Hyperlexia and ambient echolalia in a case of cerebral infarction of the left anterior cingulate cortex and corpus callosum

Abstract

We report the case of a 69-year-old woman with cerebral infarction in the left anterior cingulate cortex and corpus callosum. She showed hyperlexia, which was a distinctive reading phenomenon, as well as ambient echolalia. Clinical features also included complex disorders such as visual groping, compulsive manipulation of tools, and callosal disconnection syndrome. She read words written on the cover of a book and repeated words emanating from unrelated conversations around her or from hospital announcements. The combination of these two features due to a focal lesion has never been reported previously. The supplementary motor area may control the execution of established subroutines according to external and internal inputs. Hyperlexia as well as the compulsive manipulation of tools could be interpreted as faulty inhibition of preexisting essentially intact motor subroutines by damage to the anterior cingulate cortex reciprocally interconnected with the supplementary motor area.

Keywords:

• Hyperlexia
• Ambient echolalia
• Anterior cingulate cortex
• Corpus callosum
• Cerebral infarction

We thank Yukari Sakuma, an occupational therapist, and Sachiko Fujikawa, a speech therapist, for their help in performing the neuropsychological tests, and Dr. Masami Takatsu and Professor Dr. Masahiro Abo for their valuable advice.