My knee-jerk reaction to this is, "Another useless confusion of correlation and causation! Stupid media! Stupid HN!" But... A family friend had a stroke. It a

My knee-jerk reaction to this is, "Another useless confusion of correlation and causation! Stupid media! Stupid HN!" But... A family friend had a stroke. It affected his gate and speech. He found that if he smiled broadly, both his gate and speech became more fluid. This suggests that the act of smiling can change function of the rest of the nervous system. So who knows?