Lorazepam impairs both visual and auditory perceptual priming.

RATIONALE: Lorazepam has been repeatedly shown to impair both explicit memory and perceptual priming, a form of implicit memory, in the visual domain. However, the effects of this benzodiazepine on priming in other perceptual domains, such as auditory priming, have never been explored.

OBJECTIVE

The present study investigated whether the deleterious effects of lorazepam on perceptual priming are restricted to the visual domain, or if they could be extended to the auditory domain.

METHODS

Thirty-two healthy volunteers were randomly assigned to two parallel groups, placebo and lorazepam 0.038 mg/kg. The drug was administered orally, following a double-blind procedure. In the same subjects, perceptual priming was assessed in the auditory and visual domains using similar word-stem completion tasks, and explicit memory was explored using a free-recall task.

RESULTS

Lorazepam markedly reduced free-recall performance for visually and auditorily presented words. Lorazepam equally impaired visual and auditory priming. In the auditory word-stem completion task, prior presentation of a word facilitated perception of its stem in the placebo group. This facilitation effect was not observed in the lorazepam group. The lorazepam-induced impairment of priming was not due to sedation or explicit contamination.

CONCLUSION

These results indicate that the deleterious effects of lorazepam on priming are not restricted to the visual modality, but extend to the auditory modality.