Pure agraphia with topographical disorientation caused by right hemisphere lesion

ABSTRACT. Memory problems are common in stroke patients, although little is known about how accurately chronic stroke patients can monitor and control memory processes. Objective: The performance of memory and metamemory in stroke patients and healthy controls were investigated, as well as dissociation between performances. Methods: 10 adults with right hemisphere lesion (mean [M] age=53.2 [SD=9.7]), 10 with left hemisphere lesion (M age=60.4 [SD=6.6]) and 20 healthy participants (M age=56.5 [SD=9.3] with no neurological disease, matched for sex, age and years of education participated in a multiple-case design study. Participants completed a metamemory experimental paradigm, as well as immediate and delayed word recall and recognition tasks. Results: Data indicated that 10 out of the 20 patients presented significantly lower scores compared to controls, two of which had global deficits (functional association). Functional dissociations between memory monitoring (judgments of learning, JOL), control (allocation of study time) and capacity (cued-recall task) among patients were found for eight cases, suggesting these processes are independent. Conclusion: These findings reveal stroke patients may have specific metamemory impairment and can contribute to the understanding of cognitive models of metamemory processing.

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Visuo-Spatial Imagery Impairment in Posterior Cortical Atrophy: A Cognitive and SPECT Study

Behavioural Neurology ◽

10.1155/2011/547451 ◽

2011 ◽

Vol 24 (2) ◽

pp. 123-132 ◽

Cited By ~ 22

Author(s):

Simona Gardini ◽

Letizia Concari ◽

Salvatrice Pagliara ◽

Caterina Ghetti ◽

Annalena Venneri ◽

...

Keyword(s):

Autobiographical Memory ◽

Semantic Memory ◽

Mental Imagery ◽

Spatial Representation ◽

Right Hemisphere ◽

Cortical Atrophy ◽

Precentral Gyrus ◽

Posterior Cortical Atrophy ◽

Spatial Imagery ◽

Topographical Disorientation

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.

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