Is it time to rethink how neuropsychological tests are used to diagnose mild forms of HIV-associated neurocognitive disorders? Impact of false-positive rates on prevalence and power.

BACKGROUND: Between 0 and 48% of normal HIV-uninfected individuals score below threshold neuropsychological test scores for HIV-associated neurocognitive disorders (HAND) or are false positives. There has been little effort to understand the effect of varied interpretations of research criteria for HAND on false-positive frequencies, prevalence and analytic estimates. METHODS: The proportion of normal individuals scoring below Z score thresholds drawn from research criteria for HAND, or false-positive frequencies, was estimated in a normal Kenyan population and a simulated normal population using varied interpretations of research criteria for HAND. We calculated the impact of false-positive frequencies on prevalence estimates and statistical power. RESULTS: False-positive frequencies of 2-74% were observed for asymptomatic neurocognitive impairment/mild neurocognitive disorder and 0-8% for HIV-associated dementia. False-positive frequencies depended on the definition of an abnormal cognitive domain, Z score thresholds and neuropsychological battery size. Misclassification led to clinically important overestimation of prevalence and dramatic decreases in power. CONCLUSIONS: Minimizing false-positive frequencies is critical to decrease bias in prevalence estimates and minimize reductions in power in studies of association, particularly for mild forms of HAND. We recommend changing the Z score threshold to ≤-1.5 for mild impairment, limiting analysis to 3-5 cognitive domains and using the average Z score to define an abnormal domain.

Screening for HIV-associated peripheral neuropathy in resource-limited settings.

INTRODUCTION: Peripheral neuropathy is the most common neurological complication of human immunodeficiency virus (HIV) infection but is widely under-diagnosed in resource-limited settings. We investigated the utility of screening tools administered by nonphysician healthcare workers (HCW) and quantitative sensory testing (QST) administered by trained individuals for identification of moderate/severe neuropathy. METHODS: We enrolled 240 HIV-infected outpatients using 2-stage cluster randomized sampling. HCWs administered the several screening tools. Trained study staff performed QST. Tools were validated against a clinical diagnosis of neuropathy. RESULTS: Participants were 65% women, mean age 36.4 years, median CD4 324 cells/µL. A total of 65% were taking antiretrovirals, and 18% had moderate/severe neuropathy. The screening tests were 76% sensitive in diagnosing moderate/severe neuropathy with negative predictive values of 84-92%. QST was less sensitive but more specific. CONCLUSIONS: Screening tests administered by HCW have excellent negative predictive values and are promising tools for scale-up in resource-limited settings. QST shows promise for research use.

Effectiveness, relevance, and feasibility of an online neurocritical care course for African healthcare workers.

The majority of neurological disorders exist in low- and middle-income countries, but these nations have the fewest neurologists and neurological training opportunities worldwide. The objective of this study was to assess the effectiveness, relevance, and feasibility of a five-day neurocritical care course delivered online to African healthcare workers and to understand participants' prior neurological and neurocritical care training experiences. We offered the Neurocritical Care Society's Emergency Neurological Life Support (ENLS) course covering 14 neurocritical conditions via Zoom to 403 African healthcare workers over a 4-day period. An additional day was devoted to management of neurological emergencies in resource-limited settings. Participants completed pre- and post-course surveys to assess the effectiveness, relevance, and feasibility of the overall course to their settings. 318 participants (46% female; 56% residents; 24% neurologists; 9.0 ± 6.7 years practicing medicine) from 11 African countries completed the pre-course self-assessment, and 232 completed the post-course self-assessment. 97% reported prior experience caring for patients with neurological emergencies but only 35% reported prior neurology training and 9% prior neurocritical care training. Pre-course and post-course comfort levels showed statistically significant improvements (p < 0.001) across all fourteen neurocritical topics. 95% of participants found the course relevant to their current practice setting, 94% agreed the Zoom online platform was easy to use, and 93% reported it facilitated their learning. Suggestions for course improvement included addition of non-critical neurological conditions and inclusion of locally available diagnostics and treatment modalities. Study results suggest virtual platforms may offer a way to improve neurology training in areas with reduced neurological workforce.