Potenciais evocados auditivos de longa latência em adultos com HIV/Aids

Visual evoked and event-related brain potentials in HIV-infected adults: a longitudinal study over 2.5 years

PURPOSE

The aim of this neurophysiological study was to monitor changes in the visual and cognitive function of HIV-infected patients treated with combination antiretroviral therapy.

METHODS

Eleven adult Czech HIV+ patients, with a mean age of 35 years and CD4 cell count ≥ 230 × 10⁶ cells/L of blood at the time of enrollment, underwent four to six examinations over the course of 2.5 years to evaluate pattern-reversal and motion-onset visual evoked potentials (P-VEPs and M-VEPs), visually driven oddball event-related potentials (ERPs) and Montreal Cognitive Assessments. In addition to evaluating the intraindividual change in the observed parameters, we also compared patient data to data from eleven age- and gender-matched controls.

RESULTS

We did not find any significant differences in P-VEPs between the patients and controls or in the paired comparison of the first and last visit. The only significant finding for P-VEPs was a linear trend in prolongation of the 20' P-VEP P100 peak time. In M-VEPs, we found a significant intergroup difference in the N160 peak time recorded during the first visit for peripheral M-VEPs only. During the last visit, all N160 peak times for patients differed significantly from those of the control group. The only intervisit difference close to the level of significance was for peripheral M-VEPs, which confirmed the trend analysis. No significant differences between patients and controls were found in the ERPs, but the P300 peak time showed a significant difference between the first and last visits, as confirmed by the trend. Patient reaction time was not significantly delayed at the first visit; however, it was prolonged with time, as confirmed by the trend.

CONCLUSION

Our aim was to evaluate whether antiretroviral treatment in HIV+ patients is sufficient to preserve brain visual function. The optic nerve and primary visual cortex function tested by the P-VEPs seem to be preserved. The prolongation of the M-VEPs suggests an individually detectable decline in CNS function, but these changes did not show a progression during the follow-up. From a longitudinal perspective, the trends in peak time prolongation of the 20' P-VEP, peripheral M-VEP, ERP and reaction time suggest a faster decline than that caused by aging in healthy populations, as previously described in a cross-sectional study.

Audiological and electrophysiological alterations in HIV-infected individuals subjected or not to antiretroviral therapy

Introduction

The Human Immunodeficiency Virus (HIV) and infections related to it can affect multiple sites in the hearing system. The use of High Activity Anti-Retroviral Therapy (HAART) can cause side effects such as ototoxicity. Thus, no consistent patterns of hearing impairment in adults with Human Immunodeficiency Virus / Acquired Immune Deficiency Syndrome have been established, and the problems that affect the hearing system of this population warrant further research.

Objectives

This study aimed to compare the audiological and electrophysiological data of Human Immunodeficiency Virus-positive patients with and without Acquired Immune Deficiency Syndrome, who were receiving High Activity Anti-Retroviral Therapy, to healthy individuals.

Methods

It was a cross-sectional study conducted with 71 subjects (30–48 years old), divided into groups: Research Group I: 16 Human Immunodeficiency Virus-positive individuals without Acquired Immunodeficiency Syndrome (not receiving antiretroviral treatment); Research Group II: 25 Human Immunodeficiency Virus-positive individuals with Acquired Immunodeficiency Syndrome (receiving antiretroviral treatment); Control Group: 30 healthy subjects. All individuals were tested by pure-tone air conduction thresholds at 0.25–8 kHz, extended high frequencies at 9–20 kHz, electrophysiological tests (Auditory Brainstem Response, Middle Latency Responses, Cognitive Potential).

Results

Research Group I and Research Group II had higher hearing thresholds in both conventional and high frequency audiometry when compared to the control group, prolonged latency of waves I, III, V and interpeak I–V in Auditory Brainstem Response and prolonged latency of P300 Cognitive Potential. Regarding Middle Latency Responses, there was a decrease in the amplitude of the Pa wave of Research Group II compared to the Research Group I.

Conclusions

Both groups with Human Immunodeficiency Virus had higher hearing thresholds when compared to healthy individuals (group exposed to antiretroviral treatment showed the worst hearing threshold) and seemed to have lower neuroelectric transmission speed along the auditory pathway in the brainstem, subcortical and cortical regions.

Applicability of the P300 frequency pattern test to assess auditory processing

Temporal ordering and auditory attention are important skills in information processing, being evaluated by a behavioral test, as the frequency pattern test (FPT) in temporal ordering (TO) and electrophysiological testing, as the P300 in auditory attention.

OBJECTIVE

To analyze the applicability of FPT and P300 as testing for auditory processing.

METHOD

We performed an integrative literature review, with papers that met the inclusion criteria, using the MedLine, LILACS and SciELO databases, with the keywords: hearing attention, P300 evoked potential, P300 and electrophysiology, temporal ordering, processing and FPT. We found 13 papers concerning the use of the TPF and 16 regarding the use of P300.

RESULTS

The TPF was the most used test in the evaluation of TO, presented in a diotic way in individuals with language disorders, musicians, blind people, rural workers and different age groups. The P300 is used in the frequency of 1000 Hz in the frequent stimulus and 2000 Hz for the rare stimulus, applicable in individuals of both genders, different age groups, and in patients with Down syndrome, liver cirrhosis, AIDS and Sleep Apnea Syndrome.

CONCLUSION

The FPT and P300 are efficient instruments used to assess the intended skills.

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.

Saúde auditiva, o vírus da imunodeficiência humana e a síndrome da imunodeficiência adquirida: uma revisão

TEMA: a Síndrome da Imunodeficiência Adquirida (SIDA/AIDS) é causada pelo Vírus da Imunodeficiência Humana (VIH/HIV), e resulta numa imunidade reduzida, o que torna o indivíduo mais susceptível a doenças e infecções oportunistas. Com o avanço da doença as estruturas do sistema auditivo central podem ser comprometidas pela ação direta do vírus ou decorrente de infecções secundárias e neoplasias. O portador do HIV/AIDS pode também se tornar mais vulnerável a outras patologias do ouvido. OBJETIVO: o objetivo desta revisão foi exploratório, visando identificar os possíveis pontos de interseção entre distúrbios auditivos e a Síndrome da Imunodeficiência Adquirida. Realizou-se uma revisão da literatura sobre a saúde auditiva dos portadores de HIV/AIDS e foi discutido o impacto potencial de patologias auditivas na qualidade de vida. CONCLUSÃO: a literatura sugere que várias possiveis associações existam entre os distúrbios auditivos e a Síndrome da Imunodeficiência Adquirida e o Vírus da Imunodeficiência Humana. Profissionais de saúde, inclusive aqueles dos serviços públicos no Brasil, deveriam examinar a necessidade de iniciativas de saúde auditiva dirigida aos portadores de HIV/AIDS para prevenir patologias auditivas ou reduzir seu impacto na qualidade de vida.