Affiliations: Department of Neuroscience, University of Parma,
Parma, Italy | Outpatient Clinic for the Diagnosis and Therapy of
Cognitive Disorders, AUSL, Parma, Italy | Struttura di Fisica Sanitaria, Azienda Ospedaliera
Universitaria, Parma, Italy | Clinical Neuroscience Centre, University of Hull,
United Kingdom and S. Camillo Hospital (I.R.C.C.S), Venice, Italy
Note: [] Address for correspondence: Paolo Caffarra M.D., Dementia Unit,
Department of Neuroscience, University of Parma, Via Gramsci, 14, 43100 Parma,
Italy. Tel./Fax: +39 0521 704116; E-mail: [email protected]
Abstract: This study investigated the cognitive profile and the cerebral
perfusion pattern in a highly educated 70 year old gentleman with posterior
cortical atrophy (PCA). Visuo-perceptual abilities, spatial memory, spatial
representation and navigation, visuo-spatial mental imagery, semantic and
episodic-autobiographical memory were assessed. Regional cerebral blood flow
(rCBF) was imaged with SPECT. Cognitive testing showed visual-perceptual
impairment, apperceptive visual and landmark agnosia, topographical
disorientation with way-finding deficits, impaired map learning and poor mental
image generation. Semantic memory was normal, while episodic-autobiographical
memory was impaired. Reduced rCBF was found mainly in the right hemisphere, in
the precentral gyrus, posterior cingulate and middle temporal gyri, cuneus and
precuneus, in the left superior temporal and lingual gyri and in the
parahippocampus bilaterally. Hypoperfusion in occipito-parietal regions was
associated with visuo-spatial deficits, whereas deficits in visuo-spatial
mental imagery might reflect dysfunction related to hypoperfusion in the
parahippocampus and precuneus, structures which are responsible for spatial and
imagery processing. Dissociating performance between preserved semantic memory
and poor episodic-autobiographical recall is consistent with a pattern of
normal perfusion in frontal and anterior temporal regions but abnormal rCBF in
the parahippocampi. The present findings indicate that PCA involves
visuo-spatial imagery deficits and provide further validation to current
neuro-cognitive models of spatial representation and topographical
disorientation.
