Study Design/MethodsConsecutive HIV positive adults, with history of low nadir, previous/current EFV use, and reported concentration problems and memory loss, enrolled since 05/018. Unbalanced psychiatric syndrome, current drug use, previous cerebrovascular damages, and foreigners with poor italian understanding were excluded. Who met the aforementioned criteria were screened for HAND with MINI Addenbrooke’s cognitive examination (MACE) 2-3, 5and International HIV dementia scale (IHDS) 4. All patients with a score< 10 and< 26 respectively, underwent complete neuropsychological examination of: memory, attention function, language, praxia/visual-spatial function and processing speed. Patients with a diagnosis of HAD performed brain MRI and lumbar puncture to detect HIV and JC Virus. Patients with detectable HIV viral load and/or positive JCV PCR in the CNS and/or suggestive MRI of encephalopathy with white matter damage, changed cART for optimizing CNS penetration.