Using McGurk effect to detect speech-perceptional abnormalities in refractory epilepsy

Abstract

Background: McGurk effect is a perceptual phenomenon that demonstrates an interaction between hearing and vision in speech perception. A wide range of neuropsychological deficits have been described in people with long-standing epilepsy, which affect multimodal integration in speech perception and hence refractory epilepsy patients are ideal for testing the McGurk effect.

Materials and methods: We studied the McGurk effect in 50 patients diagnosed with medically refractory left or right hemispheric epilepsy based on clinical, radiological, and electrophysiological data.

Results: The McGurk effect was better perceived (p = 0.006) in patients with left hemispheric epilepsy (n = 12, 71%) compared to right (n = 5, 29%). The other factors which compromised the perception of the McGurk effect were impairments in visual memory (p = 0.041), facial emotion recognition (p = 0.001), and lip-reading (p = 0.006). Perception of the McGurk effect reduced significantly (p = 0.006) when the epilepsy duration was 10 years or beyond.

Conclusion: The McGurk effect can be used in refractory epilepsy patients, to detect subtle abnormalities in speech perception, before significant irreversible speech and language dysfunction become evident.

Keywords: Audiovisual integration; Epilepsy; McGurk effect; Speech perception.