A longitudinal case study of a patient with a progressive
loss of meaning of objects with preserved phonology and
syntax is presented. Repeated measures of language, praxis,
visual cognition, and semantic processing were carried
out. The patient still has preserved conversational speech,
social skills, and orientation in her 8th year of her illness,
but shows severe anomia and comprehension deficit in all
modalities of stimulus presentation. In addition to standardized
tests of language, cognition, and memory, specific experiments
of categorization, modalities of word access, item consistency,
category specificity, and definition of words were carried
out. Results indicate a frequency dependent loss of meaning
that was consistent in all modalities and throughout all
object categories. However, the relative preservation of
visual categorization of all categories tested and the
language based categorization of animals suggested some
fractionation of semantic memory. Relative preservation
of autobiographical and personal memories versus
semantic memory was a striking observation. Evidence for
selective impairment of central semantic processing was
obtained from experiments indicating item consistency of
loss and the lack of semantic cuing. Neuroimaging evidence
of left temporal lobe atrophy and the classical picture
is compatible with similar cases published under the term
semantic dementia or “transcortical sensory aphasia
with visual agnosia” and suggest the diagnosis of
Pick's disease. (JINS, 1998, 4,
388–398.)
Brain Activation During Reading in Deep Dyslexia: An MEG Study
