Patient J.W. suffered a concussive head trauma at age 13, after which he began to have brief absence spells that went untreated. At 19, he experienced his first grand mal seizure. The frequency of the seizures increased and were intractable with medication. In 1979, when he was 26 years old, he underwent a two-stage callosotomy.[86] Immediately following both surgeries, his right hemisphere had the capacity to understand spoken and written language, meaning that he had a right hemisphere semantic system, but was unable to speak. For example, the left hand could make a picture-word correspondence: Lateralize a picture of a bird to J.W.'s right hemisphere and his left hand would point to the written word "bird." Lateralize the word "zebra" to his right hemisphere and his left hand would point to a picture of a zebra.[87] Unexpectedly eleven years later, while evaluating visual field stabilizing equipment, J.W.'s right hemisphere started to vocally name pictures that were presented to his right hemisphere.[88] Over the following several years, this ability continued to increase.[89] Up until then, the previously reported post-callosotomy dynamic periods of right hemisphere language capacity suggested that the right hemisphere could only develop language skills in the absence of the left hemisphere when there had been damage to the left hemisphere in childhood.[90] Another interpretation of the data was that observations of right hemisphere language development were restricted by the limited life span of postoperative adult patients.[91] J.W. was the first split-brain patient to demonstrate an increasing ability for right hemisphere speech many years after his callosotomy. While long-term functional plasticity has been suggested in adults, documentation of such is scarce.[88]