Letizia Concari

Differential Patterns of Hypoperfusion in Subtypes of Mild Cognitive Impairment

In this study the regional cerebral blood flow (rCBF) pattern of three Mild Cognitive Impairment (MCI) subtypes was measured with SPECT in 60 patients (nineteen with an amnestic deficit, sixteen with disexecutive deficits, and twenty five with mild multidomain deficits) and compared with that of 15 healthy matched older adults. The amnestic MCI subgroup showed significant hypoperfusion in the left hippocampus, parahippocampal gyrus and fronto-parieto-temporal areas. The disexecutive subgroup had significant hypoperfusion of the left superior, medial frontal and cingulate cortex. The multidomain subgroup had similar perfusion deficits to the amnestic subgroup, with an additional deficit in the left posterior cingulate gyrus. This study found differential patterns of hypoperfusion in MCI subtypes. Since all patients who progressed to dementia converted to probable Alzheimer’s disease, the different rCBF patterns most likely reflect the neuropathological heterogeneity at onset and differences in disease stage.

Visuo-spatial imagery impairment in posterior cortical atrophy: a cognitive and SPECT study.

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.

Italian norms for the Freedman version of the Clock Drawing Test

Background: The Clock Drawing Test (CDT) is a valid screening tool for the evaluation of cognitive decline. This study aimed to compute standardized norms for the Freedman version of the CDT in a population of 248 healthy Italian individuals aged from 20 to 89 years. Method: The effects of age, education, and gender on performance were assessed. Three conditions were administered: free-drawn clock (FD), which required participants to draw the contour, numbers, hands, and center of the clock; predrawn clock (PD), in which numbers, hands, and center had to be included in a predrawn contour; examiner-drawn clock (ED), in which only hands and center had to be inserted in a template including a predrawn contour and numbers. Scores for each of the single conditions and a total score were calculated. Results: Age had no effect on the FD condition, whereas a significant effect of age was found for the PD and ED conditions and the total score. Gender and education had no influence on any of the scores. Correction grids, cutoffs, and equivalent scores were computed. Conclusion: Standardized norms for the Freedman version of the CDT were collected in a large sample of healthy individuals. No adjustments were required for scores on the free-drawn condition, whereas raw scores on the predrawn and examiner-drawn conditions and the total score needed adjustments to account for age effects. The availability of standardized norms for this version of the CDT could increase the use of this comprehensive tool in the detection of dementia.

Influence of APOE status on lexical-semantic skills in mild cognitive impairment.

This study characterized the relationship between apolipoprotein E (APOE) status and residual semantic abilities in amnestic mild cognitive impairment (MCI). APOE status (ε4 carrier/non ε4 carrier) was determined in 30 amnestic MCIs and in 22 healthy matched non ε4 carrier controls. The lexical characteristics (age of acquisition, typicality, familiarity) of words produced in a category fluency task were determined. MCIs produced fewer words than controls and these were also earlier acquired and more familiar. The words produced by MCI ε4 carriers were earlier acquired than those of non ε4 carriers. Analyses limited to the first 10 words produced by patients and controls showed similar findings and also revealed that MCI subgroups retrieved first more typical words than controls. Follow up showed higher conversion to Alzheimers disease (AD) in MCI ε4 carriers than in non ε4 carriers. These findings show that a significant proportion of phenotype variability in performance on category fluency in people at increased AD risk is influenced by genetic factors. These findings explain why category fluency deficits, together with episodic memory deficits, are the only consistent early deficits in MCI patients who convert to AD.

The Qualitative Scoring MMSE Pentagon Test (QSPT): A New Method for Differentiating Dementia with Lewy Body from Alzheimer’s Disease

The differential diagnosis across different variants of degenerative diseases is sometimes controversial. This study aimed to validate a qualitative scoring method for the pentagons copy test (QSPT) of Mini-Mental State Examination (MMSE) based on the assessment of different parameters of the pentagons drawing, such as number of angles, distance/intersection, closure/opening, rotation, closing-in, and to verify its efficacy to differentiate dementia with Lewy Body (DLB) from Alzheimers disease (AD). We established the reliability of the qualitative scoring method through the inter-raters and intra-subjects analysis. QSPT was then applied to forty-six AD and forty-six DLB patients, using two phases statistical approach, standard and artificial neural network respectively. DLB patients had significant lower total score in the copy of pentagons and number of angles, distance/intersection, closure/opening, rotation compared to AD. However the logistic regression did not allow to establish any suitable modeling, whereas using Auto-Contractive Map (Auto-CM) the DLB was more strongly associated with low scores in some qualitative parameters of pentagon copying, i.e. number of angles and opening/closure and, for the remaining subitems of the MMSE, in naming, repetition and written comprehension, and for demographic variables of gender (male) and education (6–13 years). Twist system modeling showed that the QSPT had a good sensitivity (70.29%) and specificity (78.67%) (ROC-AUC 0.74). The proposed qualitative method of assessment of pentagons copying used in combination with non-linear analysis, showed to be consistent and effective in the differential diagnosis between Lewy Body and Alzheimer’s dementia.

Degenerative jargon aphasia: Unusual progression of logopenic/phonological progressive aphasia?

Primary progressive aphasia (PPA) corresponds to the gradual degeneration of language which can occur as nonfluent/agrammatic PPA, semantic variant PPA or logopenic variant PPA. We describe the clinical evolution of a patient with PPA presenting jargon aphasia as a late feature. At the onset of the disease (ten years ago) the patient showed anomia and executive deficits, followed later on by phonemic paraphasias and neologisms, deficits in verbal short-term memory, naming, verbal and semantic fluency. At recent follow-up the patient developed an unintelligible jargon with both semantic and neologistic errors, as well as with severe deficit of comprehension which precluded any further neuropsychological assessment. Compared to healthy controls, FDG-PET showed a hypometabolism in the left angular and middle temporal gyri, precuneus, caudate, posterior cingulate, middle frontal gyrus, and bilaterally in the superior temporal and inferior frontal gyri. The clinical and neuroimaging profile seems to support the hypothesis that the patient developed a late feature of logopenic variant PPA characterized by jargonaphasia and associated with superior temporal and parietal dysfunction.

The Progression of Alzheimer’s Disease: Are Fast Decliners Really Fast? A Four-Year Follow-Up

Background: The rate of cognitive and functional decline in Alzheimer’s disease (AD) changes across individuals. Objectives: Our purpose was to assess whether the concept of “fast decline” really fits its definition and whether cognitive and functional variables at onset can predict the progression of AD. Methods: 324 AD patients were included. We retrospectively examined their Mini-Mental State Examination (MMSE) total score and sub-items, Activities of Daily Living (ADL), and Instrumental Activities of Daily Living (IADL) at baseline and every six months for a 4-year follow-up. Patients were divided into “fast decliners” (n = 62), defined by a loss ≥5 points on the MMSE score within the first year from the baseline; “intermediate decliners” (n = 37), by a loss ≥5 points after the first year and before the 18th month; or “slow decliners” (n = 225), composed of the remaining patients. Results: At baseline, the groups did not differ on demographic, clinical, and cognitive variables. The decline at the end of the 4-year follow-up period seems to be similar among the different decline clusters. Predictors of disease progression have not been identified; only the MMSE total score at 12 months <14/30 was indicative of a poor prognosis. Conclusions: Even with the limitation due to the small sample size, the lack of differences in the disease progression in time in the different clusters suggest the inconsistency of the so-called “fast decliners”. This study was unable to show any significant difference among clusters of AD progression within a 4-year time interval. Further studies should better clarify whether a more consistent distinction exists between slow and fast decliners.

Recovery from transient global amnesia following restoration of hippocampal and fronto – cingulate perfusion

A patient who suffered a transient global amnesia (TGA) attack underwent regional cerebral blood flow (rCBF) SPECT imaging and neuropsychological testing in the acute phase, after one month and after one year. Neuropsychological testing in the acute phase showed a pattern of anterograde and retrograde amnesia, whereas memory was within age normal limits at follow up. SPECT data were analysed with a within subject comparison and also compared with those of a group of healthy controls. Within subject comparison between the one month follow up and the acute phase detected increases in rCBF in the hippocampus bilaterally; further rCBF increases in the right hippocampus were detected after one year. Compared to controls, significant hypoperfusion was found in the right precentral, cingulate and medial frontal gyri in the acute phase; after one month significant hypoperfusion was detected in the right precentral and cingulate gyri and the left postcentral gyrus; after one year no significant hypoperfusion appeared. The restoration of memory was paralleled by rCBF increases in the hippocampus and fronto-limbic-parietal cortex; after one year neither significant rCBF differences nor cognitive deficits were detectable. In conclusion, these data indicate that TGA had no long lasting cognitive and neural alterations in this patient.

Neuropsychological predictors of conversion in mild cognitive impairment

Parkville, Australia; Mental Health Research Institute, Melbourne, Australia; Edith Cowan University, Perth, New York, Australia; CogState Ltd, Melbourne, Australia; University of Melbourne, Melbourne, VIC, Australia; Austin Hospital, Melbourne, Australia; National Ageing Research Institute Inc. (NARI), Melbourne, Australia; Austin Health, Melbourne, Australia; Austin Hospital, Heidelberg, VIC, Australia; St Georges Hospital, Kew, Australia; Mental Health Research Institute, Perth, Australia. Contact e-mail: c.restrepo@student.unimelb.edu.au

Specific semantic memory deficits and neurofunctional alterations in Mild Cognitive Impairment

AFQT scores than MCI-discordant pairs; MCI-discordant pairs had lower scores than normal-concordant pairs. Within-pair AFQT differences were observed only in dizygotic discordant pairs; normal twins scored higher. Overall results were similar for age 55 AFQT even after adjusting for age 20 scores. Conclusions: Neuropsychologically-defined MCI is present in the sixth decade of life (50s) in non-clinically referred, community-dwelling adults. A unique feature of the discordant twin design enabled us to identify unobserved heterogeneity. The subgroups of normal twins are phenotypically the same, but differed in premorbid cognitive ability based on genetic risk (i.e., having a normal or MCI co-twin). Differences based on genetic risk for the MCI phenotypes followed the same pattern. Premorbid ability is not the entire story, however, because differences persist even after adjusting for premorbid ability. Finally, genetic influences cannot cause differences in genetically-identical monozygotic twins. Therefore, the fact that premorbid cognitive differences within discordant pairs were accounted for by only dizygotic twins suggests that the link between premorbid cognitive ability and MCI is due to some degree of shared genetic influences.