The generalizability of neurocognitive test/retest data derived from a nonclinical sample for detecting change among two HIV+ cohorts

Objective methods for determining clinically relevant neurocognitive change are useful for clinicians and researchers, but the utility of such methods requires validation studies in order to assess their accuracy among target populations. We examined the generalizability of regression equations and reliable change indexes (RCI) derived from a healthy sample to two HIV-infected samples, one similar in demographic makeup to the normative group and the other dissimilar. Measures administered at baseline and follow-up included the Trail Making Test, Controlled Oral Word Association Test (COWAT), Grooved Pegboard, and Digit Span. Frequencies of decline, improvement, or stability were determined for each measure. Among the demographically similar clinical cohort, elevated rates of decline among more immunologically impaired participants were indicated by simple regression method on measures of psychomotor speed and attention, while RCI addressing practice effects (RCI-PE) indicated improvement on most measures regardless of immunostatus. Conversely, among the demographically dissimilar cohort, simple regression indicated high rates of decline across all measures, while RCI-PE indicated elevated rates of decline on psychomotor and attention measures. Thus, the accuracy of the two methods examined for determining clinically significant change among HIV+ cohorts differs depending upon their similarity with the normative sample.     

Reversible Cerebral Vasoconstriction Syndrome Associated with Subarachnoid Hemorrhage

Introduction  

Reversible cerebral vasoconstriction syndrome (RCVS) is a rare vasculopathy of unknown etiology. Ischemic stroke and intracerebral hemorrhage are well-documented sequelae, but subarachnoid hemorrhage is an uncommon complication of RCVS.     

Altitude training for the marathon

For nearly 40 years, scientists and elite endurance athletes have been investigating the use of altitude in an effort to enhance exercise performance. While the results of many early studies on the use of altitude training for sea level performance enhancement have produced equivocal results, newer studies using the 'live high, train low' altitude training model have demonstrated significant improvements in red cell mass, maximal oxygen uptake, oxygen uptake at ventilatory threshold, and 3000m and 5000m race time. For the marathoner looking to add altitude training to their peak performance plans, residence at an altitude of 2000-2500m, a minimum of 20 hours per day, for 4 weeks, appears to hold the greatest potential for performance enhancement.Based on published mathematical models of marathon performance, a marathoner with a typical or average running economy who performed 'live high, train low' altitude training could experience an improvement of nearly 8.5 minutes (or approximately 5%) over the 26.2-mile race distance.