The impression that I got from looking at a couple of articles on alien hand syndrome was that it was an extremely common or basically guaranteed result of getting a callosotomy to treat severe epilepsy. However, I just ran into a study that showed essentially no effect from being born without a corpus callosum:
The pattern of anatomical features of the brain revealed by magnetic resonance imaging (MRI) is described in six patients incidentally identified as having acallosal brains... Conventional clinical testing revealed no abnormalities except a slight impairment of walking heel-to-toe in two patients. None of the patients had subjective restrictions of activities of daily life, which shows the efficacy of unknown compensatory processes.
- How common is alien hand syndrome?
- How frequently do callosotomies result in alien hand syndrome?
- How often is there severe damage to the corpus callosum unaccompanied by alien hand syndrome?
- How many cases of alien hand syndrome are there with no visible damage to the corpus callosum?