Less is more: neural mechanisms underlying anomia treatment in chronic aphasic patients.

See Thompson and Woollams (doi:10.1093/brain/awx264) for a scientific commentary on this article. Previous research with aphasic patients has shown that picture naming can be facilitated by concurrent phonemic cueing [e.g. initial phoneme(s) of the word that the patient is trying to retrieve], both as an immediate word retrieval technique, and when practiced repeatedly over time as a long-term anomia treatment. Here, to investigate the neural mechanisms supporting word retrieval, we adopted­for the first time­a functional magnetic resonance imaging task using the same naming procedure as it occurs during the anomia treatment process. Before and directly after a 6-week anomia treatment programme, 18 chronic aphasic stroke patients completed our functional magnetic resonance imaging protocol­a picture naming task aided by three different types of phonemic cues (whole words, initial phonemes, final phonemes) and a noise-control condition. Patients completed a naming task based on the training materials, and a more general comprehensive battery of language tests both before and after the anomia treatment, to determine the effectiveness and specificity of the therapy. Our results demonstrate that the anomia treatment was effective and specific to speech production, significantly improving both patients' naming accuracy and reaction time immediately post-treatment (unstandardized effect size: 29% and 17%, respectively; Cohen's d: 3.45 and 1.83). Longer term gains in naming were maintained 3 months later. Functional imaging results showed that both immediate and long-term facilitation of naming involved a largely overlapping bilateral frontal network including the right anterior insula, inferior frontal and dorsal anterior cingulate cortices, and the left premotor cortex. These areas were associated with a neural priming effect (i.e. reduced blood oxygen level-dependent signal) during both immediate (phonemically-cued versus control-cue conditions), and long-term facilitation of naming (i.e. treated versus untreated items). Of note is that different brain regions were sensitive to different phonemic cue types. Processing of whole word cues was associated with increased activity in the right angular gyrus; whereas partial word cues (initial and final phonemes) recruited the left supplementary motor area, and right anterior insula, inferior frontal cortex, and basal ganglia. The recruitment of multiple and bilateral areas may help explain why phonemic cueing is such a successful behavioural facilitation tool for anomia treatment. Our results have important implications for optimizing current anomia treatment approaches, developing new treatments, and improving speech outcome for aphasic patients.

Benefit of phonemic cueing on confrontation naming in Alzheimer's disease.

Objective: Deficits in confrontation naming vary among persons with Alzheimer's disease (AD), including the extent to which phonemic cueing is helpful in generating the target word. This study examined neuropsychological correlates of phonemic cueing benefit and the influential effects of AD severity, estimated premorbid intellectual functioning, and apolipoprotein E genotype status.Method: Participants were 1104 individuals with mild to moderate AD who were administered the Boston Naming Test (BNT) as part of their initial neuropsychological evaluation.Results: Mild AD subjects benefited from phonemic cues significantly more than moderate AD subjects. Individuals with higher estimated premorbid IQ benefited more from phonemic cueing. Differences in phonemic cueing benefit between carriers and noncarriers of the ApoE ε4 allele were accounted for by naming ability, with carriers performing better on naming tasks compared to noncarriers. Phonemic cueing benefit uniquely contributed to cognitive performance on some semantic measures, phonemic fluency, and one nonsemantic visuospatial task.Conclusion: Individuals with probable AD who benefit more from phonemic cueing during confrontation naming tend to have higher estimated premorbid IQ and are milder in dementia severity. There is a positive association between phonemic cueing benefit and performance on select semantic measures and verbal fluency. Differences in phonemic cueing benefit between carriers and noncarriers of APOE ε4 allele can be explained by spontaneous naming performance. Results suggest complexity of underlying mechanisms involving confrontation naming, phonemic cueing, and lexical access and the factors that influence them.