questionnaires to assess DBS efficacy objectively and subjectively. RESULTS: Twenty-six patients responded, with a median follow-up of 41 months. Approximately half of the patients had more than 48 months of follow-up. At the time of follow-up, the Tremor Rating Scale was reduced from a mean score of 7 (5-8) to 3 (2-3) with DBS OFF and ON, respectively. Quality of life, measured with a subset of items of the ADL Taxonomy, improved from a mean of 26 (23-33) to 12 (12-14), comparing DBS OFF and ON. No significant differences were seen when comparing efficacy at short- (<12 months), middle- (12-48 months) or long-term (>48 months) follow-ups. CONCLUSION: DBS has long-term efficacy for tremor control. This is associated with sustained benefits in quality of life. The duration of the follow-up was not associated with any significant difference in efficacy.

Brain transcriptional and epigenetic associations with autism.

BACKGROUND: Autism is a common neurodevelopmental syndrome. Numerous rare genetic etiologies are reported; most cases are idiopathic. METHODOLOGY/PRINCIPAL FINDINGS: To uncover important gene dysregulation in autism we analyzed carefully selected idiopathic autistic and control cerebellar and BA19 (occipital) brain tissues using high resolution whole genome gene expression and whole genome DNA methylation microarrays. No changes in DNA methylation were identified in autistic brain but gene expression abnormalities in two areas of metabolism were apparent: down-regulation of genes of mitochondrial oxidative phosphorylation and of protein translation. We also found associations between specific behavioral domains of autism and specific brain gene expression modules related to myelin/myelination, inflammation/immune response and purinergic signaling. CONCLUSIONS/SIGNIFICANCE: This work highlights two largely unrecognized molecular pathophysiological themes in autism and suggests differing molecular bases for autism behavioral endophenotypes.