Alexandra Economou

Nonepisodic memory deficits in amnestic MCI

ObjectiveTo (a) compare patients with amnestic Mild Cognitive Impairment (MCI), mild Alzheimer disease (AD), and a group of healthy elderly persons on nonepisodic memory measures; (b) examine which measures are independent of level of education in the groups studied. BackgroundEpisodic memory impairment is a cardinal feature of preclinical AD. However, a number of other cognitive measures are also sensitive to the preclinical stage of AD and deficits in multiple domains characterize AD several years before clinical diagnosis. Materials and MethodsPatients with amnestic MCI (N=31), patients with mild probable AD (N=15), and healthy elderly controls (N=27) were compared on nonepisodic memory tasks measuring fluid intelligence, working memory, processing speed, verbal fluency, and visual-perceptual and motor functions. Amnestic MCI patients were selected based on clinical criteria and a subgroup was also selected based on psychometric criteria. ResultsMultivariate analyses of covariance, controlling for the effects of age, education, and sex, showed that fluid intelligence, working memory, processing speed, semantic fluency, visual-perceptual function, and complex motor function were significantly worse in the MCI than the elderly control group. Working memory, processing speed, semantic fluency, and complex motor tasks were significantly worse in the mild probable AD than the MCI group. The analyses were corroborated using the psychometrically derived MCI group. Conclusions(a) Performance on multiple nonepisodic memory measures is affected in the preclinical stage of AD, indicating that broad cognitive impairment characterizes that stage. (b) Complex motor tasks were independent of level of education in our sample, and may have practical utility in the early detection of dementia.

The breakdown of functional categories in Greek aphasia: Evidence from agreement, tense, and aspect

Background: Verbal inflectional errors are among the most prominent characteristics of aphasic nonfluent speech. Several studies have shown that such impairment is selective: subject–verb agreement is relatively intact while tense is severely impaired. A number of researchers view the deficit as structural and attribute errors to a breakdown of functional categories and their projections. Agrammatic individuals are thought to produce trees that are intact up to the Tense node and “pruned” from this node up. A partial preliminary report of the data was presented at the “Science of Aphasia V” conference in Potsdam in 16–21 September 2004. An earlier version of this paper was presented at the Departmental Seminars of the Department of Language and Communication Science at City University (February 2005) and appeared at the Reading Working Papers in Linguistics 6 (2005). We thank two anonymous reviewers for comments on an earlier version of this paper as well as the two reviewers of Aphasiology for their useful comments and suggestions. We also thank speech pathologists M. Diamanti, A. Xofillis, and M. Moudouris for referring the patients. Note: All co‐authors have contributed equally to this article. Aims: The present study investigates (a) the relative sensitivity of functional categories related to verbal inflection in Greek aphasia and the systematicity thereof; and (b) the relation between patterns of impairment in production and grammaticality judgements. Method & Procedures: We present results from a sentence completion and a grammaticality judgement task with seven Greek‐speaking aphasic individuals and seven control participants matched for age and education. Materials were constructed to assess three functional categories: subject–verb agreement, tense, and aspect. Eight verbs were used, balancing estimated familiarity and regularity of aspectual conjugation. Outcomes & Results: A great variability was observed among participants in overall performance but the pattern of performance was quite systematic. The results indicated that inflectional morphemes are not all impaired to the same degree in Greek aphasia. In both tasks, as a group, patients made more errors in aspect than in agreement. The group differences between tense and the other two conditions did not reach statistical significance. Moreover, a comparison of individual aphasic performance in the three functional categories indicated that in every case in which statistically significant differences were observed among the three functional categories, agreement was found to be less impaired than tense, aspect, or both. Conclusions: These findings do not support a global impairment of inflectional morphemes in aphasia but support a selective one and, in particular, a dissociation between agreement, on the one hand, and tense and/or aspect, on the other hand. Moreover, our findings do not support a hierarchical account along the lines of Friedmann and Grodzinsky (1997) but are compatible with Chomskys (2000) Minimalist Program and with Wenzlaff and Clahsens (2004) tense underspecification theory.

Olfactory identification in elderly Greek people in relation to memory and attention measures

The University of Pennsylvania Smell Identification Test (UPSIT) and the Cross-Cultural Smell Identification Test (CC-SIT) were administered to nondemented Greek participants ranging in age from 49 to 88 years together with tests of verbal memory from the Wechsler Memory Scale-3rd Edition (WMS-III). The test scores of the sample administered the CC-SIT were compared with the test scores of the 12 analogous UPSIT items of the sample administered the UPSIT. The percent of individuals correctly identifying each of the odorants of the UPSIT and CC-SIT is reported, together with means and standard deviations (S.D.) of the total smell scores. UPSIT performance in both the full test and the 12 analogous items was associated with WMS-III Logical Memory I performance after accounting for the effects of age, education and gender. CC-SIT performance was associated with gender, score on the Beck Depression Inventory-II and Logical Memory I performance. The study shows that olfactory identification is associated with verbal memory in nondemented individuals after accounting for demographic variables.

Are memory deficits dependent on the presence of aphasia in left brain damaged patients

While memory deficits in aphasia have been reported in several studies, it has been suggested that these deficits are not due to the presence of aphasia, but rather to the left hemisphere lesion per se. In order to investigate this hypothesis, we tested 64 aphasic and 15 non-aphasic patients with left brain damage on verbal and visuospatial span tasks. Analyses revealed lower than expected performance on all four primary memory tasks for the aphasic, but not for the non-aphasic group. Moreover, comparison of the three lesion-location groups (posterior, anterior, and global) did not reveal statistically significant differences. The present data show that aphasic patients demonstrate memory deficits, which are not specific to the verbal modality, and contradict the notion that primary memory impairment is not due to the presence of aphasia, but rather to a lesion in the left hemisphere per se. Overall our study suggests that verbal and visuospatial, primary memory deficits in patients with left hemisphere lesions are possibly dependent on the presence of aphasia, but not on lesion location or lesion size.

Memory score discrepancies by healthy middle-aged and older individuals: the contributions of age and education.

The aim of this study was to examine discrepancies between immediate/delayed recall and recall/working memory in middle-aged and older persons by age and education. Participants were 322 healthy individuals from the community who were stratified into three age and three education groups. Immediate and delayed recall distributions of WMS-III Logical Memory (LM) scores approximated normal curves, and LM savings scores showed a significant, but small, effect of age. LM (immediate, delayed) and Letter-Number Sequencing (LNS) discrepancies varied as a function of age and education. The difference between LM and LNS was not significant in the younger and less educated participants, but increased with age in the most educated group, and in the oldest group LNS exceeded LM (immediate and delayed). The results indicate deterioration in encoding and retrieval, rather than storage, with age, and show a differential, but small, effect of age and education on the memory measures. Working memory was resistant to age-related decline relative to immediate and delayed recall in the oldest, most educated group. Delayed recall-working memory discrepancy is relatively stable with age and education and may be a useful index of the onset of memory pathology across different ages and levels of education.

Working-Delayed Memory Difference Detects Mild Cognitive Impairment Without Being Affected by Age and Education

Performance on neuropsychological tests is affected by age and education, which makes the early detection of cognitive impairment difficult when assessing individuals of varying levels of education. We examined the effects of age, education, and gender on three memory indexes of the Wechsler Memory Scale-III, Delayed Memory, Working Memory and the difference between Working-Delayed Memory in a sample of patients with amnestic Mild Cognitive Impairment, patients with mild probable Alzheimers disease, and a nondemented elderly comparison group. Whereas Delayed and Working Memory scores were affected by participant type, age, and education, the Working-Delayed Memory difference score was affected by participant type, only. Our preliminary conclusions, pending replication of the findings with a larger sample, are that working-delayed memory difference was sensitive to early memory decline without being affected by age and education. Parts of the data were presented at the 2nd Hellenic Interdisciplinary Conference of Alzheimers Disease and Related Disorders, Thessaloniki, Greece, January 2002. We thank Margarita Sarri for assistance with psychometric assessments, Emy Sarafidou for statistical advice and three anonymous reviewers for comments on an earlier version of this paper. Sokratis Papageorgiou is currently at the University of Athens Department of Neurology.

Episodic Memory in Alzheimer Disease, Frontotemporal Dementia, and Dementia With Lewy Bodies/Parkinson Disease Dementia: Disentangling Retrieval From Consolidation.

Introduction:Differences in episodic memory performance in patients with Alzheimer disease (AD), frontotemporal dementia (FTD), dementia with Lewy bodies (DLB)/Parkinson disease with dementia (PDD) are inconsistent and task dependent. The inconsistencies may be attributed to the different tasks drawing on different memory processes. Few studies have examined episodic memory impairment in the above groups using memory tests that facilitate encoding, to distinguish memory deficits due to impairment of specific processes. Methods:We examined the memory performance of 106 AD patients, 51 FTD patients, 26 DLB/PDD patients, and 37 controls using the Five-Words Test, a 5-item memory test that facilitates encoding. Results:The patient groups did not differ in modified Mini Mental State Examination scores. AD patients scored lowest on the Five-Words Test overall, and showed the greatest reduction from immediate total recall to delayed free recall relative to the other 2 groups, consistent with a predominantly consolidation deficit. DLB/PDD patients showed the largest improvement from delayed free to delayed total recall relative to the other 2 groups, consistent with a predominantly retrieval deficit. Discussion:Deficits in both consolidation and retrieval underlie the memory impairment of the patients, to different extents, and contribute to the theoretical understanding of the nature of the memory impairment of the patient groups.

The 5 Objects Test: a novel, minimal-language, memory screening test

Very brief screening tests are useful in primary care, but may show reduced sensitivity in detecting Alzheimer’s disease or other dementias in the early stages and may show an education or age bias. We examined the reliability, validity, sensitivity, specificity and relationship with demographic variables of a novel, very brief memory screening test that makes limited language demands. Participants were 452 neurological patients with different diagnoses and a community-dwelling sample of 119 middle-aged and older controls. The 5 Objects Test requires the recall of the locations of five everyday objects, immediately after placement and after a brief period of time. The test was unaffected by age and education and showed good reliability and discriminant validity. In receiver operating characteristic (ROC) analyses, specificity was high across a range of sensitivities in all four main comparisons (AD cases versus controls; all dementia cases versus controls; memory-impaired versus non memory-impaired patients; MCI cases versus controls), and sensitivity was lowest in differentiating MCI cases from controls. The test showed similar areas under the ROC curve to the much longer modified Mini Mental State Examination. The 5 Objects Test is a reliable and valid very brief screening test that is suitable for primary care. Because of its limited linguistic demands, the test is appropriate for persons with limited language use or from different linguistic backgrounds.

Self-awareness of cognitive efficiency: Differences between healthy elderly and patients with mild cognitive impairment (MCI)

ABSTRACT Introduction: Self-estimation of performance implies the ability to understand one’s own performance with relatively objective terms. Up to date, few studies have addressed this topic in mild cognitive impairment (MCI) patients. The aim of the present study was to compare objective measures of performance with subjective perception of specific performance on cognitive tests and investigate differences in assessment between MCI patients and healthy elderly. Method: Thirty-five participants diagnosed with MCI (women = 16, men = 19, mean age = 65.09 years ±SD = 7.81, mean education = 12.83 years ±SD = 4.32) and 35 control subjects similar in terms of age and education (women = 20, men = 15, mean age = 62.46 years ± SD = 9.35, mean education = 14.26 ± SD = 2.84) were examined with an extended battery of neuropsychological tests. After every test they were asked to self-evaluate their performance by comparing it to what they considered as average for people of their age and educational level. This self-evaluation was reported on a scale ranging from –100 to +100. Results: Significant differences were found in the self-assessment patterns of the two groups in memory measures of verbal and visual delayed recall, visuospatial perception, and tests of attention. MCI patients overestimated their performance on every cognitive domain while control participants underestimated their performance on measures of verbal memory. Conclusions: The present results indicate that accuracy of self-report is not uniform across groups and functional areas. The discrepancies in the MCI patients indicate unawareness of their memory deficits, which is contradictory to subjective memory complaints as being an important component for clinical diagnosis.

Patterns of cognitive and fine motor deficits in a case of Dandy-Walker continuum.

Cerebellar vermian hypoplasia in the context of Dandy-Walker complex is a relatively common disorder associated with a variety of cognitive and behavioral deficits in addition to impairment in motor control. Few studies, however, have examined the neuropsychological profiles of children with isolated hypoplasias of the cerebellum. Herein, we report a 6-year-old girl with Dandy-Walker continuum presenting with mild mental retardation and an inability to produce intelligible speech, despite adequate comprehension of single items and simple instructions. She was able to articulate vowels but not consonants, and fine motor function was deficient. Visual memory was intact for single items but not for multiple items, and visuospatial perception was impaired. An inability to form intelligible speech is not typically reported in cases of isolated vermian hypoplasia. The case extends our knowledge of the phenotypes associated with cerebellar hypoplasia and its relation to fine motor and articulatory control.