[Changes in the EEG background rhythm and in the hyperventilation effect at different stages of HIV infection]

The visual evaluation of 370 clinical EEGs of 125 patients in different stages of the HIV-infection as well as 42 HIV-seronegative volunteers of the same high risk population (male homosexuals) proved the increasing appearance of CNS dysfunction with progression of the disease. An especially established hyperventilation-index for a semiquantitative evaluation of hyperventilation response showed an increase of slow-wave activity in the course of the infection. The appearance of slow-waves as well as a significant slowing of background activity in advanced stages of the HIV-infection can be regarded as unspecific signs of a beginning diffuse functional CNS disorder caused by a direct affection of the CNS through the Human Immunodeficiency Virus (HIV). The EEG changes in early stages are not specific as to their causative agent and do not allow the distinction between primary and secondary CNS involvement. The changes may precede clinical-neurological alterations.