Effect of Healthy Aging and Gender on Syntactic Input Processing: A P600 Event-Related Potential Study.

PURPOSE: This study aimed to investigate the effect of healthy aging and gender, as well as the interaction, thereof, on syntactic input processing during sentence comprehension. This was achieved through the recording of the P600 event-related potential. METHOD: Sixty Flemish (native speakers of Dutch) participants (30 men and 30 women), equally distributed into three age groups (young, middle-aged, and older adults), were subjected to a visually presented word order violation task under simultaneous electro-encephalography recording. The task contained 60 sentences, of which half were grammatical and half contained a word order violation. P600 responses were analyzed for amplitude, latency, topographical distribution, and source localization. RESULTS: Regarding the effect of healthy aging, no age-related differences were found for the amplitude, onset latency, and topographical distribution of the P600 effect (difference wave). Although aging effects on the P600 effect amplitude were absent, a reduced P600 amplitude in response to both the grammatical and ungrammatical sentences was found, next to a reduced overall degree of source activation in linguistic regions of interest. Also, a reduced behavioral accuracy in response to the word order violation was observed in the older adults group. Regarding the effect of gender, females exhibited a larger P600 effect amplitude and a reduced behavioral accuracy compared to males. No gender-related differences were found for P600 effect onset latency, topographical distribution, and source activation. CONCLUSIONS: While this study demonstrates no effect of aging on the P600 effect, the lower behavioral response and absence of any activation shift argues against functional compensation. Moreover, although increased neural activation in women combined with their reduced behavioral accuracy may indicate the use of different cognitive strategies in men and women, source localization analysis could not objectify this hypothesis.

Aging and sex effects on phoneme perception: An exploratory mismatch negativity and P300 investigation.

BACKGROUND & AIMS: The mismatch negativity (MMN) and P300 event-related potentials (ERPs) have been studied in relation to phoneme discrimination and categorization, respectively. Although the effects of aging and sex on pure-tone perception have been widely investigated using these ERPs, evidence relating to phoneme perception is scarce. The current study aimed to provide insight into the effects of aging and sex on phoneme discrimination and categorization, as measured through the MMN and P300. METHOD: An inattentive and attentive oddball paradigm containing a phonemic articulation place contrast were administered during EEG registration in sixty healthy individuals (thirty males and females), of which an equal number of young (20-39 years), middle-aged (40-59 years) and elderly (60+ years) subjects were included. The amplitude, onset latency and topographical distribution of the MMN and P300 effect, as well as the amplitude of the P1-N1-P2 complex, were analyzed for age group and sex differences. RESULTS: With respect to aging, elderly subjects demonstrated a reduced MMN and P300 amplitude compared to the young group, whereas the scalp distribution of both components was unaffected. No aging effects on the P1-N1-P2 complex were found. In elderly individuals, the P300 was found to be delayed compared to the young group, while no such effect on MMN latency could be observed. No differences in MMN and P300 measures could be identified between males and females. CONCLUSION: Differential effects of aging were found on the MMN and P300, specifically in terms of latency, in relation to phoneme perception. In contrast, sex was found to scarcely affect both processes.

Constrained-Induced Dysarthria Therapy: Case Report.

We describe a 33-year-old woman with chronic bulbar dysarthria after ischemic brainstem stroke who underwent a new form of constraint-induced therapy, namely constraint-induced dysarthria therapy, based on three principles: avoidance of supportive devices, intensive therapy, and gradually augmenting difficulty. After a 2-month intervention, improvement was noted for speech intelligibility, fluency, and intensity. This led to increased communicative participation, including during conversation situations, which has been maintained over a 12-month follow-up.