Priming Sentence Production in Older Adults: Evidence for Preserved Implicit Learning.

Purpose: Structural priming- speakers' unconscious tendency to echo previously encountered message-structure mappings - is thought to reflect the processes of implicit language learning that occur throughout the lifespan. Recently, structural priming has also been used as a means to facilitate language re-learning in age-related language disorders such as aphasia. However, little evidence is available on whether structural priming remains effective in healthy aging, limiting clinical translation of the structural priming paradigm. This study examined the impact of aging on the strength and longevity of abstract structural priming and lexical boost effects. Method: Twenty-four young and 24 older adults participated in a collaborative picture-matching task where the participant and experimenter took turns describing picture cards using transitive and dative sentences. In Experiment 1, a target was elicited immediately following a prime (0-lag), whereas two filler items were embedded between a prime and a target sentence in Experiment 2 (2-lag) to examine longer-term priming effects. In both experiments, the verb was repeated for half of the prime-target pairs to examine lexical boost on structural priming. Results: At immediate priming, older adults showed both abstract structural priming and lexical boost in transitives and datives, similar to young adults. At longer-term priming, only abstract priming effects were significant in both groups of participants, with no evidence of age-related reduction in priming. Conclusions: Both lexically-specific and independent mechanisms of structural priming remain resilient in older adults, supporting the view that structural priming reflects life-long language learning. Further, the findings provide empirical basis for applying structural priming to elderly clinical populations.

Associations between blood metal/ metalloid concentration and human semen quality and sperm function: A cross-sectional study in Hong Kong.

BACKGROUND: The association between metal/metalloid exposure on human sperm quality is still inconclusive. There is a lack of data on the effect of metal/metalloid on sperm function. METHODS: The aim of this study was to clarify the association between blood metal/metalloid concentration and traditional and functional sperm parameters, the blood concentration of Pb, Hg, Cd, As, Ni, Mo, Zn, Cu, Se, Fe, Mg, Cr and Ca of 288 men in Hong Kong were assessed by inductively coupled plasma-mass spectrometry, and sperm parameters including sperm concentration, motility, morphology, vitality, total sperm count, total motile sperm count, sperm DNA fragmentation and sperm acrosome reaction were measured. Demographic and lifestyle questionnaires were also provided for all participants. Multivariable linear regression analysis was performed to test the association between blood metal/ metalloid concentration and semen parameters after adjusting for relevant confounding variables. RESULTS: The results showed that moderate to high level of blood Pb concentration (>27.19 µg/L) appeared to be negatively associated with sperm morphology (P < 0.05); high level of blood Cd concentration (>1.44 µg/L) was negatively associated with sperm acrosome reaction (P < 0.05); Mo was positively associated with semen volume (P < 0.05), however, high level of blood Mo concentration (>13.52 µg/L) was negatively associated with sperm vitality (P < 0.05); high level of blood Zn concentration (>6.20 mg/L) was positively associated with sperm vitality (P < 0.05); moderate level of blood Fe concentration (526.89-566.63 mg/L) was positively associated with sperm acrosome reaction (P < 0.05); moderate level of blood Ca concentration (55.92-66.10 mg/L) was positively associated with semen volume (P < 0.05); however, lower level of blood Ca concentration (45.90-55.92 mg/L) was negatively associated with sperm morphology (P < 0.05). CONCLUSIONS: Our results suggested that the sperm function could be affected by blood Cd and Fe concentration and traditional sperm parameters could be affected by blood concentration of Mo, Zn, Pb and Ca.

Aligning sentence structures in dialogue: evidence from aphasia.

Syntactic alignment in dialogue is pervasive and enduring in unimpaired speakers, facilitating language processing and learning. Recent work suggests that syntactic alignment extends to the level of event-semantic properties (syntactic entrainment). Two experiments examined whether syntactic entrainment can ameliorate impaired message-structure mapping in persons with aphasia (PWA). In Experiment 1, participants first heard twelve picture descriptions, each using one of two suitable syntactic structures, prior to describing the same twelve pictures themselves. In Experiment 2, participants also repeated the heard picture descriptions, thereby increasing the depth of encoding for prime sentences. PWA showed a robust tendency to re-use previously encountered syntactic structures in their own production only in Experiment 2. They produced fewer 'mapping' errors (e.g., thematic role reversals) in Experiment 2 than in Experiment 1. Syntactic entrainment remains resilient in aphasia, strengthening their event-semantic-to-syntax mappings, at least when active encoding of prior message-syntax associations is ensured.

Effects of Verb Overlap on Structural Priming in Dialogue: Implications for Syntactic Learning in Aphasia.

Purpose Although there is increasing interest in using structural priming as a means to ameliorate grammatical encoding deficits in persons with aphasia (PWAs), little is known about the precise mechanisms of structural priming that are associated with robust and enduring effects in PWAs. Two dialogue-like comprehension-to-production priming experiments investigated whether lexically independent (abstract structural) priming and/or lexically (verb) specific priming yields immediate and longer, lasting facilitation of syntactic production in PWAs. Method Seventeen PWAs and 20 healthy older adults participated in a collaborative picture-matching task where participant and experimenter took turns describing picture cards using transitive and dative sentences. In Experiment 1, a target was elicited immediately following a prime. In Experiment 2, 2 unrelated utterances intervened between a prime and target, thereby allowing us to examine lasting priming effects. In both experiments, the verb was repeated for half of the prime-target pairs to examine the lexical (verb) boost on priming. Results Healthy older adults demonstrated abstract priming in both transitives and datives not only in the immediate (Experiment 1) but also in the lasting (Experiment 2) priming condition. They also showed significantly enhanced priming by verb overlap (lexical boost) in transitives during immediate priming. PWAs demonstrated abstract priming in transitives in both immediate and lasting priming conditions. However, the magnitude of priming was not enhanced by verb overlap. Conclusions Abstract structural priming, but not lexically specific priming, is associated with reliable and lasting facilitation of message-structure mapping in aphasia. The findings also suggest that implicit syntactic learning via a dialogue-like comprehension-to-production task remains preserved in aphasia.

Sentence production in Parkinson's disease.

While growing evidence reports changes in language use in non-demented individuals with Parkinson's disease (PD), the presence and nature of the deficits remain largely unclear. Researchers have proposed that dysfunctioning fronto-basal ganglia circuit results in impaired grammatical processes, predicting qualitatively similar language impairments between individuals with PD and agrammatic Broca's aphasia, whereas others suggest that PD is not associated with language-specific grammatical impairment. In addition, there is a paucity of research examining syntactic production in PD at the sentence-level. This study examined sentence production of individuals with PD, healthy older adults, and individuals with agrammatic Broca's aphasia. In Experiment 1, using a Cinderella story-telling task, proportion of grammatical sentences, number of embedded clauses and production of verb arguments in sentences were examined. In Experiment 2, a structured sentence elicitation task was used in which syntactic complexity of sentences (canonical vs. non-canonical word order) was systematically manipulated while minimizing demands for non-syntactic processing. Only the participants with agrammatic Broca's aphasia showed significantly impaired syntactic production in both experiments. Participants with PD did not show impaired syntactic production in either task, despite impairments in lexical retrieval, repetition of words and sentences, and speech production. These findings suggest that impaired syntactic processing may not be a core deficit underlying the changes in language use in non-demented PD. Changes in language use in PD are qualitatively different from language deficits in aphasia.