Dementia Of The Alzheimer Type Group Research Articles

Mild Cognitive Impairment Represents Early-Stage Alzheimer Disease

Mild cognitive impairment (MCI) is considered to be a transitional stage between aging and Alzheimer disease (AD). To determine whether MCI represents early-stage AD by examining its natural history and neuropathologic basis. A prospective clinical and psychometric study of community-living elderly volunteers, both nondemented and minimally cognitively impaired, followed up for up to 9.5 years. Neuropathologic examinations were performed on participants who had undergone autopsy. An AD research center. All participants enrolled between July 1990 and June 1997 with Clinical Dementia Rating (CDR) scores of 0 (cognitively healthy; n = 177; mean age, 78.9 years) or 0.5 (equivalent to MCI; n = 277; mean age, 76.9 years). Based on the degree of clinical confidence that MCI represented dementia of the Alzheimer type (DAT), 3 subgroups of individuals with CDR scores of 0.5 were identified: CDR 0.5/DAT, CDR 0.5/incipient DAT, and CDR 0.5/uncertain dementia. Progression to the stage of CDR 1, which characterizes mild definite DAT. Survival analysis showed that 100% of CDR 0.5/DAT participants progressed to greater dementia severity over a 9.5-year period. At 5 years, rates of progression to a score of CDR 1 (or greater) for DAT were 60.5% (95% confidence interval [CI], 50.2%-70.8%) for the CDR 0.5/DAT group, 35.7% (95% CI, 21.0%-50.3%) for the CDR 0.5/incipient DAT group, 19.9% (95% CI, 8.0%-31.8%) for the CDR 0.5/uncertain dementia group, and 6.8% (95% CI, 2.2%-11.3%) for CDR 0/controls. Progression to greater dementia severity correlated with degree of cognitive impairment at baseline. Twenty-four of the 25 participants with scores of CDR 0.5 had a neuropathologic dementing disorder, which was AD in 21 (84%). Individuals currently characterized as having MCI progress steadily to greater stages of dementia severity at rates dependent on the level of cognitive impairment at entry and they almost always have the neuropathologic features of AD. We conclude that MCI generally represents early-stage AD.

Alzheimer disease constricts the dynamic range of spatial attention in visual search

A cued visual search task was used to examine the dynamic range over which spatial attention affects target identification during visual search. Precues varied in validity (valid, invalid, or neutral) and in precision (cue size) of target localization. Participants were “young-old” (65–74 years) and “old-old” (75–85 years) elderly adults and individuals in the mild stage of dementia of the Alzheimer type (DAT). For all participants, search was speeded as the precision with which a precue surrounding the location of a subsequently appearing target increased (precue size decreased). The cue size effect was evident in both feature and conjunction search, but was greatly reduced in both old-old and DAT groups compared to the young-old. However, whereas all non-demented adults showed a progressive modulation of search efficiency over the entire range of cue sizes, the dynamic range of spatial attention was restricted to the most precise cue in the DAT group. The restriction in the dynamic range of spatial attention may represent an underlying component of the impairment in perceptual and memory functioning found in early-stage DAT.

Characteristics of motor vehicle crashes of drivers with dementia of the Alzheimer type.

To determine whether there is a difference in crash rates and characteristics between drivers with dementia of the Alzheimer type (DAT) and nondemented older persons who were controls. A pilot study using a 5-year retrospective analysis of state-recorded crash data and crash characteristics followed by patient enrollment into a study on road test skills. Alzheimer's Disease Research Center at Washington University in St. Louis, Missouri. Subjects were enrolled as volunteers in a longitudinal study of aging and DAT. One hundred twenty-one subjects (58 nondemented, older drivers and 63 drivers with DAT) with a mean age of 77 years met the inclusion criteria for this study. DAT was diagnosed using validated clinical diagnostic criteria and was staged by the Clinical Dementia Rating (CDR) Scale. All subjects with DAT were in the very mild (CDR = 0.5) or mild (CDR = 1) stages. State-recorded traffic crashes. Also, a daily driving diary was completed by each subject and used to estimate miles traveled per year. Subjects diagnosed with mild DAT (CDR = 1) reported less roadway exposure (average number of miles driven per year) than did drivers with very mild DAT (CDR = 0.5) or controls. Crashes in both groups were infrequent, with 0.07 state-recorded crashes per driver per year in the nondemented group (CDR = 0), 0.06 in the very mild DAT group (CDR = 0.5), and 0.04 in the mild DAT group (CDR = 1). There was no statistical difference in the crash frequency between groups, even when adjusting for exposure. Drivers with DAT had trends toward more at-fault crashes, crashes with injuries, and crashes in which the officer on the scene cited failure to yield. In our sample, individuals with very mild or mild DAT who continued to drive seemed to have crash rates similar to those of the controls. There may be significant differences between the causes and the consequences of crashes involving drivers with DAT when compared with cognitively intact age-matched controls, but none were found in this pilot study. Further research on crash characteristics is needed in larger samples of community-based drivers with DAT across wider ranges of dementia severity to address issues such as driving competency and public safety.

Differentiation of Dementia of the Alzheimer's Type From Depression With Cognitive Impairment on the Basis of a Cortical Versus Subcortical Pattern of Cognitive Deficit

This study compared 15 "mildly" cognitively impaired participants with Dementia of the Alzheimer Type (DAT), 15 depressed cognitively impaired participants (DCI), and 15 normal participants. The participants were matched for age, and reading ability, and were tested on a series of cognitive instruments selected on the basis of their ability to distinguish a cortical versus subcortical pattern of deficit. The DAT group demonstrated impaired performances on tests of language, praxis and gnosis. Deficits in these areas were absent from DCI group. There were differences between all of the groups on the California Verbal Learning Test, but after this effect was controlled using an analysis of covariance procedure, the differences in tests of gnosis, praxis and language function between the DCI and the DAT participants still remained. These findings support the clinical usefulness of the cortical-subcortical distinction in differentiating DCI from DAT.

Differentiation of Dementia of the Alzheimer's Type From Depression With Cognitive Impairment on the Basis of a Cortical Versus Subcortical Pattern of Cognitive Deficit

This study compared 15 “mildly” cognitively impaired participants with Dementia of the Alzheimer Type (DAT), 15 depressed cognitively impaired participants (DCI), and 15 normal participants. The participants were matched for age, and reading ability, and were tested on a series of cognitive instruments selected on the basis of their ability to distinguish a cortical versus subcortical pattern of deficit. The DAT group demonstrated impaired performances on tests of language, praxis and gnosis. Deficits in these areas were absent from DCI group. There were differences between all of the groups on the California Verbal Learning Test, but after this effect was controlled using an analysis of covariance procedure, the differences in tests of gnosis, praxis and language function between the DCI and the DAT participants still remained. These findings support the clinical usefulness of the cortical-subcortical distinction in differentiating DCI from DAT.

General Slowing of Lexical and Nonlexical Information Processing in Dementia of the Alzheimer Type

Individuals with very mild and mild dementia of the Alzheimer type (DAT) and age-matched controls performed three lexical and three nonlexical speeded information-processing tasks. The DAT group was slower than the control group on all six tasks. As predicted by general slowing (Nebes & Brady, 1992), most main effects of task condition were accompanied by Group × Condition interactions. That is, as task complexity increased, the response times (RTs) of the DAT group increased more than the RTs of the control group. Multitask regression analyses confirmed the existence of general slowing in DAT, such that the DAT group took approximately 1.8 times as long to process information as the controls on all six tasks. Importantly, lexical and nonlexical processing speed were equivalently affected by DAT. This pattern was observed both in very mild and mild DAT, although the degree of general slowing increased with the severity of the dementia.

Relating anatomy to function in Alzheimer's disease: neuropsychological profiles predict regional neuropathology 5 years later.

Neuropsychological profiles were assessed in a large group of nondemented control subjects (n = 261) and individuals with dementia of the Alzheimer type (DAT) (n = 407) by subjecting their psychometric test results to a factor analysis. Nondemented control subjects were functionally homogeneous with only one factor accounting for the results. The results of the factor analysis on the very mild DAT and mild DAT groups, however, yielded a mental control/frontal factor, a memory-verbal/temporal factor, and a visuospatial/parietal factor. Forty-one of the original set of participants came to autopsy an average of 5.1 years after psychometric testing and had neurofibrillary tangles, total senile plaques, and cored senile plaques estimated from frontal, temporal, and parietal regions. The results of correlations indicated that the relative burden of cored senile plaques was systematically related to the three psychometric factors. These results suggest a connection between the specific functions as defined by neuropsychological measures and specific neuropathology occurring in associated areas of cortex.

Quantitative Anatomic Measures and Comorbid Medical Illness in Late-Life Major Depression

The authors examined the individual and relative roles of atrophy, comorbid medical illness, and cerebrovascular risk factors in the pathogenesis of late-life major depressive disorder (MDD). They used magnetic resonance imaging techniques to study 28 subjects with late-life MDD, 29 healthy control subjects, and 34 subjects with probable dementia of the Alzheimer type (DAT). Depressed subjects showed increases in cerebrospinal fluid volumes comparable to the DAT group but significantly different from control subjects. High-intensity signals, but not measures of atrophy correlated significantly with cerebrovascular risk factor scores. A logistic regression revealed that both brain atrophy and medical illness are associated with an increased risk of developing MDD. Data suggest that both atrophy and comorbid medical illness increase the likelihood of developing MDD in late life.

Brain perfusion scintigraphy with99mTc-HMPAO or99mTc-ECD and123I-β-CIT single-photon emission tomography in dementia of the Alzheimer-type and diffuse Lewy body disease

Dementia of the Alzheimer-type (DAT) is characterized by progressive cognitive decline, variably combined with frontal lobe release signs, parkinsonian symptoms and myoclonus. The features of diffuse Lewy body disease (DLBD), the second most common cause of degenerative dementia, include progressive cognitive deterioration, often associated with levodopa-responsive parkinsonism, fluctuations of cognitive and motor functions, psychotic symptoms (visual and auditory hallucinations, depression), hypersensitivity to neuroleptics and orthostatic hypotension. A recent report suggests that positron emission tomography studies in patients with degenerative dementia may be useful in the differential diagnosis of DAT and DLBD. However, the diagnostic role of single-photon emission tomography (SPET) studies remains to be established. The aim of this study was therefore to evaluate regional cerebral perfusion [with either technetium-99m hexamethylpropylene amine oxime (99mTc-HMPAO) or 99mTc-ethyl cysteinate dimer (99mTc-ECD) SPET] and striatal dopamine transporter density [using iodine-123 2 beta-carboxymethoxy-3 beta-[4-iodophenyl]tropane (123I-beta-CIT) SPET] in patients with DAT and DLBD. Six patients with probable DAT and seven patients with probable DLBD were studied. Blinded qualitative assessment by four independent raters of 99mTc-HMPAO or 99mTc-ECD SPET studies revealed bilateral temporal and/or parietal hypoperfusion in all DAT patients. There was additional frontal hypoperfusion in two patients and occipital hypoperfusion in one patient. In the DLBD group, regional cerebral perfusion had a different pattern. In addition to temporoparietal hypoperfusion there was occipital hypoperfusion resembling a horseshoe defect in six of seven patients. In the DAT group, the mean 3-h striatal/cerebellar ratio of 123I-beta-CIT binding was 2.5 +/- 0.4, with an increase to 5.5 +/- 1.1 18 h after tracer injection. In comparison, in the DLBD patients the mean 3-h striatal/cerebellar ratio of 123I-beta-CIT binding was significantly reduced to 1.7 +/- 0.3, with a modest increase to 2.1 +/- 0.4 18 h after tracer injection (P < 0.05, Scheffe test, ANOVA). These results suggest that 99mTc-HMPAO or 99mTc-ECD and 123I-beta-CIT SPET may contribute to the differential diagnosis between DAT and DLBD, showing different perfusion patterns and more severe impairment of dopamine transporter function in DLBD than in DAT.

Generation effects and source memory in healthy older adults and in adults with dementia of the Alzheimer type.

Recognition and source memory were explored in healthy older adults, adults diagnosed with very mild dementia of the Alzheimer type (DAT), and adults diagnosed with mild DAT. Two sentence-completion tasks were used. In Task 1, half of the sentences were completed (clozed) by the participant, and half by the experimenter. In Task 2, half were participant clozed, and half were participant read (already clozed). Recognition of the cloze words and accuracy of categorizing them as participant generated or experimenter generated (Task 1) and participant generated or participant read (Task 2) were measured (source discrimination). Contrary to previous reports, the DAT groups showed the generation effect, that is, better recognition for participant-generated words than experimenter-generated words (Task 1) or read words (Task 2). Source discrimination was disproportionately impaired in the DAT groups.

Generation effects and source memory in healthy older adults and in adults with dementia of the Alzheimer type.

Recognition and source memory were explored in healthy older adults, adults diagnosed with very mild dementia of the Alzheimer type (DAT), and adults diagnosed with mild DAT. Two sentence-completion tasks were used. In Task 1, half of the sentences were completed (clozed) by the participant, and half by the experimenter. In Task 2, half were participant clozed, and half were participant read (already clozed). Recognition of the cloze words and accuracy of categorizing them as participant generated or experimenter generated (Task 1) and participant generated or participant read (Task 2) were measured (source discrimination). Contrary to previous reports, the DAT groups showed the generation effect, that is, better recognition for participant-generated words than experimenter-generated words (Task 1) or read words (Task 2). Source discrimination was disproportionately impaired in the DAT groups.

Longitudinal examination of American National Adult Reading Test (AMNART) performance in dementia of the Alzheimer type (DAT): validation and correction based on degree of cognitive decline.

The American National Adult Reading Test (AMNART) was constructed to provide a valid and stable estimate of premorbid verbal IQ (VIQ) in dementing individuals. However, recent studies have brought into question its validity in patients with dementia of the Alzheimer type (DAT). The present study was designed to longitudinally assess the validity of the AMNART in 40 DAT patients and 40 demographically matched normal control (NC) subjects. The results showed that VIQ estimates for patients with DAT were significantly lower than those of NC subjects and declined significantly over time with increasing dementia severity as measured by the Mini-Mental State Examination (MMSE) and the Dementia Rating Scale (DRS). An MMSE-based correction factor was derived for the DAT group which allows for the effective estimation of premorbid VIQ in these patients.

Patterns of neuropsychological impairment in dementia of the Alzheimer type and multi-infarct dementia.

Patterns of performance on 22 neuropsychological tests were examined in 58 patients with presumed dementia of the Alzheimer type (DAT) and 58 patients with presumed multi-infarct dementia (MID). Few differences between patterns of performance in DAT and MID were found when overall level of performance was taken into account. Within the DAT group, there were some age-related differences in performance that in themselves might support other studies suggesting clinical and neuropathological differences between subtypes of DAT that are related in part to the age at which the condition occurs. However, similar age-related patterns were found in the MID group and the DAT and MID groups did not differ significantly in this respect. Considerable inter-individual variability in pattern of performance was apparent within each group. A proportion of patients were re-assessed 10 months after initial assessment: the extent of decline over time was not predictable from patients' characteristics or test performances at initial assessment. 'De-differentiation' in patterns of impairment, over time or with increasing severity of impairment, was not observed.

Lexical and Nonlexical Spelling Deficits in Dementia of the Alzheimer Type

Written spelling was assessed in 16 subjects with dementia of the Alzheimer type (DAT) using an information processing approach. The results were compared to the performance in a group of healthy elderly subjects. The Alzheimer subjects scored significantly lower in word spelling and nonword spelling ability than the controls (F(1, 7) = 187,p< .0001), and both the lexical and the nonlexical spelling strategies were affected. The results did not support the hypothesis that nonlexical ability is preserved in DAT. In the DAT group, spelling correlated significantly (p< 0.01) with the severity of dementia, but spelling performance was not associated with the age of onset of dementia or family history of dementia.

1995 IPA/Bayer Research Awards in Psychogeriatrics. Bihemispheric language disorders in early-stage dementia of the Alzheimer type: evidence from a novel metalinguistic task.

Because dementia of the Alzheimer type (DAT) is commonly characterized by bilateral cerebral atrophy, we examined the issue of higher linguistic abilities lateralized to the right cerebral hemisphere (RH) in earlystage DAT. A modified version of an insertion task was administered to 14 patients with probable DAT, 8 right-hemisphere brain-damaged (RHD) patients, 8 left-hemisphere brain-damaged (LHD) patients, and 28 normal elderly (control, CTR) right-handed subjects. The task consisted of presenting the subjects with 53 well-formed sentences; in each a word or syntagm had to be inserted grammatically. Twenty-eight word/syntagm insertions required grammatical role reassignment of a lexical item in the stimulus sentence (shift, sensitive to RHD); 25 insertions implied only semantic reinterpretation of the target sentence (nonshift, sensitive to LHD). The three pathological groups were relatively and similarly impaired on standard aphasia assessment. The performances of the DAT patients, controlled for global cognitive verbal proficiency, verbal cognitive skills, and mood, were found to be significantly worse than the performances of the CTR group on both insertion subtests, whereas there were no significant differences between the DAT and RHD subjects on the shift items or between the DAT and LHD subjects on the nonshift items. Similarly, no differences were noted between the RHD and CTR nonshift scores, or between the LHD and CTR shift scores. On the other hand, the LHD group outscored the RHD group on the shift insertions. A comparison between the two insertion subtests revealed that only the RHD and DAT groups performed significantly worse on the shift than on the nonshift items. Results are consistent with other anecdotally reported RH-specific language-related disorders in early DAT and replicate previous findings of bihemispheric extralinguistic disturbances in these patients.

1H-MRS, MRI-based hippocampal volumetry, and 99mTc-HMPAO-SPECT in normal aging, age-associated memory impairment, and probable Alzheimer's disease.

To better understand how to differentiate the "in vivo" normal aging brain from pathological conditions, namely dementia of the Alzheimer type (DAT), by means of magnetic resonance imaging (MRI), single photon emission computerized tomography (SPECT), and proton magnetic resonance spectroscopy (1H-MRS), to show neuroanatomical, perfusional and neurochemical details, respectively. 1H-MRS, MRI-based hippocampal volumetry and 99mTc-HMPAO SPECT were performed in healthy older subjects as well as patients suffering from age-associated memory impairment (AAMI) and dementia of Alzheimer type (DAT). Eighteen subjects were selected from those referred to an outpatient clinic for diagnostic evaluation of cognitive impairment entered the study. Six patients fulfilled NINCDS-ADRDA diagnostic criteria for DAT, six subjects were affected by AAMI, and six cognitively healthy subjects, selected from among relatives of the patients, were defined as controls. The 1H-MRS and MRI studies were performed on a 1.5 Tesla NMR-imaging system equipped with a spectroscopy research package. SPECT scans were performed on a Gamma 11 computer system. 1H-MRS showed significantly lower N-acetylasparatate concentration in DAT and AAMI compared with controls. Conversely, mean inositol concentration was significantly higher in DAT than in controls, whereas AAMI subjects registered intermediate values. MRI measurements showed significantly reduced volumes of hippocampal formations in DAT and AAMI groups compared with controls. Finally, 99mTc-HMPAO SPECT showed a significant frontal, temporo-parietal, and occipital hypoperfusion in DAT patients only. These findings support the hypothesis of a continuum among the three conditions studied, or at least between AAMI and DAT, where AAMI seems to be an early, monosymptomatic stage of Alzheimer disease. Accepting this view, it would be questionable to maintain the term "age-associated memory impairment" as a discrete entity.

Peripheral antioxidant enzyme activities and selenium in elderly subjects and in dementia of Alzheimer's type—Place of the extracellular glutathione peroxidase

Defenses against free radical damage were determined in red blood cells and plasma from 40 patients with dementia of the Alzheimer-type (DAT) and 34 aged control subjects with normal cognitive function. No crude significant difference in erythrocyte copper-zinc superoxide dismutase (E-CuZnSOD), seleno-dependent glutathione peroxidase (E-GSH-Px), glutathione reductase (E-GSSG-RD) activities, and selenium (Se) concentration was found between DAT cases and control subjects. The peroxidation products evaluated in plasma by the thiobarbituric-reactive material (TBARS) were at the same level in the DAT group as compared to controls. In the DAT group, plasma GSH-Px (P-GSH-Px) activity and plasma Se (P-Se) were negatively correlated with age ( r = -0.58; p < 0.001 and r = -0.63; p < 0.001 respectively). Moreover, erythrocyte GSH-Px activity and Se were also negatively correlated with age ( r = -0.40; p < 0.01 and r = -0.46; p < 0.01, respectively). No significant correlation with age was observed in the controls. When controlling for age, a significant increase for P-GSH-Px activity and P-Se was observed in DAT patients as compared to controls. These significant differences mostly appeared in DAT subjects under 80 years. Some correlations were only observed in the DAT group such as P-GSH-Px and E-GSH-Px ( r = +0.68; p < 0.001); P-GSH-Px and E-Se ( r = +0.79; p < 0.001). Correlations between P-GSH-Px and P-Se, E-GSH-Px and P-Se, and P-Se with E-Se are greater in the DAT group ( r = +0.84; p < 0.001; r = +0.76; p < 0.001 and r = 0.75; p < 0.001) than in the control group ( r = 0.54, pI < 0.01; r = 0.43, p < 0.01 and r = +0.34, p < 0.05 respectively). The fact that first—a significant increase in P-GSHPx and P-Se, second-some modifications in the relationships between antioxidant parameters, and third-age-dependent decreases of glutathione-peroxidase activities and their cofactor, appeared only in the DAT group suggest that DAT is associated with an oxidative stress due to an imbalance between reactive oxygen species and the peripheral antioxidant opposing forces

Discriminant analysis of MRI measures as a method to determine the presence of dementia of the Alzheimer type

Multivariate discriminant analysis of brain volumes obtained from semiautomated magnetic resonance image (MRI) quantification was used in an attempt to identify demented patients very early in the course of the disease. Temporal and posterior frontal brain volumes were quantified from MRIs in a cross-sectional study of 31 male and female patients with dementia of the Alzheimer type (DAT) and 29 age- and sex-matched healthy comparison subjects. Mean scores on the Folstein Mini-Mental State Examination (MMS) were in the mild range for the DAT group (20 ± 6.6), but patients with moderate and severe dementia were also included (MMS range of entire DAT group = 4–28). Significant mean differences in frontal and temporal lobe brain volumes were found between the DAT group and the age- and sex-matched healthy comparison group, but the sensitivity of any single measure was limited to 87% with a specificity of 83%. Initial multivariate discriminant analysis revealed significant gender differences among the healthy subjects, but not the DAT patients. The large group size allowed for subsequent discriminant analyses to be performed by gender. All healthy subjects and DAT patients were correctly classified by gender-specific discriminant functions. The male discriminant function variables included brain volume, age, and temporal lobe measures. Inclusion of age in the male discriminant function accounted for age-related brain atrophy, a finding that may have emerged as a consequence of the broad age range of the male DAT population (50–81 years). The male discriminant function was also successfully applied to an independent group of mildly demented subjects that included patients for whom the diagnosis of dementia was uncertain but verified by follow-up clinical evaluations. Measures of temporal lobe brain matter and temporal lobe cerebrospinal fluid volumes were the significant discriminator variables for the women. Quantitative MRI and multivariate discriminant analysis showed promise in distinguishing the dementing process from healthy aging in a group of 60 subjects. Moreover, while not diagnostic of DAT, the approach appeared to offer additional information about the probability of a diagnosis being later confirmed in patients with very mild dementia for whom the clinical identification of DAT is uncertain.

Differentiation between Alzheimer's disease and multi‐infarct dementia: Spect vs MR imaging

AbstractSingle photon emission computed tomography (SPECT) and magnetic resonance (MR) imaging data were obtained in 11 patients with dementia of the Alzheimer type (DAT), 11 with multi‐infarct dementia (MID) and nine elderly, healthy controls. All patients with dementia tolerated a 15‐minute SPECT scan while six patients (27%) did not tolerate the MR examination due to the long acquisition times and/or claustrophobia. Blind qualitative rating of SPECT scans differentiated correctly between dementia and controls in 90% of cases (p &lt; 0.0001; positive predicted value of 91%) and between clinically defined DAT and MID in 77% of cases (p &lt; 0.01; positive predicted value of 80%). It correctly identified clinical group membership (control, DAT or MID) in 71% of cases (p &lt;0.001; predicted positive value of 94%) but failed to differentiate between DAT and MID (positive predicted value of 50%). Overall, MR imaging correctly identified clinical group membership in 61% of cases (p &lt; 0.01). Semiquantitative SPECT data demonstrated reduced regional cerebral blood flow (rCBF) in all regions of interest (ROI) except right frontal and right anterior parietal in both DAT and MID compared with controls (p &lt; 0.05). There was no statistically significant difference between DAT and MID subjects in rCBF in any ROI. Several correlations between rCBF and cognitive variables were found in the MID but not the DAT group. Though the sample in this study is small, our findings suggest that Tc‐99m HMPAO SPECT is a useful and practical tool in the assessment of patients with dementia. It enables the differential diagnosis of dementia and by using semiquantitative data it helps to establish the severity of disease.

Neurofibrillary tangles without cell loss in the lateral vestibular nucleus of patients with Alzheimer's disease

The lateral vestibular nucleus (LVN, nucleus of Deiters) was examined in the brains of four control subjects and four patients with dementia of the Alzheimer type (DAT). Neuronal counts on sections stained with silver and a polyclonal antibody to human choline acetyltransferase (ChAT) revealed an undiminished number of LVN neurons in patients with DAT. Numerous silver-stained neurofibrillary tangles (NFTs) were found in the DAT group, some also in the LVN of controls. These findings suggest that DAT affects LVN neurons, however without causing neuronal loss.