Progressive peripheral agraphia

We describe RW, a patient who presented with writing difficulty that deteri orated over time. While her graphemes were typically legible, her writing w as extremely slow, and her letters were written in an inconsistent and hete rogeneous manner (e.g. each 'a' in the word 'banana' was produced in a diff erent way). Her mental imagery of letters was impoverished, and she also pr oduced allographic errors in her writing. She had some spelling errors as w ell, but many of these were due to omissions, perseverations, and motor ope rations. A positron emission tomography scan demonstrated superior parietal occipital and superior frontal defects that were more evident on the left than the right. Our observations are consistent with the hypothesis that RW has a deficit retrieving physical letter forms as manifested by her hetero geneous and slow production of letter forms. This disruption of grapheme re trieval is associated with interruption of a superior frontal-parietal syst em in the left hemisphere.