Verbal fluency in dementia of frontal lobe type and dementia of Alzheimer type

Instruments de mesure et échelles d’évaluation utilisés dans la démence fronto-temporale

In frontotemporal dementia (FTD), evaluation scales and measurement instruments are less codified than in Alzheimer's disease. Some nonspecific scales are available, two of which are very useful for early diagnose of the disease: Lebert and Pasquier's Frontotemporal Behavioral Scale (FBS) to assess behavioral disturbances and Dubois's Frontal Assessment Battery (FAB) to assess executive ability. However, these scales do not contain enough items to follow up FTD. The main scale used to follow up the disease is the Neuropsychiatric Inventory (NPI). The Frontal Behavioural Inventory (Kertesz) seems to be interesting, but has not yet been validated in France. The Mattis Dementia Rating Scale, not specific for FTD, is used to assess the cognitive rate. The activities of daily living scales and caregiver burden are not well known in FTD.

Word List Generation Performancein Alzheimer's Disease and Vascular Dementia

Word list generation (WLG) was examined among clinical samples of individuals with Alzheimer's disease (AD) (n = 73) or ischemic vascular dementia (IVD) (n = 85), equivalent in age, education, current and estimated premorbid intellectual functioning, and proportion of men and women. The AD group performed significantly better than did the IVD group on lexical WLG, and a trend was observed indicating superior performance among the IVD group on categorical WLG. Within-groups, comparisons of group means, and profile analyses of individual performance patterns all indicated that persons with AD demonstrated a lexical > categorical pattern significantly more often than did IVD participants. The absolute difference in average performance between the AD and IVD groups on lexical and categorical WLG was small; the findings, however, generally support the clinical utility of the lexical > categorical WLG pattern in the differential diagnosis of AD and IVD. The patterns of performance support the presence of relative impairment in semantic processing among the individuals with AD and global deficits in retrieval and processing speed in individuals with IVD.

Alzheimer's disease and frontal variant of frontotemporal dementia-- a very brief battery for cognitive and behavioural distinction

The aim of this study was to investigate whether a brief neuropsychological battery consisting of a limited number of cognitive tests and an evaluation of the behavioural domains intended to discriminate between frontotemporal dementia (fv-FTD) and Alzheimer's disease (AD), constitutes a useful instrument for making a differential clinical diagnosis between these two pathologies. Nineteen fv-FTD and 39 AD patients were compared on cognitive tasks (assessing memory, executive functions, language and constructional praxis) and on the NPI behavioural assessment. A stepwise discriminant analysis was performed to identify the linear combination of cognitive and behavioural measures able to best discriminate between the two groups. One test for each of the investigated cognitive domains (Delayed Prose Recall, FAS verbal fluency, Boston naming test, Rey's Figure A Copy) and the four subscales of the Neuropsychiatry Inventory (NPI) which best differentiated between fv-FTD and AD patients (apathy, disinhibition, euphoria, aberrant motor behaviour) were used. The analysis selected Rey's Figure A Copy, FAS verbal fluency and NPI apathy subscale as the best discriminants between fv-FTD and AD patients. The final equation assigned 73.7% of the fv-FTD patients and 94.7% of the AD patients to the correct diagnostic group. A validation study conducted on a new independent sample of 11 fv-FTD and 22 AD patients confirmed the high sensitivity (82.6 %) and specificity (81.8%) of the diagnostic equation in assigning fv-FTD and AD patients to the correct dementia group. Although both cognitive and behavioural differences exist between FTD and AD, previous studies have aimed at differentiating the two pathologies by considering the two aspects separately and discriminant analyses were focused only on neuropsychological or neuropsychiatric evaluations. The present results emphasise the importance of rating both cognitive and behavioural clinical features of the two syndromes as objectively as possible to improve differential diagnostic accuracy.

Semantic and phonemic sequence effects in random word generation: a dissociation between Alzheimer's and Huntington's disease patients

Alzheimer's disease (AD) patients perform worse on category than letter fluency tasks, while Huntington's disease (HD) patients show the reverse pattern or comparable impairment on both tasks. We developed a random word generation task to further investigate these deficits. Twenty AD and 16 HD patients and 20 elderly and 16 middle-aged controls guessed which of three pictures (hat, cat, or dog) landed on a die's top face sixty times. Three consecutive response pairings were possible: semantic (cat-dog), phonemic (hat-cat), and neutral (hat-dog). Since healthy individuals avoid repeating meaningful associates ("repetition avoidance"), an increased pairing frequency reflects processing deficits. AD patients produced more semantic and HD patients more phonemic pairings compared to their respective control groups, indicating selective semantic and phonemic processing deficits in AD and HD patients, respectively.

Patterns of memory impairment and perseverative behavior discriminate early Alzheimer's disease from subcortical vascular dementia

Previous research suggests that the neuropsychological deficits in Alzheimer's disease (AD) are different from that of vascular dementia (VaD), especially with respect to memory, language and executive functions, but negative findings were reported. Our objective was to clarify the cognitive syndrome in AD and VaD in the early stage of these disorders. We investigated 45 patients with early AD, 23 patients with subcortical VaD and 35 normal controls. All subjects were assessed with neuropsychological battery designed to measure memory, language, praxis and executive functions. Patients with AD had significantly worse scores on Story Recall (p<0.02) and on all measures of the Free and Cued Selective Reminding Test (p<0.03 to 0.001) than did patients with VaD, as well as greater number of perseverations (p<0.02) on category fluency. Conversely, VaD patients had more perseverations (p<0.02) on the Modified Card Sorting Test. Despite the similar degree of overall cognitive deterioration, the findings show more impaired retrieval from long-term storage in AD than in VaD. Moreover, the data suggest that AD and subcortical VaD affect perseverative behavior in a different fashion. These results may be helpful in differentiating AD from VaD in the early stage of these disorders, when mental impairments are not pervasive yet.

Object naming and semantic fluency among individuals with genetic risk for Alzheimer's disease

OBJECTIVES

This study longitudinally examined the object naming and semantic fluency of individuals who are at risk for developing Alzheimer's disease (AD) by virtue of having APOE-4 or a family history of AD.

METHODS

A total of 108 participants (40 with a family history of AD and 43 with APOE-4) completed the Boston Naming Test and the Animal Naming task at initial assessment and after two years.

RESULTS

At baseline, object naming was significantly lower for those with both risk factors, F(2, 99) = 5.72, p < 0.01, but those with either risk factor had significantly lower scores at follow-up, F(2, 99) = 3.41, p < 0.05. Semantic fluency (animal naming) was reduced among subjects with the APOE-4 allele at baseline, F(1, 100) = 4.02, p < 0.05, but it was not associated with either risk factor at follow-up.

CONCLUSIONS

These deficits may be associated with a prodromal risk for AD and may serve as pre-symptomatic markers for the development of AD.

Neurocognitive profiles in elderly patients with frontotemporal degeneration or major depressive disorder

Major depressive disorder (MDD) and frontotemporal dementia (FTD) are both disorders in elderly populations that involve the prefrontal cortex and appear to have similar neurocognitive deficits. This review examined whether there are testable deficits in cognition that are consistent across individuals within the same neuropathological condition that could be used to facilitate early diagnoses. Medline and PsychInfo databases were searched for cognitive studies of depressed and FTD patients that used a matched control group and reported findings with means and standard deviations (N = 312). Effect sizes for FTD patients with mild and moderately advanced disease were compared to effect sizes within subgroups of depressed patients, such as inpatients, outpatients and community volunteers. Moderately advanced FTD patients were more impaired than depressed patients over all domains, particularly in language ability, although depressed inpatients appeared similar to FTD patients in some domains. Effect sizes for FTD patients who were in the mild, or early, stage of the disease (MMSE = 28) were similar to those of depressed outpatients but slightly worse than those of community volunteers in all domains except semantic memory and executive ability. In the latter two domains, even mild FTD patients had notably large deficits. All FTD patients showed more severe deficits in some domains relative to other domains. In contrast, depressed patients tended to vary by clinical presentation or disease severity, but the magnitude of impairment for each subgroup remained relatively consistent across domains and they did not have the severe focal deficits in one or two domains demonstrated by FTD patients.

Deficit of preparatory attention in frontotemporal dementia

We studied preparatory attention in patients suffering from frontotemporal dementia in the beginning stages of the disease, using an experimental test developed by LaBerge, Auclair, and Siéroff (2000). In this experimental test, a distracter can appear while subjects have to prepare to respond to a simple target. The probability that a distracter can appear in a trial is varied across three blocks. Normal controls show an increase of response times to targets (slope) as a function of the distracter probability, preparatory attention to the target is reduced by the increase of the distracter probability. Patients suffering from frontotemporal dementia show a slope of response times which is more than twice as large as the slope obtained by their matched controls. Such an abnormal increase of response times to targets is interpreted as a deficit in preparatory attention. Patients also show more omissions than controls. We suggest that this deficit in preparatory attention is related to the frontal lesion presented by the patients and can result in higher distractibility, a symptom frequently encountered in these patients.

Pick Complex: an integrative approach to frontotemporal dementia: primary progressive aphasia, corticobasal degeneration, and progressive supranuclear palsy

BACKGROUND

Frontotemporal dementia (FTD) is a new label for clinical Pick's disease (PiD) because the eponymic term is increasingly restricted to the pathologic finding of Pick bodies. This restriction created the impression that PiD is rare and that is it difficult to diagnose. FTD is also a term most often used for behavioral and personality alterations. Primary progressive aphasia (PPA) and corticobasal degeneration (CBD), formerly the extrapyramidal variety of PiD, are also part of the syndrome. Recently, chromosome 17 localization and tau mutations were discovered in familial forms of the disease.

REVIEW SUMMARY

FTD consists of behavioral and personality changes, often beginning with apathy and disinterest, which may be mistaken for depression. Disinhibition and perseverative, compulsive behavior often appear at the same time. A quantifiable frontal behavioral inventory is useful in the diagnosis beyond a checklist. The second type of presentation is progressive language loss (PPA). A less common variety is semantic dementia: the meaning of nouns and objects is lost. As the disease progresses, all components tend to overlap. CBD and progressive supranuclear palsy (PSP), although described as distinct entities, show a great deal of clinical, pathologic, genetic, and biochemical overlap. The evidence suggests they also belong to the complex. The association of motor neuron disease (MND) with FTD and other varieties of the complex is also reviewed.

CONCLUSIONS

Clinical Pick's disease or Pick Complex includes the overlapping syndromes of FTD, PPA, CBD, PSP, and FTD-MND. The neuropathological and genetic spectrum should be viewed with emphasis on the commonalities rather than the differences, allowing the recognition of the relatively high frequency of this presenile syndrome.

Selection Ability in Alzheimer's Disease: Investigation of a Component of Semantic Processing

Selection ability (selecting a response from several competing semantic and/or lexical representations) was tested in 21 participants with Alzheimer's disease (AD) and 28 control participants to help clarify the nature of semantic impairments in AD. Selection demands were manipulated in 3 tasks (lexical fluency, comparison, and verb generation). In each, high-selection conditions required response selection from competing alternatives, whereas low-selection conditions had a reduced need for selection. Patients with AD were disproportionately impaired on the high-selection conditions of all tasks, even when this condition was easier. Selection deficits on verb generation were evident only relative to nonspeeded controls. Overall results indicate impaired semantic selection abilities in AD, which may contribute to poor performance on some semantic tasks.

Categorization of object descriptions in Alzheimer's disease and frontotemporal dementia: limitation in rule-based processing

Studies of semantic memory in probable Alzheimer's disease (AD) have focused on the degradation of semantic knowledge, but other work in AD suggests an impairment in the semantic categorization processes that operate on this knowledge. We examined the categorization of object descriptions, where semantic category membership judgments were based on rule-based or similarity-based categorization processes. We found that AD patients were selectively limited in their semantic categorization under conditions requiring a rule-based approach. However, AD patients did not differ from healthy seniors under conditions based on judgments of overall similarity. We showed that this was not due to nonspecific or overall task-related difficulty associated with the rule condition by asking the subjects to use similarity-based judgments of perceptually degraded versions of the stimuli. The results of this condition did not differ from other similarity-based judgments but did differ from the rule-based condition in AD. Rule-based judgments of semantic category membership correlated with executive measures of inhibitory control and mental search, but not with measures of episodic memory or overall dementia severity, suggesting a contribution of executive resources to rule-based semantic categorization. Moreover, the pattern of limited rule-based categorization in AD closely resembled the performance profile of patients with frontotemporal dementia, further implying that executive resource limitations underlie AD patients' limited rule-based semantic categorization. These findings suggest that semantic memory difficulty in AD is due in part to a deficit in executive processes that are central to rule-based categorization in semantic memory.

Frontotemporal dementia: patient characteristics, cognition, and behaviour

OBJECTIVES

To describe sociodemographic data of patients with frontotemporal dementia (FTD), to compare the cognitive profile of patients with FTD with that of severity-matched patients with Alzheimer's disease using the CERAD neuropsychological battery (CERAD-NP), to investigate the frequency of behavioural disturbances, and to examine the relation between FTD-specific non-cognitive behavioural symptoms of patients with FTD with age and sex.

METHODS

Fifty outpatients were diagnosed with FTD according to the Lund-Manchester consensus criteria. Cognitive impairment was assessed in 30 patients using the CERAD-NP. Severity of dementia was rated on the Clinical Dementia Rating (CDR). Eleven non-cognitive symptoms were rated by severity. To compare CERAD-NP results between patients with FTD and AD, 30 patients with AD were matched for age, sex, and global severity of cognitive performance.

RESULTS

The average age at onset of first symptoms was 57.8 years. Eighteen patients (36%) had a positive family history of dementia. On the CERAD-NP patients with FTD performed significantly better than patients with AD on word list learning, delayed verbal recall and visuoconstruction (p < 0.05). There were no significant differences between FTD and AD on naming and verbal fluency tasks. The most frequent non-cognitive behavioural symptoms in FTD were loss of insight, speech abnormality, and apathy. Non-cognitive behavioural symptoms were more frequent in younger and in male than in older patients and in female patients.

CONCLUSIONS

The CERAD-NP is a valuable clinical instrument for the cognitive evaluation of patients with suspected FTD. Complementary short tests of attention and executive function may be recommended. To enhance diagnostic sensitivity informant interviews should focus on non-cognitive behavioural changes, taking advantage of standardised questionnaires.

Frontal hypometabolism does not explain inhibitory dysfunction in Alzheimer disease

A series of tasks assessing inhibitory processes was administered to patients with Alzheimer disease and control subjects. Two groups of patients with Alzheimer disease were examined: patients with hypometabolism restricted to the posterior (temporal and parietal) cerebral areas and patients with hypometabolism in both posterior and anterior (frontal) cerebral areas. The performances of the patients with Alzheimer disease were inferior to those of control subjects on all inhibitory tasks, but the two groups of patients obtained similar scores. These data indicate that frontal lobe hypometabolism is not necessary to produce inhibitory impairment in Alzheimer disease. Consequently, inhibitory dysfunction could be the consequence of a (partial) disconnection process between posterior and anterior cerebral areas.

Cognitive profiles differ in autopsy-confirmed frontotemporal dementia and AD

BACKGROUND

Frontotemporal dementia (FTD) is currently distinguished from AD primarily on the basis of behavioral features because studies of cognition have shown negligible or inconsistent differences. However, the poor discriminability of cognitive measures may relate to reliance on imprecise clinically diagnosed groups. Therefore, a retrospective examination of neuropsychological test performance in autopsy-confirmed patients is warranted.

OBJECTIVE

To compare the pattern of cognitive deficits exhibited by patients with autopsy-confirmed FTD and AD.

METHODS

The profiles of cognitive deficits exhibited by patients with neuropathologic diagnosis of FTD (n = 14) or AD (n = 28) were compared. The Mattis Dementia Rating Scale (MDRS), letter and category fluency tests, Wechsler Intelligence Scale for Children-Revised block design test, Boston naming test, and clock drawing test were administered.

RESULTS

Multivariate analysis of covariance controlling for age, education, and level of dementia revealed that patients with FTD performed significantly worse than patients with AD on letter and category fluency tests but significantly better on the MDRS memory subscale, block design test, and clock drawing test. A logistic regression model, validated in an independent clinical sample, used letter fluency, MDRS memory, and block design scores to correctly classify 91% of AD patients and 77% of FTD patients.

CONCLUSIONS

A double dissociation in the pattern of cognitive deficits exhibited by FTD and AD patients was demonstrated. The FTD patients were more impaired than AD patients on word generation tasks (i.e., verbal fluency) that are sensitive to frontal lobe dysfunction but less impaired on tests of memory and visuospatial abilities sensitive to dysfunction of medial temporal and parietal association cortices.

Executive control function in psychiatric and medical illness

Executive Control Function (ECF) is the ability to plan, sequence, and monitor one's behavior in order to accomplish a given goal while simultaneously exercising cognitive flexibility to adapt to changing task requirements. Multiple studies demonstrate that ECF predicts functional outcome, level of care required, and work potential for both well and ill populations. However, clinicians often do not routinely assess ECF during mental status evaluations because of the perceived lack of practical bedside tests. This review article discusses the major neuropsychological measures used to probe for impairment, with special emphasis on those that are easily administered at the patient's bedside. The current literature on executive dysfunction in psychiatric and medical illness is reviewed. The neuroanatomy and neurochemistry of ECF is also reviewed, with emphasis on structural dysfunction in specific illnesses. Finally, various treatment options, both pharmacological and psychotherapeutic, are discussed.

Neuropsychologische Befunde bei der Frontotemporalen Demenz

Zusammenfassung: Post-mortem Untersuchungen diagnostizieren eine Frontotemporale Demenz (FTD) in etwa 20 % aller neurodegenerativen Erkrankungen. Bei der klinischen Untersuchung wird diese schwierige Diagnose jedoch viel seltener gestellt. Die vorliegende Arbeit gibt einen Überblick über neuropsychologische Studien der FTD und versucht, den Stellenwert der Neuropsychologie zu bestimmen. Neuropsychologische Standarduntersuchungen der FTD zeigen in vielen Fällen ein relativ unspezifisches Profil mit variablen Einschränkungen bei frontal-exekutiven Leistungen, der Aufmerksamkeit, beim anterograden Gedächtnis und beim Benennen, wogegen komplexe visuell-räumliche Leistungen oft besser erhalten sind. Eine differentialdiagnostische Abgrenzung zur Alzheimer-Erkrankung (DAT) und zu anderen Demenzen gelingt in frühen und mittleren Erkrankungsstadien oft nicht befriedigend. Somit erscheint eine Diagnose der FTD unter ausschließlicher Berücksichtigung des neuropsychologischen Profils nicht möglich. Daher ist es sinnvoll, das Augenmerk vor allem auf die prominenten Verhaltensauffälligkeiten von FTD-Patienten zu legen und zusätzliche diagnostische Hilfsmittel heranzuziehen.

Single photon emission CT and positron emission tomography in the evaluation of neurologic disease

Widely available SPECT allows imaging of certain critical components of neurotransmission, providing clinically and experimentally significant information. Future efforts may be directed toward developing innovative techniques to delineate dynamic neurochemical changes in vivo.

Pattern of intrusions in verbal recall: comparison of Alzheimer's disease, Parkinson's disease, and frontal lobe dementia

Although some researchers have suggested that intrusions in word list learning are more frequent in Alzheimer's disease, recent studies have shown that this might not be true. In fact, intrusions are common in many neurological degenerative diseases. The goal of the present study was to examine the types of intrusions made by three groups of patients, namely patients with Parkinson's disease (PD), Alzheimer's disease (AD), and dementia with prominent frontal lobe semiology (FD). Although PD patients learned more words (trials 1 to 5 on the RAVLT) than the two other groups, there was no significant difference in the total number of intrusions. However, significant differences between groups were observed for nonrelated intrusions, the proportion of PD patients (15.4%) being lower than the proportion of AD (45.5%) and FD (45.8%) patients with this type of intrusions. No other type of intrusions (same category, recurring, phonemic) significantly differentiated between the three groups. The proactive interference effect (PI), measured as the difference between first recall of list A and list B recall, was stronger in PD than in the two other groups, reflecting the strong positive correlation between total number of words recalled on the RAVLT and severity of the PI effect. Prior list intrusions (intrusions from list A while recalling list B items) were significantly more pronounced in FD than in the two other groups. Finally, free associations (series of intrusions related to one another but not to the target items) were observed almost exclusively in FD patients. These findings illustrate some qualitative differences between various neurological degenerative diseases. They also stress the marked similarities between AD and FD with regards to verbal learning.

The role of tests of frontal executive function in the detection of mild dementia

OBJECTIVE

To compare the performance of patients with mild dementia (Mini Mental State Examination (MMSE) >23), depression (Montgomery-Asberg depression rating scale (MADRS) >12) and controls on tests of frontal executive function (FEF), to see if simple tools could be an adjunct to early recognition of dementia in primary care.

DESIGN

Subjects were required to score above 23 on the MMSE, and to be non-depressed unless in the depression group. Tests of FEF used were a letter based verbal fluency test, a cognitive estimates test, trail marking parts A and B, and a Stroop colour word test. Subjects were followed up at one year to assess long-term outcomes.

SETTING

The Thornhill Unit, an old age psychiatry unit, Moorgreen Hospital, Southampton, UK.

PATIENTS

Sixteen patients with a clinical diagnosis of dementia but with normal or borderline MMSE scores, 16 subjects with depression and 19 healthy control subjects.

RESULTS

Subjects with mild dementia scored significantly worse than control subjects on all FEF tests used other than verbal fluency. Subjects with mild dementia were only found to score worse than depressed subjects on the cognitive estimates test and Stroop test, with the Stroop test providing better discrimination between these groups. At follow-up, MMSE scores of both dementia and depression groups were worse.

CONCLUSIONS

Many simple tests of FEF can distinguish subjects with mild dementia from controls, although caution must be taken in the presence of depression. Of these tests, the cognitive estimates test may provide a simple test which can be used in conjunction with screening tests for dementia, such as the MMSE. The Stroop colour test was the most successful at distinguishing subjects with mild dementia from those with depression, but was more difficult to use. The depression group remained cognitively impaired at follow-up, despite improvements in depressive symptoms.

Executive control functions in degenerative dementias: a comparative review

This paper reviews the literature concerning executive control impairments in degenerative dementias. The construct of executive control functioning is examined, as is the neuroanatomy of frontal-subcortical networks, believed to underlie executive function (EF) impairments. The pattern of EF impairments in Alzheimer's disease (AD) which affects temporal and parietal brain regions most severely is contrasted with observed executive dysfunctions in patients with dementias involving degeneration of primarily frontal and frontal-subcortical brain areas. EF impairments are present in each of these types of dementing illnesses. Although EF impairments are present in AD, they are less prominent than the memory disorder in the neuropsychological profile of the disease and tend to become more pronounced later in the course of the illness. In contrast, patients with frontal or frontal-subcortical dementia may demonstrate executive dysfunction, which occurs earlier in the disease progression and may be initially more severe.

Discriminant cognitive factors in responder and non-responder patients with schizophrenia

To identify which improvements in cognitive function are associated with symptom resolution in schizophrenic patients treated with atypical antipsychotics.

DESIGN

a prospective open trial with atypical neuroleptics (risperidone, clozapine, quetiapine).

SETTING

Inpatient and outpatient units, Institute of Psychiatry.

PATIENTS

Thirty-nine patients with schizophrenia according to DSM-IV criteria were included. Clinical and cognitive assessment were done at baseline (T0) and again after six months of treatment (T2). Twenty-five patients completed the trial.

INTERVENTIONS

New-generation antipsychotics during six months. Patients were considered as responders if their PANSS score decreased at least 20% (n = 15) and non-responders if it did not (n = 10).

OUTCOME MEASURES

a computerized cognitive assessment comprised tests of short-term-memory (digit span), explicit long-term memory (word pair learning), divided attention, selective attention and verbal fluency (orthographic and semantic). Clinical assessment included PANSS and ESRS.

RESULTS

A discriminant function analysis was performed to determine which changes in cognitive performance predicted symptomatic response status. Semantic fluency and orthographic fluency were significant predictors. Together they correctly predicted responder status in 88% of cases. Memory was not a significant predictor of symptomatic response.

CONCLUSION

Verbal fluency discriminated the responder from the non-responder group during a pharmacological treatment.

Cerebral blood flow patterns underlying the differential impairment in category vs letter fluency in Alzheimer's disease

Verbal fluency tasks are used to assess language functioning in Alzheimer's disease (AD), and performance typically declines as the disease progresses. However, several studies have shown that Category Fluency performance (produce words from a category) declines faster than Letter Fluency performance (produce words beginning with a certain letter), which is not the case for other dementias. The purpose of this study was to determine if each of these two types of fluency tasks was associated with different patterns of cerebral blood flow abnormality in AD. A resting, Xenon-inhalation regional cerebral blood flow measurement (133Xe rCBF) and neuropsychological evaluation was administered to 25 patients with probable AD and 24 healthy elderly controls. Stepwise regression using rCBF measures as predictor variables was used to predict Category and Letter Fluency performance, in both a combined group of patients and controls, and in the patient group alone. Correlations were also computed between rCBF variables and the difference between normatively corrected scores on each task for each subject, which characterized the extent of the discrepancy between them. In full sample regressions, both Category and Letter Fluency were predicted by education and the decline in left inferior parietal flow, a focal AD-related deficit. Additional variance in Category fluency, however, was predicted by global mean flow, while additional variance in Letter Fluency was predicted by frontal flow. Within the patient sample, in turn, the primary predictor of Category Fluency was mean flow; the primary predictor of Letter Fluency was left-sided frontal flow. Analysis of the fluency difference score revealed that relatively greater impairment of Category Fluency was associated with more typical, AD-related deficits in posterior temporal and parietal perfusion. When the two were equivalently impaired, typical AD-related deficits were accompanied by marked deficits in frontal perfusion. These findings are consistent with the underlying neuropsychology of these tasks, and suggest that Category Fluency's stronger association to the most typical CBF deficits of AD account for its greater sensitivity to this disease. Letter Fluency deficits, on the other hand, carry significant information about the degree to which perfusion deficits have spread to frontal cortex.

Specific cognitive deficits in mild frontal variant frontotemporal dementia

Eight patients with relatively mild frontal variant frontotemporal dementia (fvFTD) were compared with age- and IQ-matched control volunteers on tests of executive and mnemonic function. Tests of pattern and spatial recognition memory, spatial span, spatial working memory, planning, visual discrimination learning/attentional set-shifting and decision-making were employed. Patients with fvFTD were found to have deficits in the visual discrimination learning paradigm specific to the reversal stages. Furthermore, in the decision-making paradigm, patients were found to show genuine risk-taking behaviour with increased deliberation times rather than merely impulsive behaviour. It was especially notable that these patients demonstrated virtually no deficits in other tests that have also been shown to be sensitive to frontal lobe dysfunction, such as the spatial working memory and planning tasks. These results are discussed in relation to the possible underlying neuropathology, the anatomical connectivity and the hypothesized heterogeneous functions of areas of the prefrontal cortex. In particular, given the nature of the cognitive deficits demonstrated by these patients, we postulate that, relatively early in the course of the disease, the ventromedial (or orbitofrontal) cortex is a major locus of dysfunction and that this may relate to the behavioural presentation of these patients clinically described in the individual case histories.

Executive dysfunction in Alzheimer's disease

Executive functioning was examined in 20 patients with Alzheimer's disease (AD) and 20 normal elderly subjects. The results showed that AD patients present lower performance compared to control subjects in all executive tasks, confirming that some executive deficits may be present in the first stages of the disease. A factorial analysis suggested that these deficits can be related to two domains of the executive functions: the inhibition abilities and the capacity to co-ordinate simultaneously storage and processing of information. Moreover, the performance on these factors is correlated to different anterior and posterior cortical areas.

Non-Alzheimer degenerative dementias

Recent progress in diagnostic criteria of non-Alzheimer degenerative dementias is reviewed. These dementias comprise frontotemporal dementias (including hereditary dementias), primary progressive aphasia and anarthria, corticobasal degeneration, progressive supranuclear palsy and dementia with Lewy bodies. The approach of studying these diseases has changed considerably with genetic and biochemical analyses. A molecular classification is suggested and the clinical significance of this classification is discussed.

Differential diagnosis of the major progressive dementias and depression in middle and late adulthood: a summary of the literature of the early 1990s

There is a preponderance of research on the neuropsychology of the various dementias. There are also direct comparisons between two or more dementias available in the literature. This paper sought to summarize the most recent literature, primarily from 1990 through mid-1996, including recent reviews of the literature from previous decades. The purpose was to provide, in one location, a summary of neuropsychological (i.e., cognitive, motor, and psychiatric) characteristics of major noninfectious, progressive dementias and depression of middle and late adulthood. It is hoped that this review, particularly a summary table provided, will serve as a guide in the differential diagnosis of the dementias by clinicians. In addition to Alzheimer's disease, vascular dementias, Parkinson's disease, Lewy body dementia, Huntington's disease, and frontal lobe dementia, the impact of depression on cognitive functioning is covered given the frequency with which neuropsychologists are asked to differentiate depression from primary dementia.

Compulsive behaviors as presenting symptoms of frontotemporal dementia

Frontotemporal dementia (FTD) is a common neurodegenerative dementia syndrome. Compulsive behaviors frequently occur in FTD and may be presenting symptoms of this disorder. This study evaluated compulsive behaviors as presenting symptoms in 29 patients with FTD compared to 48 patients with Alzheimer's disease (AD) enrolled in the UCLA Alzheimer's Disease Center. The FTD patients met the Lund and Manchester criteria for FTD and had predominant frontal hypoperfusion on single-photon emission computer tomography neuroimaging. The AD patients met National Institute of Neurological and Communicative Disorders-Alzheimer's Disease and Related Disorders criteria for clinically probable AD. Compulsive behaviors occurred in 11 FTD patients (38%) versus 5 AD patients (10%) (chi2 = 6.73, P < .01). This difference persisted after controlling for the younger age of the FTD group. There was a range of compulsive behaviors, with the most frequent being repetitive checking activities. Compulsive behaviors are common presenting symptoms among FTD patients and may result from an inability to inhibit urges to perform compulsive movements from damage to frontal-striatal circuits.

Loss of functional hemispheric asymmetry in Alzheimer's dementia assessed with near-infrared spectroscopy

In a total of 10 patients with dementia of the Alzheimer-type (DAT) and in 10 healthy controls near-infrared spectroscopy (NIRS), a new non-invasive optical method, was used to measure the changes of concentrations of oxy- (O2HB) and deoxyhemoglobin (HHB) in left and right hemispheric prefrontal brain tissue areas during performance of the Verbal Fluency Test (VFT). On a neuropsychological level, the healthy subjects performed better in the VFT than patients with DAT. Statistical analysis of the relative concentrations of O2HB and HHB measured with NIRS during performance of the VFT revealed a significant interaction of the hemispheric effects with the diagnosis. A possible interpretation of this finding is that a good performance in the VFT relies on a predominantly left hemispheric activation observed in controls, whereas a low number of correct responses is associated with a loss of this asymmetric activation in patients with DAT. Although both, patients and controls, performed better in the category version of the VFT, the metabolic effects of this task were significantly less pronounced than in the letter version. This indicates that different energy demands, according to the type of access to the memory stores, may be interpreted as the result of a less energy-demanding access to categorically stored information and adds further evidence to the view that memory departments in humans are organized according to categorical principles.

Frontal lobes pathology and dementia. An appraisal of the contribution of Leonardo Bianchi

This paper which was inspired by Leonardo Bianchi's work, published in English a hundred years ago, summarizes the main features of frontal dementias, with particular emphasis on Pick's Disease (PiD) and on Frontal Lobe Dementia (FLD). We intend to examine on one hand whether these behavioral changes follow pathology strictly limited to the frontal lobes and on the other hand whether these changes truly constitute a dementia. Currently available data suggest the following conclusions: 1) Lesions to the frontal lobes produce a dementia which is clearly different from the typical picture of Alzheimer's disease and which can be called a behavioral dementia. 2) The pathology of the so-called frontal dementias usually extends beyond the limits of the prefrontal cortex. 3) Executive functions classically thought to be related to frontal lobe structures are in fact associated with structures outside the frontal lobes, particularly in the telencephalic and limbic cortex. These findings in no way diminish the value of the work of Leonardo Bianchi. Rather, they strengthen it. We consider that the work of this great Neuroscientist remains highly relevant and that after 100 years, it still represents the starting basis for further works and ideas.

Frontotemporal dementia versus vascular dementia: differential features on mental status examination

OBJECTIVE

After Alzheimer's disease, vascular dementia (VaD) and frontotemporal dementia (FTD) are among the most common dementing illnesses. FTD may have a neuropsychological profile similar to that of VaD, and patients with these dementias may be difficult to distinguish on clinical examination. The purpose of this study was to elucidate distinct cognitive profiles of a large group of FTD and VaD patients on a brief, clinical mental status examination.

DESIGN

A comparison of 39 FTD patients and 39 VaD patients on a brief, clinical mental status examination.

SETTING

A Dementia Research Center and affiliated, university hospitals.

METHODS

The FTD patients were diagnosed by noncognitive clinical and neuroimaging criteria, and the VaD patients met NINDS-AIREN criteria for vascular dementia. The two dementia groups were comparable on three dementia assessment scales.

MEASUREMENTS

The mental status measures included the neuropsychological battery from the Consortium to Establish a Registry for Alzheimer's Disease (CERAD), plus supplementation from the Neurobehavioral Cognitive Status Examination (NCSE) for cognitive areas not assessed by the CERAD).

RESULTS

The FTD and VaD groups differed significantly on the mental status examination measures. FTD patients performed significantly better than the VaD patients on digit span and constructions, despite comparable performance by both groups on calculations. Although not statistically significant, the FTD group performed worse than the VaD group on verbal fluency and abstractions. These differences were not explained by group differences in age and education.

CONCLUSION

These results suggest that cognitive differences between FTD and VaD groups reflect greater frontal pathology in contrast to relative sparing of posterior cortex and subcortical white matter in FTD. These cognitive differences as measured by a mental status examination may help distinguish between these two dementia syndromes.

[Normative data on the verbal fluency test in the animal category in our milieu]

OBJECTIVE

Evaluate the performance on verbal fluency (VF) in our population in a Brazilian sample checking the influence of age and literacy.

METHODS

336 people without neurological or psychiatric complaints evaluated through Mini-Mental State Examination and VF (animals). For comparison, and to determine cut-off points, 65 people with cognitive loss followed at our clinic were also evaluated.

RESULTS

We found a mean of 13.8 animals in 1 minute, with the following distribution: illiterates, 11.9; up 4 years of education, 12.8; 4 to 7 years, 13.4; 8 years or more, 15.8 (p = 0.0001). In relation to age the means were: up to 64 years, 13.7; 65 years or more, 13.9. There was no difference between the two groups. The cut-off points were 9 for people under 8 years of education with a sensitivity of 75% for illiterates, 100% for low educational level (up 4 years), and 87% for middle level (4 to 7 years). The specificity was respectively 79%, 84%, and 88%. For the high educational level the mean was 13 with a sensitivity of 86% and specificity of 67%.

CONCLUSIONS

In the VF (animals) there is a significant influence of schooling and different cut-off points should be used.

Letter and category fluency in community-dwelling Canadian seniors: a comparison of normal participants to those with dementia of the Alzheimer or vascular type

Measures of letter (FAS) and category (Animal Naming) fluency were completed by community-dwelling, cognitively normal seniors (n = 635), and by individuals diagnosed with dementia of the Alzheimer type (DAT) (n = 155), or with vascular dementia (n = 39). Among normal seniors, category, but not letter fluency, declined with age, females performed better than males on letter but not on category fluency, and performance increased with education on both tasks. Among participants with DAT, letter fluency was influenced by level of education, whereas category fluency was education-, age-, and gender-invariant. Both measures differentiated normal seniors from those with dementia. Category fluency was more impaired than letter fluency at both mild and moderate stages of dementia, but neither task differentiated DAT from vascular dementia.

Word-list generation deficits in dementia

To evaluate the specificity of the semantic fluency deficit in Alzheimer's disease (AD), we compared the performances of patients with AD, Huntington's disease (HD), vascular dementia (VD), and healthy control subjects on tasks of category (i.e., semantic) and first-letter (i.e., phonemic/lexical) word list generation. As compared to age-appropriate controls, all three patient groups demonstrated relatively more impaired semantic than phonemic fluency. Dementia severity did not affect this relationship. Thus, the greater vulnerability of semantically guided fluency is not specific to AD but occurs in other dementias as well. Deficits in both the organization of semantic memory and retrieval from long-term storage appear to contribute to the relatively poorer performance on semantic than phonemic fluency tasks observed in patients with AD, VD, and HD.

Performance on neuropsychological tests related to single photon emission computerised tomography findings in frontotemporal dementia

BACKGROUND

This study examines relations between regional cerebral blood flow (rCBF) and neuropsychological test results, age at onset and duration of disease in patients with frontotemporal-type dementia (FTD).

METHOD

Sixteen patients with a diagnosis of probable FTD were examined using single photon emission computerised tomography (SPECT) with 99mTc-HMPAO as the tracer. The rCBF of 14 regions of interest relative to cerebellar blood flow was calculated. Psychological tests assessing language, verbal fluency, memory and visuospatial constructive ability were given.

RESULTS

Correlations were demonstrated between a global impairment score and relative blood flow in lateral frontal, medial frontal and left orbital frontal areas. Verbal fluency scores correlated with left lateral frontal, medial frontal and left anterior inferior temporal blood flow. No relationships between decrease in CBF and age at onset or duration of disease, or between impaired cognitive function and age at onset or duration of disease were found.

CONCLUSIONS

The present study demonstrates a close coupling between reduced rCBF and specific neuropsychological deficits in FTD.

Generation effect in short-term verbal and visuospatial memory: comparisons between dementia of Alzheimer type and dementia of frontal lobe type

Memory deficit is the predominant presenting symptom in dementia. To compare short-term memory (STM) deficit in early dementia of Alzheimer type (DAT) vs frontal lobe type (DFT), and determine the residual memory capacity for stimulation, the generation effect (the memory advantage of items generated rather than read) was tested on verbal and visuospatial STM in patients with DAT (n = 10), DFT (n = 9) and in age-matched normal controls (n = 12). The generation effect enhanced performance in all groups. However, the profile of STM deficit differed in the two dementias: verbal and visuospatial memory were both decreased in DAT vs verbal memory only in DFT. These results provide a further criterion for differentiating between DAT and DFT, and show that memory performance can be enhanced in early dementia using techniques such as the generation effect.