Appropriateness of Applying Cerebrospinal Fluid Biomarker Cutoffs from Alzheimer's Disease to Parkinson's Disease.

Background: While cutoffs for abnormal levels of the cerebrospinal fluid (CSF) biomarkers amyloid-β 1-42 (Aβ142), total tau (t-tau), phosphorylated tau (p-tau), and the ratios of t-tau/Aβ142 and p-tau/Aβ142, have been established in Alzheimer's disease (AD), biologically relevant cutoffs have not been studied extensively in Parkinson's disease (PD).

Objective: Assess the suitability and diagnostic accuracy of established AD-derived CSF biomarker cutoffs in the PD population.

Methods: Baseline and longitudinal data on CSF biomarkers, cognitive diagnoses, and PET amyloid imaging in 423 newly diagnosed patients with PD from the Parkinson's Progression Markers Initiative (PPMI) cohort were used to evaluate established AD biomarker cutoffs compared with optimal cutoffs derived from the PPMI cohort.

Posterior subscapular approach to the brachial plexus. Report of 102 patients.

A 15-year operative experience with 105 posterior subscapular approaches to the brachial plexus in 102 patients is presented. The procedure is indicated in carefully selected cases, especially where the proximal portions of lower spinal nerves are involved. Its main advantage is proximal exposure of the plexus spinal nerves, particularly at an intraforaminal level.

Neurologic recovery in quadriplegia following operative treatment.

Records and radiographs of 90 patients suffering complete or motor-complete quadriplegia and treated surgically were reviewed. There were 76 men or boys and 14 women or girls; ages ranged from 15 to 75. Eighty-one were complete quadriplegics and nine had some degree of sensory preservation.