Dynamics of phonological–phonetic encoding in word production: Evidence from diverging ERPs between stroke patients and controls

Abstract

While the dynamics of lexical-semantic and lexical-phonological encoding in word production have been investigated in several event-related potential (ERP) studies, the estimated time course of phonological–phonetic encoding is the result of rather indirect evidence. We investigated the dynamics of phonological–phonetic encoding combining ERP analyses covering the entire encoding process in picture naming and word reading tasks by comparing ERP modulations in eight brain-damaged speakers presenting impaired phonological–phonetic encoding relative to 16 healthy controls. ERPs diverged between groups in terms of local waveform amplitude and global topography at ∼400ms after stimulus onset in the picture naming task and at ∼320–350ms in word reading and sustained until 100ms before articulation onset. These divergences appeared in later time windows than those found in patients with underlying lexical-semantic and lexical-phonological impairment in previous studies, providing evidence that phonological–phonetic encoding is engaged around 400ms in picture naming and around 330ms in word reading.