LANGUAGE AND MEMORY ASSESSMENT: Rebecca Rausch (far right), now a senior neurologist at the University of California, Los Angeles, is pictured here performing a modified version of the Wada test in the early 1970s. The patient is a candidate for epilepsy surgery to remove tissue from the brain hemisphere causing seizures. The test is required to determine if brain areas that underlie language and memory also reside in the same side of the brain. During the test, the patient names and recalls objects shown to him while an anesthetic—usually sodium amobarbital—is introduced to each hemisphere in turn. If linguistic deficits coincide with the anesthetization of the seizure-causing area, surgery will not be performed.© UCLAAs a medical student on the Japanese island of Hokkaido in the 1940s, Juhn Wada developed an interest in neurology, before “neurology” was formally a word and before dedicated departments existed anywhere in Japan. After completing his degree, Wada began researching electroconvulsive (“shock”) therapy, which works by inducing seizures—abnormal electrical activity in the brain. At that time, the procedure was becoming common for patients with severe depression or schizophrenia. The shocks, however, also caused language and memory impairments. Based on existing evidence showing that linguistic and, to a lesser extent, memory functioning predominantly take place in a single brain hemisphere, Wada proposed anesthetizing that hemisphere to avoid causing the impairments.
His proposed approach was highly criticized until 1948, when Wada learned of a patient who had developed persistent, uncontrollable seizures—a young cook at an American base camp who had been shot in the head by a drunken soldier attempting to shoot off his hat. As a last resort, the cook agreed to let Wada anesthetize his brain, one hemisphere at a time. Upon the injection of an anesthetic barbiturate into an artery known to deliver blood only to the left hemisphere, the man’s seizures were successfully controlled. But the side effects of the barbiturate treatment were startling and immediately apparent. According to his written account, chills ran up and down Wada’s spine as the patient temporarily lost all language ability and motor function on the ...
