Two careful reviews in the Annals of Medicine review current trial evidence.  This is a hard topic to study because interventions are heterogeneous; outcomes are multiple and vary between studies, and long-term follow-up is required. As far as exercise is concerned, the evidence is simply insufficient. Cognitive training reduces cognitive decline in the particular cognitive task targeted by the training, but does not seem to produce a global effect. These studies were both based on people with normal functioning at baseline.
— Richard Lilford, CLAHRC WM Director
- Brasure M, Desai P, Davila H, Nelson VA, Calvert C, Jutkowitz E, et al. Physical Activity Interventions in Preventing Cognitive Decline and Alzheimer-Type Dementia: A Systematic Review. Ann Intern Med. 2018; 168: 30-8.
- Butler M, McCreedy E, Nelson VA, Desai P, Ratner E, Fink HA, et al. Does Cognitive Training Prevent Cognitive Decline?: A Systematic Review. Ann Intern Med. 2018; 168: 63-8.
Head impacts seem to be a common occurrence in American Football, with studies of youth players suggesting they experience around 240-252 impacts per season.  In the previous News Blog we looked at research on brain injury in ex-American Football players, which found widespread chronic traumatic encephalopathy. Now a cross-sectional study by Alosco, et al. has looked at the impact playing from an early age has on behaviour, mood and cognition. The authors assessed 214 former amateur and professional football players (who hadn’t played any other contact sport) on a number of psychiatric tests. Multivariate regression analysis showed that those who had begun playing before the age of 12 had at least twice the risk of significant impairments in behavioural regulation, apathy and executive function, and three times the risk for clinically elevated depression, compared with those who were began playing when they were 12 or older. These effects were not linked to age, education or even how long the individual played football for. There were also no differences in the level of play, i.e. those who played professional fared similar to those who only played at high school-level. The authors hypothesise that 12 years old is a critical time for key neurodevelopmental milestones that occur within the hippocampus and amygdala (where clinical functions such as emotion regulation and behaviour are modulated).
— Peter Chilton, Research Fellow
- Munce TA, Dorman JC, Thompson PA, Valentine VD, Bergeron MF. Head impact exposure and neurologic function of youth football players. Med Sci Sports Exerc. 2015; 47: 1567–76.
- Cobb BR, Urban JE, Davenport EM, Rowson S, Duma SM, Maldjian JA et al. Head impact exposure in youth football: elementary school ages 9-12 years and the effect of practice structure. Ann Biomed Eng. 2013; 41: 2463–73.
- Lilford RJ. Two Hundred and Two Ex-(American) Footballers’ Brains Analysed After Death – This You Must Read. NIHR CLAHRC West Midlands News Blog. 15 September 2017.
- Alosco ML, Kasimis AB, Stamm JM, et al. Age of first exposure to American football and long-term neuropsychiatric and cognitive outcomes. Transl Psychiatry. 2017; 7: e1236.