Acquired epileptic aphasia (AEA, or Landau-Kleffner syndrome) is a unique c
ondition in which children can lose oral language (OL) comprehension and ex
pression for a prolonged period. These children can benefit from visual for
ms of language, mainly sign language (SL), but the quality of SL has never
been analyzed. The case is reported here of a boy with AEA who lost speech
comprehension and expression from 3 years 6 months to 7 years and was educa
ted in SL from the age of 6 years. His SL was evaluated at the age of 13 ye
ars and 6 months and compared with a control child with congenital sensorin
eural deafness. It was found that: (1) our patient achieved the same profic
iency in SL as the control child with deafness; (2) SL learning did not com
pete with, but perhaps even hastened, the recovery of OL. Intact ability to
learn a new linguistic code such as SL suggests that higher-order language
areas were preserved and received input from a separate visual route, as s
hown by neuropsychological and functional imaging research in deaf and hear
ing signers.