Functional Ability in Executive Variant Alzheimer's Disease and Typical Alzheimer's Disease

A frontal, or executive, variant of Alzheimer's disease (EAD) has been described in the literature in which frontal dysfunction accompanies temporal and parietal changes in the early stages of the illness. However, no study has empirically investigated associated aspects, such as neuropsychiatric symptoms, instrumental activities of daily living, or caregiver burden in this EAD subgroup. We compared the performance of two subgroups of mild Alzheimer's disease patients (e.g., EAD and typical Alzheimer's disease; TAD) on neuropsychological and associated measures. Results revealed that the EAD group, selected based on poor executive scores, did not significantly differ from the TAD group on nonexecutive neuropsychological tests of intelligence, language, verbal and nonverbal memory, or visual-spatial abilities. However, the EAD group evidenced more severe neuropsychiatric symptoms, impaired activities of daily living, and greater caregiver distress than the TAD group. Thus, the EAD subgroup is characterized by executive dysfunction, neuropsychiatric symptoms, and functional disability in excess of that seen in TAD. Whether our EAD subgroup represents an actual frontal variant of Alzheimer's disease awaits replication in a larger sample including neuroimaging and pathological confirmation, as well as longitudinal assessment of cognition and neuropsychiatric symptoms.     

Impaired insight in Alzheimer's disease.

We studied insight into illness in 41 patients with probable Alzheimer's disease. An impaired insight score was developed by measuring discrepancies between patient report and caregiver report on standard instruments of activities of daily living. Insight was more impaired in subjects with greater dementia severity and subjects with paranoid delusions. In a multivariate analysis, the best neuropsychological predictors of impaired insight were the Continuous Performance Test and the Visual Reproduction Test. We speculate that the impaired insight of Alzheimer's disease has two components: confabulation reflecting prefrontal dysfunction and anosognosia reflecting right-hemisphere dysfunction.     

Apathy and executive function in Alzheimer's disease.

Apathy is a common behavioral disturbance in patients with Alzheimer's disease (AD). Recent studies have linked the presence of apathy to alterations in frontal lobe functions, but few studies have explored the relationship using standard neuropsychological measures in patients with AD. We administered a comprehensive battery of neuropsychological tests and a behavior rating scale to 80 patients with AD. We explored the relationship of apathy to executive dysfunction. AD patients with apathy performed significantly worse on tests of executive function (WAIS-R Digit Symbol, Trail-Making, Stroop Color Interference Test) than AD patients without apathy. The presence of dysphoria did not modify these results and no significant relationships were found between tests of executive functions and dysphoria. Performance on executive measures as a group were effective in correctly classifying patients as apathetic or nonapathetic with 75% accuracy. Neuropsychological measures not dependent on executive functions were unrelated to apathy. Apathy is associated with executive dysfunction and not with other neuropsychological deficits. Apathy is distinct from dysphoria.     

Neurobehaviors and psychotic symptoms in Alzheimer's disease.

Psychotic symptoms are common in Alzheimer's disease (AD) and clinicoanatomical and neuropsychological evidence indicate an association between these symptoms and frontal lobe dysfunction. Neuro-behaviors associated with frontal dysfunction were assessed in Alzheimer's disease (AD) patients with (n = 20) and without psychotic symptoms (n = 21) matched for mean age, education, gender, and dementia severity. The Frontal Lobe Personality Scale (FLOPs) was completed by patient caregivers to measure behaviors typically associated with frontal dysfunction. Findings indicated that AD patients with psychotic symptoms exhibited significantly greater neurobehavioral dysfunction (FLOPs M = 130.69, SD = 24.70) than AD patients without psychotic symptoms (FLOPs M = 111.10, SD = 25.83). Subscale analyses indicated that psychotic AD patients were more dis-inhibited (M = 28.28, SD = 7.54) than patients without psychotic symptoms (M = 20.92, SD = 4.9). Findings are consistent with and contribute to previous neuropsychological and clinicoanatomical research suggesting increased frontal dysfunction in AD with psychotic symptoms and lend additional empirical support to subtyping AD based on the presence of psychotic symptoms. Furthermore, findings provide preliminary evidence indicating which specific type of neurobehavioral abnormalities are related to the presence of distressing psychotic symptoms.     

Executive dysfunction in Alzheimer disease

BACKGROUND: Executive dysfunction (EDF) is common in Alzheimer disease (AD); however, its relationship to other symptoms is difficult to assess in patients with AD. OBJECTIVES: To determine the prevalence of EDF and study its relationship to cognitive, functional, and neuropsychiatric symptoms in patients with AD. DESIGN, SETTING, AND PATIENTS: A retrospective analysis of data from participants in the English Instruments Protocol of the Alzheimer's Disease Cooperative Study. Subjects were drawn from a sample of patients evaluated at tertiary referral centers. RESULTS: A total of 64% of AD patients were classified as having EDF. Patients with EDF performed worse on tests of cognition (P <.001), dementia severity (P <.001), and activities of daily living (P =.01) and had more frequent symptoms of psychosis (P =.03) with greater emergence during the 12-month interval (P =.03) compared with patients with normal executive function. Less than 30% of the variance in executive function performance was explained by cognitive measures. CONCLUSION: These findings support the assessment of executive function in persons with AD and the importance of frontal lobe dysfunction in AD.     

Qualitative neuropsychological performance characteristics in frontotemporal dementia and Alzheimer's disease

BACKGROUND: Frontotemporal dementia (FTD) and Alzheimer's disease are clinically distinct disorders, yet neuropsychological studies have had variable success in distinguishing them. A possible reason is that studies typically rely on overall accuracy scores, which may obscure differences in reasons for failure. OBJECTIVES: To explore the hypothesis that analysis of qualitative performance characteristics and error types, in addition to overall numerical scores, would enhance the neuropsychological distinction between FTD and Alzheimer's disease. METHODS: 38 patients with FTD and 73 with Alzheimer's disease underwent assessment of language, visuospatial abilities, memory, and executive function, using a neuropsychological screening instrument and standard neuropsychological tests. In each of these cognitive domains, performance characteristics and error types were documented, in addition to numerical scores on tests. RESULTS: Whereas comparison of neuropsychological test scores revealed some group differences, these did not occur consistently across tests within cognitive domains. However, analysis of performance characteristics and error types revealed qualitative differences between the two groups. In particular, FTD patients displayed features associated with frontal lobe dysfunction, such as concrete thought, perseveration, confabulation, and poor organisation, which disrupted performance across the range of neuropsychological tests. CONCLUSIONS: Numerical scores on neuropsychological tests alone are of limited value in differentiating FTD and Alzheimer's disease, but performance characteristics and error types enhance the distinction between the two disorders. FTD is associated with a profound behavioural syndrome that affects performance on cognitive assessment, obscuring group differences. Qualitative information should be included in neuropsychological research and clinical assessments.     

Neuropsychological predictors of everyday memory and everyday functioning in patients with mild Alzheimer's disease

The contributions of executive function, naming, visuoperception, and delayed recall to everyday memory abilities and everyday living activities were examined in a sample (n = 24) of mildly impaired Alzheimer's disease (AD) patients. Everyday memory was rated independently by the patient and by a caregiver, and everyday functioning was rated by a caregiver. For patient-rated everyday memory, verbal recall accounted for 23% of the variance, while naming performance alone accounted for 56% of the variance in caregiver-rated everyday memory. Executive function was a unique and significant predictor of caregiver-rated functional daily living skills, accounting for 40% of the variance. Clinician's ratings of patient unawareness of deficit correlated with the discrepancy between caregiver and patient rating of memory. Caregiver reports of memory impairment appear to be influenced by naming abilities, indicating that language dysfunction may be misinterpreted as reflecting memory impairment. Helping caregivers distinguish between these two abilities may result in more accurate reporting of patients' impairments.     

Cerebral correlates of psychotic symptoms in Alzheimer's disease

BACKGROUND: Psychotic symptoms are produced by distributed neuronal dysfunction. Abnormalities of reality testing and false inference implicate frontal lobe abnormalities. OBJECTIVES: To identify the functional imaging profile of patients with Alzheimer's disease manifesting psychotic symptoms as measured by single photon emission computed tomography (SPECT). METHODS: Twenty patients with Alzheimer's disease who had SPECT and clinical evaluations were divided into two equal groups with similar mini mental status examination (MMSE), age, sex, and the range of behaviours documented by the neuropsychiatric inventory (NPI), except delusions and hallucinations. SPECT studies, registered to a probabilistic anatomical atlas, were normalised across the combined group mean intensity level, and subjected to a voxel by voxel subtraction of the non-psychotic minus psychotic groups. Subvolume thresholding (SVT) corrected random lobar noise to produce a three dimensional functional significance map. RESULTS: The significance map showed lower regional perfusion in the right and left dorsolateral frontal, left anterior cingulate, and left ventral striatal regions along with the left pulvinar and dorsolateral parietal cortex, in the psychotic versus non-psychotic group. CONCLUSION: Patients with Alzheimer's disease who manifest psychosis may have disproportionate dysfunction of frontal lobes and related subcortical and parietal structures.     

额叶变异型阿尔茨海默病的临床和影像学特征一例

目的额叶变异型阿尔茨海默病(AD)是一种以精神行为等症状为主要表型的少见特殊类型AD,本文报道1例额叶变异型AD的临床特点、影像学特征,以增加临床医生对该病的认识。方法报道1例额叶变异型AD患者的临床资料,分析其临床表现、辅助检查及影像学资料。结果本例患者以妄想和行为异常等为主要和最早临床表现,发病2年后才出现记忆力减退、言语表达困难、计算不能等症状,头颅MRI提示双侧额颞叶萎缩,以左侧为著。头颅SPECT显示:双侧额叶、颞叶和顶叶葡萄糖摄取普遍减低。PIB-PET(淀粉样蛋白PET):大脑皮质PIB显著滞留,考虑为PIB阳性显像。结论额叶变异型AD与行为变异型额颞叶痴呆临床表现类似,淀粉样蛋白PET检查可有效区分两者。     

Agitation in Alzheimer's disease is a manifestation of frontal lobe dysfunction

OBJECTIVES: (1) To investigate the prevalence and characteristics of agitation in patients with Alzheimer's disease (AD) and other forms of dementia; (2) to explore the association between agitation and other clinical variables, including disease severity, functional impairment and other neuropsychiatric symptoms, and (3) to determine the predictors of agitation. METHODS: Data for 427 men and women with dementia from outpatient clinics of the University of California, Los Angeles Alzheimer's Disease Center were analyzed. There were 277 patients with AD, 43 with vascular dementia, 47 with mixed dementia, 45 with frontotemporal dementia and 15 with dementia with Lewy bodies. Patients were evaluated with the Mini-Mental State Examination (MMSE), Neuropsychiatric Inventory (NPI), Functional Activities Questionnaire (FAQ), neuropsychological tests and the Caregiver Appraisal instrument. SPSS10 was utilized for statistical analysis. RESULTS: There was no difference in agitation subscale scores among patients with dementia of various etiologies. In patients with AD, there was increased prevalence of agitation with increasing dementia severity. Agitation contributed substantially to caregiver burden and impact. There was a significant correlation between the FAQ and the NPI agitation subscale score after adjusting for MMSE scores. Delusion, disinhibition and irritability subscale scores in AD patients were correlated with agitation across disease severity. Subscale scores of frontally mediated behaviors including irritability, delusions and disinhibition predicted most of the variance in agitation levels. CONCLUSION: Agitation is common in AD and other dementias and has a marked impact on caregivers. It is related to dementia severity and to specific types of associated psychopathology implicating frontal lobe dysfunction. The present study is the largest and most comprehensive assessment of agitation reported. The data suggest that agitation in AD is a frontal lobe syndrome. Frontal lobe dysfunction may predispose AD patients to agitation by exaggerating behavioral responses to many types of coexisting psychopathology or environmental provocations.     

Pharmacologic management of agitation in Alzheimer's disease

A large body of evidence has accrued that neuropsychiatric disturbances, such as agitation, are extremely common in Alzheimer's disease. These disturbances are associated with considerable morbidity including earlier nursing home admission, more rapid progression, exacerbation of functional and cognitive deficits, and increased caregiver distress. When attention to social or environmental causes, medical conditions, or other triggers of the behavioral disturbance fails to yield improvement, a role for medication may be indicated, whereby the most dominant behavioral target symptoms are matched to the most relevant medication class. Evidence is reviewed for various medication classes in treating agitation in the patient with Alzheimer's disease, and future treatment strategies may be aimed at delaying or preventing such neuropsychiatric disturbances.     

First symptoms--frontotemporal dementia versus Alzheimer's disease

Frontotemporal dementia (FTD) is often misdiagnosed as Alzheimer's disease (AD). We hypothesized that the first symptoms associated with FTD would be different from those seen in AD and that the first symptoms in FTD would reflect loss of function in the frontal region with the greatest degree of degeneration. The objective of the study was to compare the earliest symptoms in patients with FTD and AD, and to delineate the symptoms that were associated with right, left or bilateral frontotemporal degeneration in FTD. The first symptoms in 52 FTD and 101 AD patients were determined in retrospect. Based on functional imaging studies, the FTD patients were divided into those with predominantly bilateral (n = 15), left-sided (n = 19) and right-sided (n = 18) patterns of atrophy. The results showed that disinhibition, social awkwardness, passivity and loss of executive function were more common in FTD, while memory loss was more common in AD. Disinhibition was greatest in the asymmetric right-sided group, language dysfunction was commonest in the asymmetric left-sided group and loss of executive function was most frequent in the bilateral group. In summary, different first symptoms appeared in FTD and AD, which may help distinguish between the diseases. The anatomic site for FTD largely determined the kind of first symptoms.     

Activities of daily living in Alzheimer's disease: neuropsychiatric, cognitive, and medical illness influences.

Using a retrospective data analysis, the authors investigated the relationships between instrumental activities of daily living (IADLs) and neuropsychiatric symptoms, cognitive impairment, and medical illness burden in patients with Alzheimer's disease (AD). One hundred forty-three patients fulfilling the clinical criteria for probable or possible AD in an outpatient clinic were assessed for IADLs, neuropsychiatric symptoms, cognitive impairment, and medical illness burden with the Functional Activities Questionnaire (FAQ), Neuropsychiatric Inventory (NPI), Mini-Mental State Exam (MMSE), and Cumulative Illness Rating Scale-Geriatric (CIRS-G). Both MMSE and NPI scores related significantly to IADLs as measured by the FAQ. Several psychiatric symptoms were correlated significantly with IADLs. FAQ scores had no correlation with CIRS-G. Neuropsychiatric findings also were associated significantly with MMSE and had a weak correlation with CIRS-G scores. IADLs changed with cognition and neuropsychiatric disturbances in AD. Medical illness burden had little influence on functional status and a limited impact on neuropsychiatric symptoms.     

Omega-3 supplementation in mild to moderate Alzheimer's disease: effects on neuropsychiatric symptoms

BACKGROUND: Epidemiological and animal studies have suggested that dietary fish or fish oil rich in omega-3 fatty acids (omega3), docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), may have effects in psychiatric and behavioral symptoms in Alzheimer's disease (AD). An association with APOEomega4 carriers and neuropsychiatric symptoms in AD has also been suggested. OBJECTIVE: To determine effects of dietary omega3 supplementation to AD patients with mild to moderate disease on psychiatric and behavioral symptoms, daily functions and a possible relation to APOEgenotype. METHODS: Randomized, double-blind, placebo-controlled clinical trial where 204 AD patients (74+/-9 years) with acetylcholine esterase inhibitor treatment and a MMSE>15 points were randomized to daily intake of 1.7 g DHA and 0.6 g EPA (omega3 group) or placebo for 6 months. Then, all received the omega3 supplementation for 6 more months. Neuropsychiatric symptoms were measured with Neuropsychiatric Inventory (NPI) and Montgomery Asberg Depression Scale (MADRS). Caregivers burden and activities of daily living (Disability Assessment for Dementia, DAD) were also assessed. RESULTS: One hundred and seventy-four patients fulfilled the trial. 72% were APOEomega4 carriers. No significant overall treatment effects on neuropsychiatric symptoms, on activities of daily living or on caregiver's burden were found. However, significant positive treatment effects on the scores in the NPI agitation domain in APOEomega4 carriers (p=0.006) and in MADRS scores in non-APOEomega4 carriers (p=0.005) were found. CONCLUSIONS: Supplementation with omega3 in patients with mild to moderate AD did not result in marked effects on neuropsychiatric symptoms except for possible positive effects on depressive symptoms (assessed by MADRS) in non-APOEomega4 carriers and agitation symptoms (assessed by NPI) in APOEomega4 carriers. ClinicalTrials.gov identifier: NCT00211159     

Executive dysfunction in early Alzheimer's disease.

Twenty five patients with probable mild Alzheimer''s disease were assessed for deficits in executive functioning and the impact of these deficits on performance in other neuropsychological domains. The Wisconsin card sorting test, the release from proactive interference paradigm, the verbal fluency test, and the Stroop test were adopted to classify patients with (AD+) and without (AD-) executive deficits. Seven of the patients showed an impairment in executive function (AD+), defined as a performance below the cut off score in at least two of these tests. There were no significant differences in clinical assessments, demographic features, or other cognitive functions between patients. Executive dysfunction may be an early additional feature in a subgroup of patients with mild Alzheimer''s disease. Impairment on frontal lobe tests does not seem to be related to the severity or duration of disease, or to a different pattern of impairment in other cognitive domains.     

Cognitive and functional neuroimaging correlate for anosognosia in mild cognitive impairment and Alzheimer's disease

OBJECTIVES: To investigate the correlation between anosognosia and behavioural symptoms, performance on executive tests, and frontal cortex regional cerebral blood flow (rCBF) in patients with 'amnestic mild cognitive impairment' (MCI) and mild Alzheimer's disease (AD). METHODS: From a prospective Memory Clinic cohort including consecutively referred patients, age 60 years or above, and with MMSE score 20 or above, 36 patients with AD and 30 with MCI were included in this study. Anosognosia was assessed using a categorical scale and discrepancy scores between patients' and relatives' reports on a 20-item Memory Questionnaire (MQ). Behavioural symptoms were assessed with Frontal Behavioural Inventory (FBI). Executive functions were examined with a range of neuropsychological tests. Tc99m-HMPAO SPECT was obtained in an unselected sample of 55 of the 66 patients, and rCBF was analysed in six cortical frontal regions. RESULTS: Insight was equally impaired in the two patient groups. A significant correlation was found between impaired awareness and dementia severity (MMSE). Discrepancy-scores on the MQ were significantly correlated to scores on FBI and to rCBF in the right inferior frontal gyrus, but not to executive tests. The groups classified by the categorical ratings 'full', 'shallow' and 'no' awareness were not characterized by differences in behavioural symptoms, executive performance or frontal rCBF. CONCLUSIONS: Impaired awareness is associated with behavioural symptoms and may reflect functional impairment in the right inferior frontal cortex.     

Neuropsychiatric symptoms, functional impairment and executive ability in Thai patients with Alzheimer's disease

BACKGROUND: Instrumental activities of daily living (IADL) depend on executive planning and procedural memory mediated by the frontal lobes. Planning and judgment are involved in clock drawing. Neuropsychiatric symptoms are also mediated by frontal lobes, and a relationship between ADL, clock drawing and neuropsychiatric symptoms was hypothesized. OBJECTIVE: To investigate the relationship between behavioral disturbances, ADL, and executive function. METHODS: Seventy-three Thai patients with Alzheimer's disease (AD) were evaluated. Neuropsychiatric symptoms and behaviors were assessed with the Nevropsychiatric Inventory (NPI). The Thai version of the Mini-mental State Examination (TMSE) was utilized as a global cognitive assessment. A clock-drawing test (CDT) and both category (animals) and letter (ko, so in Thai) verbal fluency were used as executive measures. Thai ADL scale, Barthel Index (BI), and Functional Assessment Questionnaire (FAQ) were ADL measures used in this study. RESULTS: There were statistically significant correlations between CDT and the frontally-mediated behaviors of agitation (r = -0.367), apathy (r = -0.273) and disinhibition (r = -0.247). Verbal fluency correlated with agitation (r = -0.341). There were significant correlations between Thai ADL scores and agitation (r = 0.350), apathy (r = 0.441), and disinhibition (r = 0.417). FAQ correlated with the same three behaviors. After controlling for TMSE, a significant correlation remained between Thai ADL scores and agitation (r = 0.291) and apathy (r = 0.342). CONCLUSIONS: We demonstrated correlations between ADL and behavioral changes in Thai elderly with AD. Our results emphasize the important relationships among behavioral changes and impaired ADL.     

The construct of minor and major depression in Alzheimer's disease

OBJECTIVE: This study examined the frequency of major and minor depression in Alzheimer's disease and determined whether these types of depression have a different functional and psychopathological impact and whether there is a change in the prevalence of major and minor depression throughout the stages of Alzheimer's disease. METHOD: A consecutive series of 670 patients with probable Alzheimer's disease were assessed with the Structured Clinical Interview for DSM-IV; specific instruments to rate the presence and severity of depression, anxiety, apathy, irritability, delusions, pathological affective crying, performance of activities of daily living, and social functioning; and a standardized neuropsychological evaluation. Diagnoses of major and minor depression were generated from DSM-IV criteria. RESULTS: Twenty-six percent of the patients had major depression, 26% had minor depression, and 48% were not depressed. Major depression was significantly associated with sad mood in all three stages of the illness, although this association dropped significantly for minor depression in severe Alzheimer's disease. Both major and minor depression were significantly associated with more severe psychopathology, functional impairments, and social dysfunction. Depressive symptoms that most strongly discriminated between Alzheimer's disease patients with and without sad mood were guilty ideation, suicidal ideation, loss of energy, insomnia, weight loss, psychomotor retardation/agitation, poor concentration, and loss of interest. CONCLUSIONS: Our study demonstrates that DSM-IV criteria for major and minor depression identify clinically relevant syndromes of depression in Alzheimer's disease, mild levels of depression can produce significant functional impairment, and the severity of psychopathological and neurological impairments increases with increasing severity of depression.     

Treating apathy in Alzheimer's disease

Apathy, a syndrome of decreased initiation and motivation, affects over 70% of individuals with Alzheimer's disease (AD) and is the most common neuropsychiatric symptom reported in AD patients. The syndrome of apathy is associated with functional impairment among patients and elevated stress among their caregivers. Apathy is one of the primary neuropsychiatric manifestations of frontal system dysfunction, and AD-related apathy is thought to reflect the interaction between cholinergic deficiency and neuropathological changes in frontal brain regions. This article reviews the assessment and treatment of apathy in AD, with emphasis on the utility of acetylcholinesterase inhibitors for reducing apathy in AD. The potential benefits of other pharmacologic agents and combined pharmacologic-behavioral interventions are also discussed, and recommendations for future research are provided.     

White matter changes associated with psychotic symptoms in Alzheimer's disease patients

This study explored the relationship between white matter changes seen on magnetic resonance imaging (MRI) and neuropsychiatric symptoms of Alzheimer's disease patients. Fifty-five probable Alzheimer's disease patients were assessed with Behavioral Rating Scale for Dementia (BRSD) and MRI. White matter changes in the bilateral frontal or parieto-occipital region and left basal ganglia significantly corresponded with the score of the Psychotic Symptoms subscale of BRSD. Secondary analyses revealed that white matter changes were not associated with paranoid delusion and hallucination, but only with delusional misidentification. Our results suggest that white matter changes in Alzheimer's disease patients probably contribute to the development of specific psychotic symptoms, namely delusional misidentification.