ERP P300 and brain magnetic resonance imaging in patients with vibroacoustic disease.

INTRODUCTION

Subjects occupationally exposed to large pressure amplitude (> or = 90 dB SPL) and low frequency (< or = 500 Hz) (LPALF) noise for long term periods (>10 yr) can develop vibroacoustic disease (VAD). One of the earliest complaints of VAD patients deals with memory and attention disturbances. On the other hand, in over 50% of these patients, magnetic resonance imaging (MRI) of the CNS revealed cortical atrophy and dilation of the perivascular spaces, and small hyperintense lesions in T2 of the cerebral white matter, basal ganglia, and brainstem. The purpose of this study is to investigate whether there is any relationship between these morphological changes and the event-related potentials (ERP) P300 parameters.

METHODS

Sixty aeronautical workers with more than 10 yr of LPALF noise exposure were studied using brain MRI and ERP P300. A careful neurological examination had been previously performed on all of them.

RESULTS

The neurological examination revealed abnormalities in 80%, the most common finding being the archaic palmo-mental reflex. Some 37 subjects had hyperintense foci in T2 of the subcortical and periventricular white matter, the basal ganglia and the brainstem. Comparing the ERP P300 amplitude and latency values, morphology and topography, obtained in these 37 subjects with the data from the 23 who did not have any morphological changes in CNS, we found a strong correlation between the brain MRI lesions and the neurophysiological changes (p < 0.01).

CONCLUSIONS

These results are important for understanding the pathophysiology of the cognitive impairment found in VAD patients.