EXTINCTION PHENOMENON IN HEMIPLEGIA

ROUTINE sensory examinations are usually carried out with the method of single stimulation. This appears to be adequate, but it does not always reveal existing defects in sensibility. For example, one cutaneous region of the body may be sentient to a single stimulus. However, this very point thus tested may become insentient when it and a point in a homologous region on the opposite side are simultaneously stimulated. Thus, with the method of double simultaneous stimulation there occurs a disappearance, or "extinction," of sensation from a part of the body which is not anesthetic on routine examination. 1 This "extinction" is not always complete, for at times the patient reports dulling, or "obscuration," rather than complete disappearance of sensation. The various aspects of the phenomena of extinction and obscuration have been discussed in previous communications. 2 It was shown that extinction occurs oftenest in patients with lesions implicating the sensory