Dementia Rating Scale Performance: A Comparison of Vascular and Alzheimer's Dementia

Differences in the pattern of neuropsychological dysfunction associated with Alzheimer's disease (AD) and vascular dementia (VaD) were examined using the Dementia Rating Scale (DRS). We examined three groups of patients: (1) Patients with AD; (2) patients with single stroke (CVA); and (3) patients with multiple cerebral infarctions (MI). Comparisons of cognitive dysfunction were conducted on patients that met the DRS criteria for dementia. Dementia groups were similar in age, education, and severity of dementia. Comparisons of the AD and two VaD groups across the specific DRS-scales (Attention, Conceptualization, Construction, Initiation/Perseveration, and Memory) indicated that patients with AD were more impaired on the DRS-Memory while the patients with VaD were more impaired on the DRS-Construction. Additionally, patients with VaD related to MI scored lower on the DRS-Initiation/Perseveration as compared to patients with AD, and patients with AD scored lower on the DRS-Conceptualization as compared to patients with VaD related to CVA. These results are indicative of qualitative differences in the pattern of cognitive deficits associated with the two types of dementia.     

Sensitivity of the dementia rating scale in vascular dementia: comparison between two sets of criteria to define cognitive impairment

BACKGROUND: The Dementia Rating Scale (DRS) is a common measure of cognitive function, but its sensitivity to identify deficits across cognitive domains in vascular dementia (VaD) remains unclear. METHODS: We compared the sensitivity and specificity of two recommended cutoff scores of the DRS. Thirty-eight patients diagnosed with VaD participated in the current study. RESULTS: The original recommendations resulted in poor sensitivity for the DRS total score and attention, construction, and memory subscales. The more recent recommendations greatly improved the sensitivity of the subscales and the total DRS score, but resulted in decreased specificity. Correlations between the specific DRS subscales and criterion measures of cognitive function revealed good convergent and divergent validity for most subscales. CONCLUSIONS: The DRS is a valid measure of cognitive dysfunction in VaD, but clinicians should consider using the more recent recommendations developed for AD to determine impaired performances in VaD.     

Cognitive predictors of functional decline in vascular dementia

BACKGROUND: This study examined changes in cognitive-functional relationships in vascular dementia (VaD) over the course of one year. METHODS: Twenty-four patients with probable VaD were administered the Dementia Rating Scale (DRS). Caregivers completed an informant-based measure of instrumental (IADL) and basic activities of daily living (BADL). Follow-up assessment was conducted one-year post-baseline. RESULTS: Logistic regression revealed that changes in the DRS Initiation/Perseveration and DRS Memory subscales were significantly associated with declines in IADLs and BADLs, respectively. CONCLUSIONS: Among patients with VaD, longitudinal changes in IADLs and BADLs are most strongly associated with changes in executive functioning and memory abilities, respectively. Findings suggest that different cognitive functions subserve complex instrumental and rote, habituated basic functional activities, and neuropsychological screening measures are useful in the prediction of such functional changes.     

Linguistic abilities in major vascular cognitive impairment: a comparative study with Alzheimer’s disease

We assessed the linguistic abilities of multi-infarct (cortical) dementia and subcortical ischemic vascular dementia (VaD) patients and compared the linguistic performance of VaD and Alzheimer’s Disease (AD) patients. A total of 23 VaD patients, 20 mild AD patients, and 31 controls participated in the study. All were evaluated using the Arizona Battery for Communication Disorders of Dementia (ABCD). Neuropsychological testing was performed to ascertain that VaD and AD patients had comparable cognitive performance. Both dementia groups performed more poorly than controls in the ABCD measures, except for the comparative question subtest. Comparison between VaD and AD patients showed statistically significant differences only in the confrontation naming subtest (p?<?0.05), where paraphasias and visual errors were the most prevalent. AD patients showed a trend towards more circumlocution errors than VaD patients (p?=?0.0483). When compared to controls, linguistic abilities of VaD patients were impaired in all measures of linguistic expression and linguistic comprehension, except for the comparative question subtest. Linguistic differences between VaD and AD patients were observed only in the confrontation naming subtest.     

Cognitive and functional decline in African Americans with VaD, AD, and stroke without dementia.

OBJECTIVE: To compare the rates of cognitive and functional decline in African American patients diagnosed at baseline with vascular dementia (VaD) (n = 79), AD (n = 113), or stroke without dementia (SWD) (n = 56) and followed for up to 7 years with annual neuropsychological and other examinations. METHODS: Study patients were diagnosed using established criteria for dementia and were administered cognitive screening, functional screening, and neuropsychological measures. Baseline dementia severity was rated using the Clinical Dementia Rating Scale. Random effects modeling was used to examine rates of decline and to compare the rates of decline in the three groups. RESULTS: Both patients with VaD and those with AD showed significant cognitive and functional decline during follow-up; patients with VaD declined at a slower rate than patients with AD; and patients diagnosed with SWD at baseline did not show cognitive or functional decline during follow-up. CONCLUSIONS: Patients with VaD decline at a slower rate than patients with AD. Patients who do not meet criteria for dementia soon after stroke may not be at high risk for developing dementia. Future studies are needed to follow VaD patients with longitudinal, specialized MR protocols, concurrent neuropsychological examinations, and neuropathologic examination to determine possible neuroimaging predictors of progressive cognitive and functional decline and to assess the contribution of Alzheimer's pathology to decline in patients diagnosed with VaD.     

Cognitive and neurologic predictors of functional impairment in vascular dementia.

OBJECTIVE: The purpose of this study is to investigate associations between executive dysfunction, neuroimaging findings, and functional impairment in patients with vascular dementia (VaD). METHODS: Twenty-nine VaD patients completed the Dementia Rating Scale and underwent MRI scanning to generate quantitative ratings of subcortical hyperintensities (SH) and cortical volume. Patients' caregivers completed items from the Lawton and Brody Activities of Daily Living Questionnaire, designed to measure instrumental activities of daily living (IADLs). The authors hypothesized that performance on the Initiation/Perseveration (IP) subscale, a measure of executive abilities, and SH would significantly predict levels of IADLs. RESULTS: A hierarchical multiple-regression analysis revealed that IP and SH accounted for 42% of the variance in IADLs; IP alone accounted for 28%, and SH accounted for 14% beyond the contribution made by IP. CONCLUSION: Findings indicate that specific cognitive and neuropathological factors are associated with functional impairment in VaD.     

Effects of depression and Parkinson's disease on cognitive functioning

This study compared the performance of Parkinson's disease (PD) patients with and without depression, patients with depression alone, and normal control subjects on a cognitive screening instrument, the Mattis Dementia Rating Scale (DRS) to evaluate the influences of depression and Parkinson's disease on cognition. PD affects overall level of cognitive functioning and, to a lesser extent, DRS Initiation/Perseveration, Construction, and Attention. Diminished memory was primarily related to depression. Treatment of depression may ameliorate aspects of cognitive dysfunction in the PD patient with depression.     

High b-value diffusion imaging of dementia: application to vascular dementia and alzheimer disease

Alzheimer's disease (AD) and Vascular Dementia (VaD) are the most common types of dementia and are progressive diseases affecting millions of people. Despite the high sensitivity of MRI to neurological disorders it has not thus far been found to be specific for the detection of either of these pathologies. In the present study high b-value q-space diffusion-weighted MRI (DWI) was applied to VaD and AD. Controls (N=4), VaD patients (N=8) and AD patients (N=6) were scanned with high b-value DWI, which emphasizes the water component which exhibits restricted diffusion. VaD patients were found to present major WM loss while, in AD, the major pathology found was GM changes, as expected. Also, WM changes in VaD and AD were of a different pattern, more specific to frontal and temporal areas in AD and more widespread in VaD. This pattern of WM changes may be utilized as a diagnosis criterion. Conventional diffusion tensor imaging did not show significant changes between either of the groups and controls. These results demonstrate the potential of high b-value DWI in the diagnosis of dementia.     

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.     

Screening for Dementia: Comparison of Three Commonly Used Instruments

The sensitivity and specificity of three cognitive screening measures – the Mini-Mental State Exam (MMSE), Mattis Dementia Rating Scale (MDRS), and Neurobehavioral Cognitive Status Examination (NCSE) – were compared in a cohort of subjects with dementia as well as normal elderly individuals. Twenty-two patients met criteria for probable Alzheimer's disease (AD), 19 for vascular dementia (VaD), and 12 were normal control subjects. The use of standard cutpoints resulted in poor to good classification accuracy for the three measures, but measurable improvement in sensitivity was obtained by adjusting the cutpoints for each measure. Discriminatory power was maximized with an MMSE cutpoint of 26, an MDRS cutpoint of 134, and requiring one or more NCSE subtests to be in the impaired range. Use of age and education adjusted norms resulted in good to excellent classification accuracy for the MMSE and MDRS. The NCSE subtest score pattern failed to differentiate between AD and VaD.     

Screening for dementia: comparison of three commonly used instruments.

The sensitivity and specificity of three cognitive screening measures - the Mini-Mental State Exam (MMSE), Mattis Dementia Rating Scale (MDRS), and Neurobehavioral Cognitive Status Examination (NCSE) - were compared in a cohort of subjects with dementia as well as normal elderly individuals. Twenty-two patients met criteria for probable Alzheimer' s disease (AD), 19 for vascular dementia (VaD), and 12 were normal control subjects. The use of standard cutpoints resulted in poor to good classification accuracy for the three measures, but measurable improvement in sensitivity was obtained by adjusting the cutpoints for each measure. Discriminatory power was maximized with an MMSE cutpoint of < or = 26, an MDRS cutpoint of < or = 134, and requiring one or more NCSE subtests to be in the impaired range. Use of age and education adjusted norms resulted in good to excellent classification accuracy for the MMSE and MDRS. The NCSE subtest score pattern failed to differentiate between AD and VaD.     

Vascular dementia and Alzheimer's disease: is there a difference? A comparison of symptoms by disease duration

This study examined differences between vascular dementia (VaD) by the NINDS/AIRENS criteria and Alzheimer's disease (AD) on clinical grounds. A consecutive series of 517 patients with probable and possible VaD or AD were evaluated for cognitive, functional, and behavioral symptoms and separated into three subgroups by duration of dementia. These AD and VaD subgroups were then compared on a series of standardized clinical measures. The only consistent trends were for VaD patients to be more depressed, more functionally impaired, and less cognitively impaired within each disease duration subgroup. The authors conclude that there are few differences between clinically diagnosed VaD and AD. Subclassification of VaD into subgroups will improve the clinical utility of this nosologic entity.     

CT brain findings in clinical dementia investigation--underestimation of mixed dementia

Dementia has been found to display a more heterogeneous clinical picture than previously recognized. We investigated brain changes on computed tomography (CT) in a clinical dementia population consisting of 67 cases with Alzheimer's disease (AD), 13 with mixed dementia (AD and vascular dementia, VaD), 71 with VaD, and 12 cases that were not demented. Temporal cortical atrophy and atrophy around the temporal horns were more common in patients with mixed dementia compared to patients with VaD and the non-demented, respectively. Frontal white matter changes were present in 64% of AD, in 85% of mixed dementia and in 79% of VaD cases, but there were no differences between the dementia groups. Lacunes were present in almost 40% of AD cases and in 80 and 85% of VaD and mixed dementia cases, respectively. Only 14% of the VaD cases had large infarcts on the CT. We conclude that large infarcts were rare, even in VaD cases. The increased incidence of white matter changes and lacunes in AD patients strongly indicates an underestimation of the mixed dementia diagnosis. More distinct criteria for this diagnostic category are warranted.     

Validity of the Dementia Rating Scale in assessing cognitive function in Parkinson's disease

Two studies examined the validity of the Dementia Rating Scale (DRS) as a measure of cognitive functioning among patients with Parkinson's disease (PD). The DRS accounted for more variation in the level of cognitive functioning of PD patients than either the Mini-Mental Status Examination or a battery of tests selected to assess specific cognitive deficits associated with PD. Further, DRS subtests displayed strong convergent and discriminant validity with a comprehensive Criterion Neuropsychology Battery. The DRS subtests appear to be valid measures of attention, perseveration, conceptualization, and memory among PD patients. However, the DRS-Construction subtest should be supplemented with additional visuoconstructional items to provide a thorough screen of cognitive functioning in PD. Although about three-quarters of nondemented PD patients did not appear to have any specific cognitive deficits on the DRS, the remaining patients were impaired on the Construction or Initiation/Perseveration subtests of the DRS. In summary, the DRS is a valid mental status screening test of cognitive functioning for individuals with PD.     

Behavioral regulation: factor analysis and application of the Behavioral Dyscontrol Scale in dementia and mild cognitive impairment

BACKGROUND: Executive dysfunction is a hallmark of both Dementia of the Alzheimer's Type (AD) and Vascular Dementia (VaD). A complete neuropsychological battery contains measures of executive function, but the focus tends to be on cognitive processes with verbal or written output. The Behavioral Dyscontrol Scale (BDS) is purported to be a measure of executive function that addresses control over voluntary motor behavior. Previous factor analyses revealed three-factor solutions using a variety of patient populations. Our goals were to examine the factor structure in a sample of geriatric outpatients and to apply that factor structure to detect possible differences between AD, VaD, amnestic Mild Cognitive Impairment (MCI), non-amnestic MCI, and normal controls. METHODS: An exploratory factor analysis was performed on 260 outpatient evaluations from 2002-2006. Only the seven items requiring motor responses were included. RESULTS: A two-factor solution emerged. We named the factors Motor Problem-Solving and Simple Motor Repetitive Behaviors. For the first factor, the AD and VaD groups differed from the MCI groups and normal controls, but did not differ from each other. There were no differences between the control, amnestic MCI, and non-amnestic MCI groups. There were no differences between the groups for the second factor. CONCLUSION: It was concluded that voluntary control of behavior that requires problem-solving for complex tasks may help differentiate dementia from mild cognitive impairment and normal aging.     

Long-term safety and cognitive effects of galantamine in the treatment of probable vascular dementia or Alzheimer's disease with cerebrovascular disease.

The relationship between cholinergic dysfunction and cognitive and functional impairment in patients with vascular dementia (VaD) and Alzheimer's disease (AD) with cerebrovascular disease (CVD) suggests a potential role for cholinomimetic therapy. Initial studies of galantamine demonstrated cognitive, behavioral, and functional benefits in these populations. 326 patients with VaD or AD with CVD who completed an initial 12-month trial were treated with galantamine 24 mg/day in a 24-month, open-label extension. This interim analysis was performed at month 12 of the open-label extension (248 completed the trial). Galantamine (up to 24 months total) was well tolerated in both groups. The most frequently reported adverse events, characteristic of older dementia patients, included depression, agitation, and insomnia. Gastrointestinal adverse events were less common than initially, indicating declining incidence with long-term therapy. Patients taking galantamine for the entire study demonstrated the least cognitive decline on AD Assessment Scale-cog/11: 2.7 points vs. 3.1 points in those given placebo initially (P < 0.001 and P = 0.003, respectively). The long-term benefits of galantamine were evident in both groups; cognitive baseline levels were maintained for approximately 21 months in VaD patients and for 12 months in patients with AD with CVD. Long-term (up to 24 months) galantamine therapy in patients with VaD and AD with CVD is well tolerated and associated with prolonged maintenance of cognitive function.     

Similar patterns of cognitive deficits in the preclinical phases of vascular dementia and Alzheimer's disease.

We investigated whether (1) cognitive deficits are present among persons who will be diagnosed with vascular dementia (VaD) 3 years later, and (2) the pattern of such deficits is similar to that observed in preclinical Alzheimer's disease (AD). The VaD diagnosis was a diagnosis of post-stroke dementia. Population-based samples of 15 incident VaD cases, 43 incident AD cases, and 149 normal controls were compared on tests of episodic and short-term memory, verbal fluency, and visuospatial skill. Both dementia groups showed preclinical impairment relative controls on tasks assessing episodic memory 3 years before diagnosis, and there were no differences between these groups on any cognitive measure. The existence of a preclinical phase in the present VaD cases suggests that circulatory disturbance may affect cognitive performance before the occurrence of stroke that leads to clinical VaD. These results extend previous findings of similar patterns of cognitive deficits in the early clinical phases of AD and VaD to the preclinical phases of these diseases.     

Dementia with leukoaraiosis: clinical differentiation by temporoparietal hypometabolism on (18)FDG-PET imaging

Patients with dementia and leukoaraiosis may have either Alzheimer's disease (AD) with cerebrovascular changes or a form of vascular dementia (VaD). The presence or absence of the characteristic AD pattern of bilateral temporoparietal hypometabolism on (18)FDG-PET was used to differentiate 30 patients with progressive dementia and severe leukoaraiosis. Compared to 18 patients with the typical AD pattern (group I), the remaining 12 (group II) had better recognition memory, and greater difficulty with sustained attention and serial reversals. Better recognition memory, confluent periventricular leukoaraiosis, and poorer sustained attention distinguished all group II patients from group I. Dementia patients with severe leukoaraiosis and bilateral temporoparietal hypometabolism may have predominant AD; those who lack this pattern and have confluent leukoaraiosis may have a greater contribution from VaD. Copyrightz1999S.KargerAG,Basel     

Cognitive outcome measures

Clinical trials of antidementia drugs must use a performance-based cognitive assessment as a primary outcome measure. There are well-established criteria for selecting or developing an optimal cognitive battery for Alzheimer disease (AD) trials that also apply to vascular dementia (VaD) trials. Because there is substantial overlap between the pattern of cognitive impairment in VaD and AD, the most efficient strategy for developing a VaD battery would be to begin with a well-established AD instrument and add subtests covering the additional domains that are more prominently impaired in VaD.