Anecdotal accounts suggest that individuals spontaneously synchronize their movements to the 'beat' of background music, often without intending to, and perhaps even without attending to the music at all. However, the question of whether intention and attention are necessary to synchronize to the beat remains unclear. Here, we compared whether footsteps during overground walking were synchronized to the beat when young healthy adults were explicitly instructed to synchronize (intention to synchronize), and were not instructed to synchronize (no intention) (Experiment 1: intention). We also examined whether reducing participants' attention to the music affected synchronization, again when participants were explicitly instructed to synchronize, and when they were not (Experiment 2: attention/intention). Synchronization was much less frequent when no instructions to synchronize were given. Without explicit instructions to synchronize, there was no evidence of synchronization in 60% of the trials in Experiment 1, and 43% of the trials in Experiment 2. When instructed to synchronize, only 26% of trials in Experiment 1, and 14% of trials in Experiment 2 showed no evidence of synchronization. Because walking to music alters gait, we also examined how gait kinematics changed with or without instructions to synchronize, and attention to the music was required for synchronization to occur. Instructions to synchronize elicited slower, shorter, and more variable strides than walking in silence. Reducing attention to the music did not significantly affect synchronization of footsteps to the beat, but did elicit slower gait. Thus, during walking, intention, but not attention, appears to be necessary to synchronize footsteps to the beat, and synchronization elicits slower, shorter, and more variable strides, at least in young healthy adults.

Background Homeless and precariously housed individuals experience a high burden of comorbid illnesses, and excess mortality. Cross-sectional studies report a high rate of cognitive impairment. Long-term trajectories have not been well investigated in this group. Aims To longitudinally assess risks for premature and/or accelerated cognitive ageing, and the relationship with early mortality in homeless and precariously housed people. Method This is a 9-year community-based study of 375 homeless and precariously housed individuals from Vancouver, Canada. Annual cognitive testing assessed verbal learning and memory, and inhibitory control. Linear mixed-effects models examined associations between clinical risk factors (traumatic brain injury, psychotic disorders, viral exposure, alcohol dependence) and cognitive change over 9 years. Cox regression models examined the association between cognition and mortality. Results Traumatic brain injury and alcohol dependence were associated with decline in verbal memory. Inhibitory control declined, independent of risk factors and to a greater extent in those who died during the study. Better inhibitory control was associated with a 6.6% lower risk of mortality at study entry, with a 0.3% greater effect for each year of life. For each one-point increase in the Charlson Comorbidity Index score at study entry, the risk of mortality was 9.9% higher, and was consistent across age. Adjusting for comorbidities, inhibitory control remained a significant predictor of mortality. Conclusions Findings raise the possibility of a premature onset, and accelerated trajectory, of cognitive ageing in this group of homeless and precariously housed people. Traumatic brain injury, alcohol dependence and cognition could be treatment priorities.

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Objective: Homeless and marginally housed youth are particularly vulnerable members of society, and are known to experience numerous health problems, including psychiatric illness, substance use, and viral infection. Despite the presence of these risk factors for cognitive compromise, there is limited research on the cognitive functioning of homeless and marginally housed youth. The present study examines the degree and pattern of cognitive impairment and associations with key risk factors in a sample of marginally housed young adults.Method: Participants (N = 101) aged 20–29 years old were recruited from single-room occupancy hotels, and underwent cognitive, psychiatric, neurological, and serological assessments.Results: Forty percent of participants were identified as mildly cognitively impaired across multiple domains, and 16% were moderately-severely impaired. Deficits in memory and attention were most prevalent, while impairments in inhibitory control/processing speed and cognitive flexibility were also present but tended to be less severe. Developmental and historical factors (premorbid intellectual functioning, neurological soft signs, earlier exposure to and longer duration of homelessness or marginal housing), as well as current health risks (stimulant dependence and hepatitis C exposure), were associated with cognitive impairment.Conclusions: The strikingly high rate of cognitive impairment in marginally housed young adults represents a major public health concern and is likely to pose a significant barrier to treatment and rehabilitation. These results suggest that the pathway to cognitive impairment involves both developmental vulnerability and modifiable risk factors. This study highlights the need for early interventions that address cognitive impairment and risk factors in marginalized young people.

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