Verbal working memory and co-speech gesture processing.

Multimodal discourse requires an assembly of cognitive processes that are uniquely recruited for language comprehension in social contexts. In this study, we investigated the role of verbal working memory for the online integration of speech and iconic gestures. Participants memorized and rehearsed a series of auditorily presented digits in low (one digit) or high (four digits) memory load conditions. To observe how verbal working memory load impacts online discourse comprehension, ERPs were recorded while participants watched discourse videos containing either congruent or incongruent speech-gesture combinations during the maintenance portion of the memory task. While expected speech-gesture congruity effects were found in the low memory load condition, high memory load trials elicited enhanced frontal positivities that indicated a unique interaction between online speech-gesture integration and the availability of verbal working memory resources. This work contributes to an understanding of discourse comprehension by demonstrating that language processing in a multimodal context is subject to the relationship between cognitive resource availability and the degree of controlled processing required for task performance. We suggest that verbal working memory is less important for speech-gesture integration than it is for mediating speech processing under high task demands.

Event related spectral perturbations of gesture congruity: Visuospatial resources are recruited for multimodal discourse comprehension.

Here we examine the role of visuospatial working memory (WM) during the comprehension of multimodal discourse with co-speech iconic gestures. EEG was recorded as healthy adults encoded either a sequence of one (low load) or four (high load) dot locations on a grid and rehearsed them until a free recall response was collected later in the trial. During the rehearsal period of the WM task, participants observed videos of a speaker describing objects in which half of the trials included semantically related co-speech gestures (congruent), and the other half included semantically unrelated gestures (incongruent). Discourse processing was indexed by oscillatory EEG activity in the alpha and beta bands during the videos. Across all participants, effects of speech and gesture incongruity were more evident in low load trials than in high load trials. Effects were also modulated by individual differences in visuospatial WM capacity. These data suggest visuospatial WM resources are recruited in the comprehension of multimodal discourse.

Investigating the costs of major and minor cycling crashes in Tasmania, Australia.

OBJECTIVE: A pilot study to estimate the societal costs of cycling crashes in Tasmania. METHODS: A telephone-based questionnaire collected information on demographics, cycling habits and details of major and minor crashes. Costs were estimated from medical resource consumption, lost work and leisure time. RESULTS: The survey was completed by 136 cyclists. Participants reported 59 major crashes in five years preceding the interview and 27 minor crashes in 12 months. Mean (standard deviation) costs/major crash were $12,499 ($14,301), including direct medical costs $2,569 ($4,523), direct non-medical costs $372 ($728), indirect costs of $6,027 ($10,092) and costs of lost leisure time $3,531 ($7,062). Costs/minor crashes were $632 ($795), including direct non-medical costs of $225 ($601), productivity losses of $117 ($210) and costs of lost leisure time $290 (622). Total annual costs of major cycling crashes in Tasmania were $4,239,097 ($4,850,255). CONCLUSIONS: Indirect costs and costs due to lost leisure time are major contributors to the total societal costs. The comprehensive quantification of costs of crashes will inform decision makers formulating policies that improve the safety of cyclists leading to reductions in the economic burden on society.

Accident rates amongst regular bicycle riders in Tasmania, Australia.

PURPOSE: To characterise the demographics, cycling habits and accident rates of adult cyclists in Tasmania. METHODS: Volunteers ≥18 years of age who had cycled at least once/week over the previous month provided information on demographics; cycling experience; bicycles owned; hours/km/trips cycled per week; cycling purpose; protective equipment used; and major (required third-party medical treatment or resulted ≥1 day off work) or minor (interfered with individuals' regular daily activities and/or caused financial costs) accidents while cycling. RESULTS: Over 8-months, 136 cyclists (70.6% male) completed the telephone survey. Mean (standard deviation) age was 45.4 (12.1) years with 17.1 (11.4) years of cycling experience. In the week prior to interview, cyclists averaged 6.6 trips/week (totalling 105.7km or 5.0h). The most common reason for cycling was commuting/transport (34% of trips), followed by training/health/fitness (28%). The incidence of major and minor cycling accidents was 1.6 (95% CI 1.1-2.0) and 3.7 (2.3-5.0) per 100,000km, respectively. Male sex was associated with a significantly lower minor accident risk (incidence rate ratio=0.34, p=0.01). Mountain biking was associated with a significantly higher risk of minor accident compared with road or racing, touring, and city or commuting biking (p<0.05). CONCLUSIONS: Physical activity of regular cyclists' exceeds the level recommended for maintenance of health and wellbeing; cyclists also contributed substantially to the local economy. Accident rates are higher in this sample than previously reported in Tasmania and internationally. Mountain biking was associated with higher risks of both major and minor accidents compared to road/racing bike riding.