The Tower of London Test: different scoring criteria for diagnosing Alzheimer's disease and mild cognitive impairment

The Tower of London (TOL) is used for evaluating planning skills, which is a component of the executive functions. Different versions and scoring criteria were developed for this task, and some of them present with different psychometrical properties. This study aimed to evaluate two specific scoring methods of the TOL in diagnosing Mild Cognitive Impairment and probable Alzheimer's disease. The TOL total scores from 60 patients of each diagnosis were compared with the performance of 60 healthy-aged controls using receiver operating characteristics analysis and multinomial logistic regression. Krikorian method better diagnosed Alzheimer's disease, while Portellas's was better at discriminating healthy controls from Mild Cognitive Impairment, but were not efficient at comparing this last group with Alzheimer's patients. Regression analysis indicates that in addition to screening tests, TOL improves the classification of the three groups. The results suggest the two scoring methods used for this task may be useful for different diagnostic purposes.     

The utility of the spatial span in a clinical geriatric population

Spatial Span subtest of the Wechsler Memory Scale has been viewed as an indicator of working memory and visuospatial processing. The current study examined the impact of cognitive impairment and its severity on Spatial Span performance. A neuropsychological battery including Spatial Span was administered to 538 individuals (65-89) who were grouped by consensus into Alzheimer's disease, Vascular Dementia, Amnestic Mild Cognitive Impairment, Non-Amnestic Mild Cognitive Impairment and cognitively normal. Increase in level of impairment resulted in a decrease in Spatial Span Total Score. A weak relationship between age and Spatial Span Total Score was found. Spatial Span Forward remains relatively stable regardless of level of impairment. Spatial Span Backward was more sensitive to severity. No significant differences were found between individuals diagnosed with Alzheimer's disease and those with Vascular Dementia suggesting similar deficit patterns in the cognitive abilities measured by the Spatial Span. Mild Cognitive Impairment groups and normals did not differ suggesting visuospatial processes are not affected early in the dementing process.     

Performance on a measure of category fluency in cognitively impaired elderly

Measures of verbal fluency are widely used in the assessment of cognitive functioning of the elderly. However, limited research has evaluated patterns (across specific timed intervals) of performance on tasks of language fluency in different forms of dementia. The current study investigated semantic fluency in 488 elderly individuals (249 with Alzheimer's dementia, 97 Vascular dementia, 97 Mild Cognitive Impairment and 45 cognitively intact) across 15-second intervals in an animal naming task using retrospective chart review. Normal controls produced significantly more exemplars and AD patients produced fewer animal names than the other groups. After the first 15- second time interval, the demented groups produced significantly fewer exemplars than the non-demented. At the end of 30 seconds it was possible to differentiate normal aging from MCI who no longer differed from the VaD group. Overall, it appears that the greatest and most clinically meaningful differences between the diagnostic groups were detected in the first three 15-second intervals. The present findings support the use of time intervals and total scores on tasks of verbal fluency in clinical settings and for research purposes.     

Memory factors in Rey AVLT: Implications for early staging of cognitive decline

Supraspan verbal list learning is widely used to assess dementia and related cognitive disorders where declarative memory deficits are a major clinical sign. While the overall learning rate is important for diagnosis, serial position patterns may give insight into more specific memory processes in patients with cognitive impairment. This study explored these patterns in a memory clinic clientele. One hundred eighty three participants took the Rey Auditory‐Verbal Learning Test (RAVLT). The major groups were patients with Alzheimer's disease (AD), Vascular Dementia (VD), Mild Cognitive Impairment (MCI), and Subjective Cognitive Impairment (SCI) as well as healthy controls (HC). Raw scores for the five trials and five serial partitions were factor analysed. Three memory factors were found and interpreted as Primacy, Recency, and Resistance to Interference. AD and MCI patients had impaired scores in all factors. SCI patients were significantly impaired in the Resistance to Interference factor, and in the Recency factor at the first trial. The main conclusion is that serial position data from word list testing reflect specific memory capacities which vary with levels of cognitive impairment.     

Preliminary evidence for impaired rapid verb generation in schizophrenia

It has been hypothesized that nouns and verbs are processed within relatively separable semantic memory networks. Although abnormal semantic processing is a common feature of schizophrenia-spectrum disorders, no prior studies have specifically examined the comparability of noun and verb generation deficits in schizophrenia. In the current study, verb (action), noun (animal), and letter (f) fluency performance was evaluated in 22 inpatients with schizophrenia and 27 healthy comparison subjects. On average, individuals with schizophrenia performed approximately one standard deviation below the healthy comparison subjects on action, animal, and letter fluency. Action fluency-but not letter or animal fluency-was moderately correlated with tests of working memory, response inhibition, semantic memory, and cognitive flexibility. Findings suggest that verb- and noun-based fluency deficits are of comparable severity in schizophrenia, but that the impairment in verb generation may be driven by different underlying cognitive mechanisms. Further, hypothesis-driven research on the nature and extent of verb network disruption in schizophrenia appears warranted.     

Performance on a measure of category fluency in cognitively impaired elderly

ABSTRACT

Measures of verbal fluency are widely used in the assessment of cognitive functioning of the elderly. However, limited research has evaluated patterns (across specific timed intervals) of performance on tasks of language fluency in different forms of dementia. The current study investigated semantic fluency in 488 elderly individuals (249 with Alzheimer's dementia, 97 Vascular dementia, 97 Mild Cognitive Impairment and 45 cognitively intact) across 15-second intervals in an animal naming task using retrospective chart review. Normal controls produced significantly more exemplars and AD patients produced fewer animal names than the other groups. After the first 15- second time interval, the demented groups produced significantly fewer exemplars than the non-demented. At the end of 30 seconds it was possible to differentiate normal aging from MCI who no longer differed from the VaD group. Overall, it appears that the greatest and most clinically meaningful differences between the diagnostic groups were detected in the first three 15-second intervals. The present findings support the use of time intervals and total scores on tasks of verbal fluency in clinical settings and for research purposes.     

Movements execution in amnestic mild cognitive impairment and Alzheimer's disease

We evaluated the relationship between motor and neuropsychological deficits in subjects affected by amnestic Mild Cognitive Impairment (aMCI) and early Alzheimer's Disease (AD). Kinematics of goal-directed movement of aMCI and AD subjects were compared to those of age-matched control subjects. AD showed a slowing down of motor performance compared to aMCI and controls. No relationships were found between motor and cognitive performances in both AD and aMCI. Our results suggest that the different motor behaviour between AD and aMCI cannot be related to memory deficits, probably reflecting the initial degeneration of parietal-frontal circuits for movement planning. The onset of motor dysfunction in early AD could represent the transition from aMCI to AD.     

Verb deficits in Alzheimer's disease and agrammatism: implications for lexical organization

This study examined the nature of verb deficits in 14 individuals with probable Alzheimer's Disease (PrAD) and nine with agrammatic aphasia. Production was tested, controlling both semantic and syntactic features of verbs, using noun and verb naming, sentence completion, and narrative tasks. Noun and verb comprehension and a grammaticality judgment task also were administered. Results showed that while both PrAD and agrammatic subjects showed impaired verb naming, the syntactic features of verbs (i.e., argument structure) influenced agrammatic, but not Alzheimer's disease patients' verb production ability. That is, agrammatic patients showed progressively greater difficulty with verbs associated with more arguments, as has been shown in previous studies (e.g., Kim & Thompson, 2000; Thompson, 2003; Thompson, Lange, Schneider, & Shapiro, 1997), and suggest a syntactic basis for verb production deficits in agrammatism. Conversely, the semantic complexity of verbs affected PrAD, but not agrammatic, patients' performance, suggesting "bottom-up" breakdown in their verb lexicon, paralleling that of nouns, resulting from the degradation or loss of semantic features of verbs.     

Patterns of semantic memory impairment in Mild Cognitive Impairment

Although the semantic memory impairment has been largely documented in Alzheimer's disease, little is known about semantic memory in the preclinical phase of the disease (Mild Cognitive Impairment). The purpose of this study was to document the nature of semantic breakdown using a battery of tests assessing different aspects of conceptual knowledge: knowledge about common objects, famous people and famous public events. Results indicate that all domains of semantic memory were impaired in MCI individuals but knowledge about famous people and famous events was affected to a greater extent than knowledge about objects. This pattern of results suggests that conceptual entities with distinctive and unique properties may be more prone to semantic breakdown in MCI. In summary, results of this study support the view that genuine semantic deficits are present in MCI. It could be useful to investigate the etiological outcome of patients failing or succeeding at such tests.     

Action verbal fluency normative data for the elderly

An emerging body of literature points to the prominent role of the frontal lobes in the retrieval of verbs, whereas production of common and proper nouns arguably is mediated primarily by posterior and anterior temporal regions, respectively. Although the majority of studies examining the neuroanatomic distinctions between verb and noun retrieval have relied on action naming tasks (naming depicted activities, e.g., running) as indicators of verb retrieval abilities, recent studies have utilized an action (verb) verbal fluency measure, the Action Fluency Test (AFT), to assess verb retrieval. Findings from these studies suggest that action fluency is sensitive to the integrity of fronto-subcortical neural circuitry and that it is a valid measure of executive and language functions. The AFT is an easily administered executive function measure, but no normative data for the AFT or other action fluency tasks has been published. This study was undertaken to provide initial AFT normative data for a sample of 145 healthy elderly subjects. As education is significantly correlated with AFT scores, the normative data are stratified by educational level.     

Diagnosis of cognitive impairment onset in older adults based on limitations in language skills / Diagnóstico del inicio del deterioro cognitivo en mayores a partir de limitaciones en las capacidades lingüísticas

Abstract

Progressive decline in language has been described in neuropsychological studies on Alzheimer’s disease and Mild Cognitive Impairment (MCI). We investigate this decline in its early stages, as well as its manifestations and the linguistic differences between participants at risk of developing MCI and without impairment. Participants were 36 older adults, all aged over 65. They were assessed using 31 subtests grouped into eight areas: fluency, comprehension, oral expression, reading, writing, memory, perceptual organization and processing speed. Our results showed significant differences between participants at risk of developing MCI and without impairment in verbal tests but not in manipulative tests. All participants at risk of developing MCI scored lowest in these eight areas. Our findings illustrate the relevance of investigating language skills in people at risk of developing MCI. Investigating these neuropsychological changes will help design appropriate intervention programmes that affect areas with higher levels of impairment.     

Chronic stress, cognitive functioning and mental health

This review aims to discuss the evidence supporting the link between chronic stress, cognitive function and mental health. Over the years, the associations between these concepts have been investigated in different populations. This review summarizes the findings that have emerged from older populations as well as from populations suffering from pathological aging, namely Mild Cognitive Impairment and Alzheimer's Disease. Although older adults are an interesting population to study in terms of chronic stress, other stress-related diseases can occur throughout the lifespan. The second section covers some of these stress-related diseases that have recently received a great deal of attention, namely burnout, depression, and post-traumatic stress disorder. Given that chronic stress contributes to the development of certain pathologies by accelerating and/or exacerbating pre-existing vulnerabilities that vary from one individual to the other, the final section summarizes data obtained on potential variables contributing to the association between chronic stress and cognition.     

Focused attention deficits in patients with Alzheimer's disease and mild cognitive impairment

Reaction time (RT) tasks take various forms, and can assess psychomotor speed, (i.e., simple reaction time task), and focused attention (i.e., choice reaction time (CRT) task). If cues are provided before stimulus presentation (i.e., cued choice reaction time (CCRT) task), then a cueing effect can also be assessed. A limited number of studies have addressed the nature of focused attention impairments in Alzheimer's disease (AD). Additionally, it is unknown whether similar impairments occur in Mild Cognitive Impairment (MCI). The current study used three RT tasks to address the nature of focused attention impairments in AD and MCI subjects. The results suggest that there were significant CRT and CCRT differences in AD subjects when compared to NECs. Furthermore, slowed RTs were also present in the MCI group, which provides evidence for impaired focussed attention and the inability to benefit from a cue in both the MCI and AD groups. The implications of the impairments related to the MCI group could potentially prove useful in early diagnosis of cognitive impairments in the elderly.     

Lexical decision in sentences: Effects of syntactic structure

A lexical decision paradigm was used to examine syntactic influence on word recognition in sentences. Initial fragments of sentences were presented visually (CRT display) one word at a time (at reading speeds), from left to right. The string terminated with the appearance of a lexical decision target. The grammatical structure of the incomplete sentence affected lexical decision reaction time (RT). In Experiment 1, modal verb contexts followed by main verb targets and preposition contexts followed by noun targets produced lower RTs than did the opposite pairings (i.e., modal/noun and preposition/verb). In Experiment 2, transitive verb contexts followed by noun targets and subject noun phrase contexts followed by verb targets yielded lower RTs than did the opposite pairings. Similar contrasts for adjective targets did not yield comparable effects in Experiment 2, but did when the adjective was the head of a predictable phrase (Experiment 4). In Experiment 3, noun targets yielded lower RTs than did verb targets after contexts of a transitive verb followed by a prepositional phrase. An account of these effects is offered in terms of parsing constraints on phrasal categories.     

轻度认知功能障碍的防治决策

轻度认知功能障碍(mild cognitive i mpairment,MCI)被认为是阿尔茨海默病(alzhei mer disease,AD)的极早期。AD的防治需从MCI开始,早期发现,早期干预,以便延缓和阻止AD的发生。目前我国MCI具有就诊率低,诊断率低,治疗率低和漏诊率高的特点。临床研究要改变MCI三低一高的状况,医师及民众要提高对MCI的认识,应该采取重在预防,重视筛查,早期诊断,早期治疗的决策,可以延迟和阻止AD的发生。     

Semantic context influences memory for verbs more than memory for nouns

Three experiments revealed that memory for verbs is more dependent on semantic context than is memory for nouns. The participants in Experiment 1 were asked to remember either nouns or verbs from intransitive sentences. A recognition test included verbatim sentences, sentences with an old noun and a new verb, sentences with an old verb and a new noun, and entirely new sentences. Memory for verbs was significantly better when the verb was presented with the same noun at encoding and at retrieval. This contextual effect was much smaller for nouns. Experiments 2 and 3 replicated this effect and provided evidence that context effects reflect facilitation from bringing to mind the same meaning of a verb at encoding and at retrieval. Memory for verbs may be more dependent on semantic context because the meanings of verbs are more variable across semantic contexts than are the meanings of nouns.     

The return of “visiting relatives”: Pragmatic effects in sentence processing

Two experiments were performed to investigate the role of syntactic and pragmatic cues on the disambiguation of noun phrases of the form VERB+ing NOUN+s, like visiting relatives, that can be interpreted as either singular or plural noun phrases. Both experiments used a self-paced reading task in which reading times were measured for two words, a verb and an adverb, immediately following the potentially ambiguous noun phrase. The interpretation of the noun phrase as singular or plural was biased by pragmatic cues in the first experiment and by syntactic cues in the second experiment. In both experiments, subjects were faster to read the adverb following the verb when the interpretation biased by the cues agreed in number with the verb that immediately followed the target noun phrase than when it did not agree with the verb. These results suggest that pragmatic cues, like syntactic cues, can be utilized rapidly in sentence processing.     

Paired associate learning of action verbs with visual-or motor-imaginal encoding instructions

Summary It is suggested that visual-imaginal encoding of actions, i.e., imagining seeing somebody else performing a described action, should be distinguished from motor-imaginal encoding, i.e., imagining how one performs the action oneself. While both kinds of encoding should provide good item-specific information, only visual-imaginal encoding should also lead to good relational encoding of word pairs. In three experiments in which subjects had to learn verb pairs, we obtained supporting data for this assumption. Although CR performance was equal to FR performance under visual-imaginal encoding, under motorimaginal encoding CR performance was worse than FR performance. In principle, this finding parallels results obtained with imagined noun pairs and with performed verb pairs.The research reported here was supported by a grant from the Deutsche Forschungsgemeinschaft to J. Engelkamp and Hubert D. Zimmer. The paper was prepared during a stay of these authors at the Centre d'Études de Psychologie Cognitive, enabled by a grant of PROCOPE 311 pro     

Grammatical category ambiguity in aphasia

This study asked whether aphasic adults show different noun/verb retrieval patterns based upon their clinical categorization as fluent or nonfluent. Participants selected either the noun or the verb meaning of target words, as presented in three contexts. The framework was that nouns (associated with temporal lobe function) are processed, stored, and retrieved separately from verbs (associated with frontal lobe function), implying separate status in the mental lexicon. Stimuli were homophonic homographs, words that are spelled and pronounced the same but which have different meanings (in this case, noun and verb meanings). Another contrast was the putative difference between systematic pairs (e.g., "kiss" and "farm"), in which noun and verb meanings are transparently related, and may be stored as a unit, and unsystematic pairs (e.g., "squash" and "sink"), in which noun and verb meanings are apparently unrelated, implying discrete storage. Results demonstrated significant interactions between fluent and nonfluent participants, suggesting that, as expected, fluent aphasic adults have more difficulty with nouns, nonfluent aphasic adults have more difficulty with verbs. There was no effect of systematicity. Contrary to expectations, verbs proved less vulnerable, rather than more vulnerable, to aphasic impairment.     

Noun verb dissociation in Parkinson's disease

A noun/verb dissociation with a relative verb deficit was found in patients affected by Parkinson's disease, even in relatively early stages, when mental deterioration is not severe. This finding is compatible with earlier observations, according to which verbs are dealt with in more anterior regions with respect to nouns. It also supports the speculation that the co-ordination and the manipulation of information associated with a verb world rely on the frontostriatal system.