This a cross-sectional study to determine the prevalence of HIV-related Neurological Disorders in the countries of the Asia-Pacific Region. Researchers will visit each country site for a period of 2-3 weeks and work with local investigators. Outpatients will be evaluated once-only for the presence of HIV-related symptomatic peripheral neuropathy and HIV-related Neurocognitive Impairment. Inpatients at the sites will be evaluated once-only for the presence of HIV dementia, cerebral toxoplasmosis, cerebral tuberculosis, cryptococcal meningitis, lymphoma, PML and CMV encephalitis.