P300 latency and neurocognitive functioning in recently diagnosed human immunodeficiency virus patients

Aim: To assess the P300 latency and amplitude in recently diagnosed human immunodeficiency virus (HIV)-positive patients and compare the same with a healthy control group. Further an attempt was made to study the correlation between P300 amplitude and latency (in milliseconds) with neurocognitive functions.

Materials and methods: Thirty newly diagnosed HIV-positive patients who on self report did not have any cognitive dysfunction were recruited. The patients were evaluated for P300 evoked response using the odd-ball paradigm, MMSE and a comprehensive neuropsychological battery. The P300 latencies were compared with 30 normal control subjects.

Results: The mean P300 latency (in milliseconds) of the HIV-positive subjects was significantly more than the healthy control group. The mean amplitude of HIV group was significantly less than the normal control group. On MMSE, 7 HIV-positive subjects had mild cognitive impairment (MMSE total score 20-23), six patients had minimal cognitive impairment (MMSE total score 24-27) and 17 patients had no cognitive impairment (MMSE total score >27). On neuropsychological test battery only three (10%) of HIV-positive subjects had cognitive dysfunction. There was negative correlation between P300 latency (in milliseconds) and MMSE total score and performance on Koh's Block subtest.

Conclusion: P300 may be a reliable indicator of cognitive impairments in HIV patients.