Nervous system involvement in asymptomatic HIV seropositive individuals: a cognitive and electrophysiological study

A significant proportion of human immunodeficiency virus (HIV) seropositive subjects may have subclinical asymptomatic involvement of the central and peripheral nervous system.

To detect subclinical neurological involvement in asymptomatic HIV seropositive individuals by clinical, mini mental state examination (MMSE) and various electrophysiological tests.

MMSE, EEG, nerve conduction (NC), and multimodality-evoked potential studies were evaluated in 20 asymptomatic HIV seropositive subjects.

The majority of the subjects were young (mean age: 29.5 +/- 8.9 yrs) and female (85%). The mean MMSE score was 25.8 +/- 2.3, which was marginally less than that of matched controls (26.3 +/- 2.4). Four subjects had a score of less than 23 suggesting subclinical cognitive impairment. EEG (n=19) was mildly abnormal in 8 cases: low alpha index (n=4), excess of fast background activity (n=3) and intermittent bursts of slow waves along with sometimes sharp waves (n=4). Motor NC studies (n=20) revealed a decreased mean nerve conduction velocity (NCV) compared to controls in the right median (P<0.05) and CP (P<0.001) nerves. Sensory NC studies revealed a decreased mean NCV in both the median (P<0.001) and sural (P<0.001) nerves compared with controls. Brainstem auditory evoked potential (BAEP) studies showed the involvement of the peripheral auditory pathway (23.5%). The somatosensory evoked potential (SSEP) study detected a delay of N20 latency in two. Only 3 subjects came for follow-up after 6 months.

Asymptomatic HIV seropositive subjects may have subclinical central and peripheral nervous system involvement. Long-term follow-up studies are essential for better understanding of the significance of these changes.