A study of auditory evoked potentials in systemic lupus erythematosus patients

Electrophysiological Study on Cognitive Function in Systemic Lupus Erythematosus Patients With Previous Neuropsychiatric Involvement

This study aimed to evaluate P300 as an electrophysiological marker of cognitive function in patients with systemic lupus erythematosus (SLE) who had previous neuropsychiatric (NPSLE) involvement and were diagnosed to have cognitive impairment by standard neuropsychological tests. Event-related potentials (ERPs) were assessed by the auditory and visual oddball paradigms. Amplitude and latency of P300 at the frontal (Fz), central (Cz), and parietal (Pz) regions were determined and compared with controls. P300 detection was performed in NPSLE patients with pre-diagnosed cognitive impairment (n = 9), matched SLE patients without previous NPSLE (non-NPSLE) (n = 9), and healthy controls (n = 15). Auditory oddball task did not show any P300 abnormality between groups. Visual oddball task revealed reduced amplitude of P300 over Fz ( P = .002) and Cz ( P = .009) electrodes in NPSLE patients compared with healthy controls and among those who had predominant memory deficit ( P = .01 at Fz). Abnormal P300 was also observed in non-NPSLE patients at Fz and Cz. Using visual oddball paradigm, abnormal P300 was found in NPSLE patients over frontal and parietal regions compared with normal controls but was not discriminative from possible subclinical disease in non-NPSLE patients. In conclusion, visual oddball paradigm was a more sensitive electrophysiological marker than auditory oddball paradigm for cognitive impairment in NPSLE patients.

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.

Auditory function in patients with systemic lupus erythematosus

OBJECTIVE

Patients with systemic lupus erythematosus (SLE) may develop hearing and balance disorders as a result of the immune-mediated inner ear damage due to vasculitis or ototoxicity of drugs used in SLE treatment. The aim of the study was evaluation of the hearing organ disorders in patients with SLE with particular regard to their prevalence and relationship to duration and severity of disease. The severity was assessed from involvement of organs that resulted in poorer SLE outcome, i.e. kidneys and central nervous system (CNS), and from the presence of antibodies associated with unfavourable SLE prognosis.

METHODS

Thirty-five unselected, consecutive patients (33 women, two men, mean age 47.8 years) with SLE diagnosed in compliance to the international diagnostic criteria of the American Rheumatism Association (1982) were enrolled into the study. The control group consisted of 30 otologically healthy persons matched to the SLE group for age and sex. Case history was recorded for all patients from questionnaire data and laryngological examinations were performed, followed by pure-tone, speech and impedance audiometry and auditory brainstem response audiometry (ABR).

RESULTS

In the anamnesis 71.4% of patients reported vertigo, 62.9% headaches, 40% tinnitus, 25.7% hyperacusis, 17.1% hearing loss and 2.9% ear fullness. It was found that SLE patients had a significantly poorer mean hearing thresholds than the control group for all frequencies, except for 500; 2000 and 4000 Hz. Longer ABR latency averages were observed in the group of SLE patients compared to control. Ten patients (28.6%) developed high-frequency and symmetric sensorineural hearing loss (SNHL). Significant positive correlation between mean air-conduction hearing thresholds and SLE duration (r = 0.46, p < 0.001) was found. After taking age into consideration, hearing acuity in SLE was related to duration of disease in younger patients. Furthermore, no relation was seen between hearing level and severity of disease.

CONCLUSIONS

Auditory system involvement ought to be considered as one of elements of the clinical picture of systemic lupus erythematosus while determination of its character, original or secondary, requires further research.