I need to keep up with my Mind Hacks posts! A few days ago, Vaughan stumbled upon a case study in a medical journal describing a stroke patient who lost control of his hand. He ended up with "alien hand syndrome" in which his hand apparently engaged in public masturbation outside of his control. From Mind Hacks:
We tend to think of the cognitive impairments after brain injury as the most disabling - things like loss of memory or speech or language impairment, but we often neglect what we might call social impairments.Involuntary masturbation in alien hand syndrome
Especially when the effect is embarrassing, these can have just as strong an impact because many people massively restrict their lives to prevent causing social discomfort to themselves or others.