What EEG findings are characteristic of AIDS dementia?

Updated: Oct 09, 2019
  • Author: Eli S Neiman, DO, FACN; Chief Editor: Selim R Benbadis, MD  more...
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EEG abnormalities usually precede brain atrophy on computed tomography (CT) of the brain. Generalized or multifocal slowing may be observed. Computerized EEG is abnormal in most cases. About one half of patients who have normal neurologic findings on physical examination exhibit abnormal EEGs.

Thomas et al described a 40-year-old HIV-positive, right-handed homosexual man who was admitted for progressive mental deterioration coexisting with permanent, segmental, middle-amplitude, arrhythmic, asynchronous, and asymmetrical myoclonic jerks. EEG demonstrated frontocentral bursts of rhythmic triphasic 1.5- to 2-Hz sharp waves similar to the characteristic periodic pattern of CJD. Biological investigations were negative, thus ruling out a metabolic encephalopathy. [48]

Dramatic neurological improvement occurred shortly after initiation of intravenous and then oral zidovudine, which produced absolute EEG normalization. This unusual electroclinical presentation of the AIDS dementia complex underlines the fact that this condition presents a diagnostic challenge, particularly in individuals in whom HIV infection has not been diagnosed previously.

Canafoglia et al described a case of a HIV-seropositive patient with ataxia and upper limb rhythmic myoclonus. [49] Electromyographic (EMG) recordings of the forearm muscles correlated with frontocentral rhythmic activity on EEG. This movement disorder should be considered a rhythmic variant of cortical myoclonus. HIV infection may have caused a dysfunction in the central nervous system pathways similar to that occurring in genetically determined conditions characterized by cortical myoclonus.

Sinha et al described various electrophysiologic abnormalities in HIV encephalopathy. [50]

Polich et al found greater frontal delta power in HIV cases than in control subjects. [51]

Ferrari et al described 2 patients with HIV type 1 infection who presented new-onset epilepsia partialis continua (EPC) as an early manifestation of progressive multifocal leukoencephalopathy (PML). [52] PML represents an increasingly recognized cause of new-onset seizures in both seropositive and seronegative patients.

Diehl et al followed 117 HIV patients with EEG. Serial EEGs on 117 HIV patients without any clinical signs of secondary neuromanifestations were studied in order to document EEG changes in the course of HIV infection. Clinical signs of HIV-associated encephalopathy presented in 18 patients at the first examination and 23 at reexamination. Significant slowing of background activity occurred in the course of the disease. The results of this study indicated progressive central nervous system (CNS) dysfunction with worsening of the immunostatus. [53]

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