The Philadelphia Brief Assessment of Cognition (PBAC): A Validated Screening Measure for Dementia

The Philadelphia Brief Assessment of the Cognition (PBAC) is a brief dementia-screening instrument. The PBAC assesses five cognitive domains: working memory/executive control; lexical retrieval/language; visuospatial/visuoconstructional operations; verbal/visual episodic memory; and behavior/social comportment. A revised version of the PBAC was administered to 198 participants including patients with Alzheimer's disease (AD) (n?=?46) and four groups of patients with frontotemporal dementia (FTD) syndromes: behavioral-variant FTD (bvFTD; n?=?65), semantic-variant primary progressive aphasia (PPA) (svPPA; n?=?22), non-fluent/agrammatic-variant PPA (nfaPPA; n?=?23), and corticobasal syndrome (CBS; n?=?42), and a group of normal controls (n?=?15). The total PBAC score was highly correlated with the MMSE. The criterion validity of the PBAC was assessed relative to standard neuropsychological test performance. Using standard neuropsychological test performance as a criterion, the total PBAC score accurately identified the presence and severity of dementia. Intra-class correlations between PBAC subscales and standard neuropsychological tests were highly significant. PBAC subscales demonstrated good clinical utility in distinguishing AD and FTD subtypes using receiver operating characteristic analysis and standard diagnostic performance statistics to determine optimal subscale cut scores. The PBAC is a valid tool and able to assesses differential patterns neuropsychological/behavioral impairment in a broad range of neurodegenerative conditions.     

Preservation of reasoning in primary progressive aphasia: further differentiation from Alzheimer's disease and the behavioral presentation of frontotemporal dementia

Primary Progressive Aphasia (PPA) is a clinical dementia syndrome characterized by the gradual dissolution of language without impairment of other cognitive domains for at least the first 2 years of illness (M.-M. Mesulam, 1982, 2001). It is difficult to demonstrate the integrity of nonlanguage domains in PPA because most neuropsychological tests of memory, reasoning, and attention require language competence for their performance. In the present study, reasoning and cognitive flexibility were tested nonverbally in patients with PPA using a modified ten-item version of the Visual Verbal Test (Feldman & Drasgow, 1959). This test measures the ability to detect similarities among objects and to sort a single set of objects according to two different principles. The performance of PPA patients (n = 20) was compared with that of patients with dementia of the Alzheimer type (AD) (n = 20), patients with the comportmental/executive dysfunction variant of frontotemporal dementia (FTD) (n = 16), and cognitively intact controls (n = 20). Patients with PPA and controls performed similarly, detecting commonalities among objects and shifting from one sorting principle to another. In contrast, both AD and FTD subjects were significantly impaired on both measures. These results provide evidence of preserved reasoning in PPA, further differentiating this syndrome from other behaviorally focal dementia syndromes.     

Rate of cognitive change measured by neuropsychologic test performance in 3 distinct dementia syndromes

Progressive decline in cognition is a hallmark feature of dementia, and the rate and profile of cognitive decline has been well characterized in Alzheimer disease (AD). Less is known about decline in cognition over time in other forms of dementia such as the behavioral variant of frontotemporal dementia (FTD) and primary progressive aphasia (PPA). The present study examined rate of cognitive decline across domains of memory, language, and executive function measured by neuropsychologic tests, in AD (n=84), FTD (n=66), and PPA (n=44). Patients were in the mild stages of dementia, with comparable duration of illness at the baseline evaluation. A best linear unbiased predictor (BLUP) analysis was used in which the slope of the relationship between a cognitive measure and time was estimated for each person. AD subjects demonstrated a floor effect on measures of memory at baseline and a decline on measures of language and executive functioning over time. FTD showed the greatest decline over time on the Mini-Mental State Examination, executive functioning, and naming. PPA patients demonstrated prominent decline on language measures, verbal memory measures, and attention. Results suggest that the profile of rate of change over time has unique features on the basis of the type of dementia syndrome. However, there is overlap in the profiles of decline likely influenced by the overlap in cognitive constructs measured by neuropsychologic tests. The comparison of the rate of decline in FTD and PPA may also reflect the neuroanatomic overlap in these syndromes over time.     

Profiles of decline in activities of daily living in non-Alzheimer dementia

Assessment of functional ability is an essential component in the clinical diagnosis of dementia. Most studies have primarily focused on disability due to Alzheimer disease (AD), and less is known about profiles of functional impairment in other dementia syndromes. Functional ability was assessed in individuals in the early stages of AD (N=100), the behavioral variant of frontotemporal dementia (FTD) (N=57), and primary progressive aphasia (PPA) (N=61), using the activities of daily living questionnaire (Johnson et al, 2004). The average duration of illness for the 3 groups ranged from 3.4 to 3.9 years. Overall level of functional impairment and the profile of abilities across subscales of Self-Care, Household Care, Employment and Recreation, Shopping and Money, Travel, and Communication were examined. Results showed that overall functional ability was moderately impaired in AD and FTD, and mildly impaired in PPA. For all groups, more complex ADLs were impaired early on, with relative preservation of self-care activities. The Communication score was the least impaired next to Self-Care for FTD and AD, and the most impaired for PPA patients. The activities of daily living questionnaire may capture aspects of preserved functioning that are not apparent from patients' scores on cognitive tests, especially for those with aphasia.     

A brief cognitive test battery to differentiate Alzheimer's disease and frontotemporal dementia

OBJECTIVES: To validate a simple bedside test battery designed to detect mild dementia and differentiate AD from frontotemporal dementia (FTD). METHODS: Addenbrooke's Cognitive Examination (ACE) is a 100-point test battery that assesses six cognitive domains. Of 210 new patients attending a memory clinic, 139 fulfilled inclusion criteria and comprised dementia (n = 115) and nondementia (n = 24) groups. The composite and the component scores on the ACE for the two groups were compared with those of 127 age- and education-matched controls. Norms and the probability of diagnosing dementia at different prevalence rates were calculated. To evaluate the ACE's ability to differentiate early AD from FTD, scores of the cases diagnosed with dementia with a Clinical Dementia Rating < or = 1 (AD = 56, FTD = 24, others = 20) were compared. RESULTS: Two cut-off values for the ACE composite score (88 and 83) were of optimal utility depending on the target population. The ACE had high reliability, construct validity, and sensitivity (93%, using 88 as cut-off). Using the lower cut-off of 83, the ACE had a higher sensitivity (82%) and predictive value than the Mini-Mental State Examination for a wide range of dementia prevalence. The ACE differentiated AD from FTD, and the VLOM ratio (derived using component scores: [verbal fluency + language]/[orientation + memory]) of <2.2 for FTD and >3.2 for AD was highly discriminating. CONCLUSION: The ACE is a brief and reliable bedside instrument for early detection of dementia, and offers a simple objective index to differentiate AD and FTD in mildly demented patients.     

Neuropsychological and functional measures of severity in Alzheimer disease, frontotemporal dementia, and semantic dementia

Many studies attempting to compare the clinical features in different dementia syndromes have attempted to control for overall disease severity using neuropsychological or functional measures. However, these measures may not give equivalent estimates of disease severity. We examined a functional measure of severity (Clinical Dementia Rating scale [CDR] scores) in patients with Alzheimer disease (AD, n = 23), frontotemporal dementia (FTD, n = 24), and semantic dementia (SD, n = 25) who were matched for age and Mini-Mental State Examination (a neuropsychological measure of severity). Total CDR scores were significantly worse in the FTD group compared with both AD and SD patients, whose total CDR scores were similar to each other. FTD showed no difference in memory or orientation compared with AD but did show more impairment in judgment and problem solving, community affairs, home and hobbies, and personal care compared with AD and SD. Thus, in FTD the CDR reveals functional impairments in a wide variety of domains that are more severe than those seen in AD or SD patients with an equivalent Mini-Mental State Examination.     

Primary progressive aphasia and Pick complex

Ten autopsied patients from a prospectively followed, clinically defined, neuropsychologically and radiologically documented cohort with primary progressive aphasia were histologically characterized. All were variants of frontotemporal degeneration (Pick complex): Pick body dementia, n=3, corticobasals degeneration (CBD), n=4, and tau and synuclein negative ubiquitinated inclusions of the motor neuron disease type, n=3. All shared superficial cortical spongiosis, neuronal loss, and gliosis. Although most patients had fluent anomic aphasia at onset, all progressed to a nonfluent or mute state. Comprehension, episodic memory, and activities of daily living were initially preserved. Three cases with Pick body dementia had verbal apraxia and stuttering at onset. Two of the patients with CBD pathology were older than the average primary progressive aphasia (PPA). All patients developed secondary syndromes either of frontotemporal dementia (FTD) and/or extrapyramidal-apraxic manifestations (CBD). By the time autopsy was obtained, the pathology appeared outside the language areas. Progressive aphasias secondary to Alzheimer's disease (AD) were excluded on the basis of early loss of memory and comprehension.Rather than the previously emphasized histological heterogeneity, clinically probable PPA has a predictive value of a group of related pathologies, collectively named frontotemporal degeneration, or Pick complex. This series of autopsied cases provides evidence for the clinical and pathological overlap of PPA with FTD and CBD, and contributes to the diagnostic and neuropsychological definition of PPA.     

Differentiating frontal and temporal variant frontotemporal dementia from Alzheimer's disease

OBJECTIVE/BACKGROUND: To determine whether difficulty in the early differentiation between frontotemporal dementia (FTD) and AD may arise from a failure to discriminate between the temporal and frontal variants of FTD. METHODS: Neuropsychological profiles of patients with early dementia of Alzheimer type (DAT; n = 10), the temporal variant of FTD (tv-FTD or semantic dementia; n = 5), and the frontal variant of FTD (fv-FTD; n = 10) were compared to each other and normal controls (n = 10). Structural MRI demonstrated temporal lobe atrophy in the tv-FTD patients and frontal lobe atrophy in the fv-FTD group. RESULTS: Subjects with tv-FTD showed severe deficits in semantic memory with preservation of attention and executive function. Subjects with fv-FTD showed the reverse pattern. Attention and executive function impairment separated the fv-FTD patients from the early DAT subjects, who were densely amnesic. CONCLUSION: The double dissociation in performance on semantic memory and attention/executive function clearly separated the temporal and frontal variants of FTD and aids the early differentiation of FTD from AD. The characteristic cognitive profiles reflect the distribution of pathology within each syndrome and support the putative role of the inferolateral temporal neocortex in semantic memory, the medial temporal lobe structures of the hippocampal complex in episodic memory, and the frontal lobes in executive function.     

Philadelphia Brief Assessment of Cognition in healthy and clinical Brazilian sample

The Philadelphia Brief Assessment of Cognition (PBAC) is a neuropsychological screening instrument that assesses five cognitive domains: working memory, visuospatial functioning, language, episodic memory and comportment. The aim is to verify if PBAC can properly be used in the Brazilian sample. Participated in this study: (a) 200 healthy volunteers - 100 young [21.6(2.5) years old] and 100 older adults [70.1(7.3) years old]; >12 years of education; (b) 30 Alzheimer's patients (AD) [73.7(5.7) years old], 4-11 years in education. The PBAC scores: (a) 95.8(2.6), 90.0(4.4) and (b) 65.0(10.8) were correlated with the Mini-Mental State Examination (MMSE) for young 29.1(0.9), older adults 28.3(1.4) and AD 18.4(3.0) groups. A positive correlation between MMSE and PBAC (r=0.9, p<0.001) was found. Negative correlations were observed between PBAC domains [memory (-0.63), visuospatial abilities (-0.44) and working memory (-0.3) tasks]. MANOVA showed a better male performance in visuospatial functioning (F=8.5, p=0.004). The Brazilian version of PBAC proved to be a promising screening instrument for clinical purposes.     

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.     

CAN FRONTOTEMPORAL DEMENTIA AND ALZHEIMER'S DISEASE BE DIFFERENTIATED USING A BRIEF BATTERY OF TESTS?

Objective. To compare the performance of patients with frontotemporal dementia (FTD) and Alzheimer's disease (AD) on a range of simple neuropsychological tests. Design. A battery of neuropsychological tests easily applied at the bedside, consisting of traditional tests of memory, attention and executive function, were given together with tests of motor sequencing and examination of frontal release signs. In addition, we devised a theoretically motivated test of dual attention—a story with distraction which also contained a ‘social dilemma’. Setting. Specialist memory and cognitive disorders clinic. Patients. 12 patients with FTD and 12 patients with AD, matched for overall level of dementia on the Mini-Mental State Examination, were selected. Results. In general, the difference in results between FTD and AD patients was small. However, a composite score derived from the presence of a grasp and pout reflex, the number of perseverations during category fluency for animals and response to the social dilemma within the two stories produced a sensitivity of 83.3% and specificity of 91.6%. There was also a highly significant difference between patients with FTD and AD in scores achieved on the Clinical Dementia Rating Scale reflecting the marked change in behaviour that patients with FTD suffer, even at a stage when memory functions are well preserved. Conclusion. Traditional neuropsychological tests were poor at differentiating cases of FTD and AD; however, a composite (SIFTD) score appears potentially useful but requires prospective validation. Better methods of assessing the changes in comportment that characterize the early stages of FTD are required. © 1997 by John Wiley & Sons, Ltd.     

Neuropsychological performance of right- and left-frontotemporal dementia compared to Alzheimer's disease.

The performance of 16 patients with Alzheimer's disease (AD) was compared to 11 patients with right-frontotemporal dementia (FTD) and 11 patients with left-FTD on a comprehensive neuropsychological battery. Standardized scores (i.e., z scores based on normal control data) were analyzed for 5 cognitive domains. The results revealed that the AD group displayed significant impairment in visual-constructional ability relative to the two FTD groups; however, no significant difference was found between the groups on memory scores (verbal and nonverbal). Patients with left-FTD scored significantly below patients with AD on the language measures (e.g., word retrieval, verbal semantic memory), and verbal executive ability (phonemic fluency); AD patients did not differ from patients with right-FTD on these measures. Patients with right-FTD exhibited significantly more perseverative behavior than AD patients; AD patients did not differ from left-FTD patients on this parameter. These results indicate that the pattern of neuropsychological performance of AD patients is distinguishable from patients with left and right frontal frontotemporal dementia.     

The Middelheim Frontality Score: a behavioural assessment scale that discriminates frontotemporal dementia from Alzheimer's disease

BACKGROUND: Despite striking neuropsychological and behavioural differences between Alzheimer's disease (AD) and frontotemporal dementia (FTD), clinical diagnostic criteria failed to discriminate FTD from AD patients. We therefore developed the Middelheim Frontality Score (MFS), a disease-long clinical and behavioural assessment tool that measures frontal lobe features, and set up this prospective study in clinically diagnosed AD and FTD patients to assess discriminatory power and intra- and inter-rater variability. METHODS: Patients with probable AD (n = 400) and FTD (n = 62) were included. The MFS was obtained by summating the scores obtained in a standardized fashion on ten items yielding a total maximal score of 10. Information was obtained through an interview of the patient and her/his caregiver, clinical files and behavioural observation. RESULTS: Comparing mean total MFS scores, FTD patients (6.3 +/- 1.8) had significantly higher scores than AD patients (3.1 +/- 1.8) (p < 0.001). Distribution of scores on individual MFS items was significantly different between both disease groups (chi(2) = 76.2; p < 0.001). A moderately positive and highly significant correlation was shown between the total MFS score and diagnosis FTD (r = 0.478; p < 0.0001). Applying a total MFS score of 5 as discriminatory cut-off, a specificity of 89.0% and a sensitivity of 88.7% were achieved. Intra- and inter-rater variability was calculated in a different study population by means of retest correlation, revealing moderate to strong positive correlations of high statistical significance. CONCLUSIONS: The MFS is a clinical and behavioural assessment scale that measures frontal lobe features and that was shown to reliably discriminate FTD from AD patients.     

Evaluation of the NINCDS-ADRDA criteria in the differentiation of Alzheimer's disease and frontotemporal dementia

OBJECTIVES: The diagnosis of Alzheimer's disease (AD) is now reliant on the use of NINCDS-ADRDA criteria. Other diseases causing dementia are being increasingly recognised--for example, frontotemporal dementia (FTD). Historically, these disorders have not been clearly demarcated from AD. This study assesses the capability of the NINCDS-ADRDA criteria to accurately distinguish AD from FTD in a series of pathologically proved cases. METHODS: The case records of 56 patients (30 with AD, 26 with FTD) who had undergone neuropsychological evaluation, brain imaging, and ultimately postmortem, were assessed in terms of whether at initial diagnosis the NINCDS-ADRDA criteria were successful in diagnosing those patients who had AD and excluding those who did not. RESULTS: (1) The overall sensitivity of the NINCDS-ADRDA criteria in diagnosing "probable" AD from 56 patients with cortical dementia (AD and FTD) was 0.93. However, the specificity was only 0.23; most patients with FTD also fulfilled NINCDS-ADRDA criteria for AD. (2) Cognitive deficits in the realms of orientation and praxis significantly increased the odds of a patient having AD compared with FTD, whereas deficits in problem solving significantly decreased the odds. Neuropsychological impairments in the domains of attention, language, perception, and memory as defined in the NINCDS-ADRDA statement did not contribute to the clinical differentiation of AD and FTD. CONCLUSION: NINCDS-ADRDA criteria fail accurately to differentiate AD from FTD. Suggestions to improve the diagnostic specificity of the current criteria are made.     

Alzheimer's disease and frontal variant of frontotemporal dementia

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.     

Neural correlates of episodic memory in behavioral variant frontotemporal dementia

Impaired episodic memory is currently an exclusion criterion for behavioral variant frontotemporal dementia (bv-FTD), although prior studies have shown that neuropsychological memory performance varies from very impaired to intact in such patients. Our study investigated i) whether this variability might be due to the admixture of true bv-FTD and phenocopy syndrome patients and ii) the neural correlates of episodic memory deficits in bvFTD. Groups of patients with true bvFTD (n = 14), phenocopy syndrome (n = 6), Alzheimer's disease (AD) (n = 14), and healthy controls (n = 15) underwent memory testing and had MRI scanning with ratings of regional brain atrophy. Phenocopy patients did not differ to controls on memory scores or atrophy ratings. By contrast, bvFTD and AD patients were impaired on both measures in comparison to controls and more importantly, bvFTD and AD did not differ on memory scores. Atrophy patterns differed, with AD showing typical medial temporal lobe atrophy, while bvFTD patients had predominantly prefrontal cortex atrophy. In bvFTD neuropsychological memory performance correlated with frontal atrophy ratings while in AD significant correlations were found between memory and both medial temporal lobe and frontal atrophy ratings. Taken together, out data shows that bvFTD patients can show a similar degree of episodic memory impairment on neuropsychological tests to AD patients, however, the neural correlates differ. The previously variable reported memory performance in bvFTD is likely due to the inclusion of phenocopy patients, who are mostly undistinguishable from controls. These findings have implications for the diagnosis of bvFTD.     

Is the Addenbrooke’s Cognitive Examination effective to detect frontotemporal dementia?

We evaluated the Addenbrooke's cognitive examination (ACE), a simple instrument to differentiate frontotemporal dementia (FTD) from Alzheimer's disease (AD), in our dementia patients clinic population. The Verbal-Language/Orientation-Memory (VLOM) ratio, which compares its language and memory scores, determines whether FTD or AD is more likely. The ACE was translated into French with adaptation maintaining the number of words in the name and address learning and delayed recall test, and with cultural adaptation for the semantic memory. The 85 included subjects had no evidence of two or more organic pathologies, after at least six months of follow-up, and an MMSE score>or=20/30. Patients with cognitive impairment due to alcohol intake were excluded. The diagnosis of a specific dementing illness was based on the consensus of the neurologist and neuropsychologists in the team. Thereafter, another neurologist expert in dementia, blinded to the ACE result and to the diagnosis and treatment, reviewed all cases files and proposed a diagnosis. A diagnostic agreement was reached for 79 cases (92.9%) with 40 (50.6%) dementia: 25 AD (62.5 %), 9 FTD (22.5 %).We estimated that the sensitivity for detecting dementia of an ACE score3.2 was 72%,with a specificity of 69.4%. We conclude that, when used as originally proposed, ACE is very accurate for the detection of dementia, but much less effective in discriminating the most common frontal variant of FTD.     

Comparison of polysomnographic variables and their relationship to cognitive impairment in patients with Alzheimer's disease and frontotemporal dementia

Polysomnograhic (PSG) studies in Alzheimer’s disease (AD) show REM sleep abnormalities, which may be indicative for the deterioration of cholinergic pathways and probably closely linked to declarative memory impairment. To clarify the specificity of the association between sleep and cognitive impairment in dementia, we compared AD patients with patients suffering from frontotemporal dementia (FTD) with regard to PSG and neuropsychological variables. 15 AD and 6 FTD patients underwent polysomonography and a neuropsychological battery (CERAD-NB). Group differences (age: AD > FTD; education level: AD < FTD) were considered as covariates. Polysomnography revealed a trend towards increased REM latency and reduced REM sleep in AD, as well as a decrease of stage 2 sleep, however, at least partly due to effects of age. Declarative memory was more impaired in AD than in FTD, but this difference disappeared when adjusted for covariates. While no relationship was found between REM sleep and CERAD-NB parameters, strong positive correlations between stage 2 sleep and declarative memory measures were observed, which were also detectable when analyzing both groups separately. Based on these results we conclude that REM sleep alterations may be specific for AD, distinguishable from other dementia diagnoses, whereas NonREM stage 2 sleep may be related to declarative memory formation in dementia independent of subtype.     

The differentiation of mild frontotemporal dementia from Alzheimer's disease and healthy aging by neuropsychological tests

BACKGROUND: Frontotemporal dementia (FTD) is difficult to diagnose in the early stages and may be misdiagnosed as Alzheimer's disease (AD) or as a psychiatric disorder. This study aimed to investigate neuropsychological function in FTD of mild severity and compare it to that of mild AD and healthy control participants. METHODS: The study comprised 11 individuals with FTD, 29 with AD and 27 healthy controls. Participants completed a comprehensive neuropsychological assessment in which each area of cognitive function was examined with several widely used clinical tests. Test scores were converted to age-corrected scaled scores and combined to form indices for six areas of cognitive function. These indices were attention, psychomotor speed, memory acquisition, memory recall, executive function and constructional ability. RESULTS: The FTD group performed below the level of the controls in all areas except constructional ability. FTD and AD groups showed distinct patterns of neuropsychological performance. The FTD group showed predominantly executive dysfunction with less impaired memory function, while the AD group showed the opposite pattern. The capacity of the tests to discriminate between groups was good overall, with 90% of the total sample correctly classified. Predictive success for the FTD group was 64%, given a base rate of 16%. CONCLUSION: Administration of a comprehensive neuropsychological protocol including several tests of executive function allows increased certainty about accurate clinical diagnosis of mild FTD.     

Neuropsychological deficits associated with Alzheimer's disease in the very-old: discrepancies in raw vs. standardized scores.

The profiles of neuropsychological deficits associated with Alzheimer's disease (AD) in Young-Old (M age and 70) and Very-Old (M age > 80) patients were compared, along with possible modifying effects of apolipoprotein E (APOE) genotype on these profiles. A comprehensive battery of neuropsychological tests was administered to the two AD patient groups (Young-Old: n = 33; Very-Old: n = 48) and their respective age-matched normal control (NC) groups who remained free of dementia on follow-up examinations over a 1 to 10 year period (Young-Old: n = 43; Very-Old: n = 36). AD and NC groups did not differ in education levels or gender distributions. Young-Old AD and Very-Old AD groups were comparable in education, gender, dementia severity, and disease duration. Results showed that both AD groups achieved comparable raw scores on all the neuropsychological measures. However, when scores were standardized on the basis of performance of their respective NC groups (i.e., age-corrected z scores), Very-Old AD patients significantly outperformed Young-Old AD patients on tests of executive functions, visuospatial skills, and delayed memory. Furthermore, the relationship between age and memory and executive function deficits in AD was modified by APOE genotype. These data suggest that the profile of neuropsychological deficits associated with AD in the Very-Old lacks the disproportionate saliency of episodic memory and executive function deficits typical of the Young-Old.