Alien Control

Abstract

In the previous chapter, and in accordance with contemporary views, I distinguished between anarchic and alien hand, both in terms of symptomatology and the neurological pathology underlying their respective symptoms. Anarchic hand, you will recall, is considered to be a motorform disorder. Patients with lesions to the anterior corpus callosum tend to exhibit contralaterial (to the dominant hemisphere) anarchic hand in the form of inter-manual conflict, whereas patients with additional damage to the medial premotor cortex (the SMA) engage in what Biran et al. (2006) refer to as exo-evoked actions (movements triggered by environmental or exogenous factors). Such damage leads to compulsive tool manipulation that is, again, typically contralateral to the hemisphere in which the (unilaterial) damage occurs. Importantly, as far as this chapter is concerned, in neither form of the disorder do patients fail to recognize the anarchic hand as their own. They may deny willing the hand to act and claim that it acts as if it has a will of its own (and so moves contrary to their intentions), but they never deny ownership of the hand or claim the hand is controlled by some other alien source.