Auditory event-related potentials in patients with systemic lupus erythematosus

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.

A study of auditory evoked potentials in systemic lupus erythematosus patients

Systemic lupus erythematosus (SLE) is a multifactorial chronic systemic inflammatory disease, of unknown origin, characterized by the presence of autoantibodies and polymorphic clinical manifestations. This disease may involve multiple organs and systems. The most common findings are articular, cutaneous, vascular, renal, neurological, cardiac, gastrointestinal, hematological, ocular, and auditory abnormalities.

Aim

To investigate the central auditory function of subjects diagnosed with Systemic Lupus Erythematosus (SLE).

Material and Method

A time-series study was made of sixty subjects, aged between 21 and 46 years, which were divided into a control (n=30) and an experimental group (n=30). A clinical history, audiological evaluation (pure tone audiometry, speech audiometry and immitance testing) and short (ABR), middle (MLR) and long latency (LLAEP) potentials were carried out in all subjects. Results: No statistically significant differences were observed between the groups in any of the evaluations.

Conclusions

In this study there were no differences in short, middle and long latency auditory potentials between the control and experiment subject groups..

Seizure frequency affects event-related potentials (P300) in epilepsy

To analyse the effect of epilepsy an P300 event-related potentials we studied 27 patients with idiopathic generalized epilepsy (IGE), 13 patients with temporal lobe epilepsy (TLE) and 60 normal controls. The prolongation of P300 latencies was highly cor related with increasing age in controls but not epileptic patients. The age-corrected P300 latency used in this study was actual P300 latency-predicted P300 latency (predicted P300 (msec)=306.20+0.79 age, P=0.001, R2=0.32). By using ANOVA analysis, the age-corrected latencies of P300 were significantly longer in TLE patients (19.72+/-47.82 msec, mean+/-SD) than in IGE patients (10.97+/-36.97 msec) and controls (0.23+/-20.28 msec). Likewise, significantly prolonged P300 latencies were seen in the epileptic patients with a seizure frequency more than 400 times (37.21+/-47.50 msec). The multivariate-adjusted odds ratio for those who had TLE was 10.97 (95% CI=3.99 - 30.14 ) in the prolonged latencies of P300 compared with that of IGE patients. The odds ratio of longer latencies of P300 was 7.43 (95% CI=2.75 - 20.08) among those who had a high seizure frequency (> or =400 times) compared with those who had a low seizure frequency. No interaction between TLE and high frequency of attacks was found. The age at onset of seizure and duration of illness was not associated with P300 latency prolongation. From the above results, we might infer that the seizure type of TLE and a high frequency of seizure are two major independent precipitate factors for abnormal latencies of P300 in the epileptic patients.

[Evidence of cerebral involvement in the chronic stage of Chagas disease obtained using the P300 potential and quantified electroencephalography]

It is already known the involvement of the peripheral nervous system in chronic stages of Chagas disease. Tomographic and neuropsychological evidence of brain compromise has been included recently. In order to evaluate the neurophysiological counterpart of cerebral involvement, we studied P300 evoked potential and quantified EEG (qEEG) of 35 patients (26-55 years), and compared to an equal number of control subjects (29-55 years). We have found increased P300 latency compared to the control group (331.24 +/- 24. 02 vs 318.86 +/- 23.18) (p=0.01716). qEEG showed lower relative Beta 1 power in the patients group (p=1.6E5), and the principal frequency 1 Hz slower in the same group (p=0.01077). Multivariate analysis showed three subpopulations: a normal one, pathological one with higher Alpha power and pathological with Alpha decrement and DeltaTheta increment. Pathological findings represented 20% for the qEEG and 11.43% for cognitive potentials. Cardiac and neurologic involvement were not correlated. We conclude that there is clear electrophysiological evidence of cerebral involvement in chronic Chagas disease, thus reinforcing findings obtained by other methods.

Effects of aging on P3 components of somatosensory event-related potentials elicited by different stimulus conditions. Conventional averages and single-trial analysis

Effects of aging on P3 components of somatosensory event-related potentials (ERPs) under different stimulus conditions were studied in healthy subjects using conventional averages and single-trial waveform analysis. The P3 component elicited by target stimuli (target P3) and that elicited by rare nontarget stimuli (nontarget P3) showed significant latency prolongation with age at the rate of 1.6 and 2.0 ms/year, respectively. The nontarget P3 showed a greater trial-to-trial fluctuation of single-trial latency than the target P3, probably because 'passive attention' was more liable to fluctuate. The variabilities of single-trial target P3 latency and of single-trial nontarget P3 latency were not correlated with age. Thus, the P3 latency prolongation with age might not be attributable to fluctuation in latency resulting from impairment of attention with aging.