Medial temporal lobe atrophy and memory dysfunction as predictors for dementia in subjects with mild cognitive impairment

To determine whether the medial temporal lobe is atrophic in subjects with mild cognitive impairment, and whether atrophy of this structure is a better predictor of dementia than memory dysfunction. Forty-five noninstitutionalized subjects aged 65–85 years were randomly selected from a population based study to obtain a sample with Alzheimer’s disease (AD; n = 7), and a clinically nondemented sample (n = 38). Twenty of the latter subjects displayed some cognitive impairment and fulfilled CAMDEX criteria for “minimal dementia.” Coronal T1-weighted magnetic resonance imaging was used to visualize the medial temporal lobe. The volume of the parahippocampal gyrus and hippocampus was measured, and medial temporal lobe atrophy was assessed qualitatively. The memory subscore from the CAMCOG was used as a measure of memory functioning. The follow-up period was 3 years. Nine subjects who were diagnosed as being minimally demented at baseline met the criteria for AD during follow-up. At baseline the volume of the parahippocampal gyrus of these subjects was smaller than that of the other subjects with minimal dementia. The memory score was the best predictor of clinical outcome. All medial temporal lobe measures increased the accuracy of prediction compared with only the memory score, by reducing the number of false-negative classifications of dementia. Severe medial temporal lobe atrophy is present even in some subjects with mild cognitive impairment and is an indicator of subsequent AD. The absence of medial temporal lobe atrophy, however, does not exclude the development of dementia. In the majority of subjects memory impairment was a better predictor of dementia than atrophy of the medial temporal lobe. The combination of the two increased predictive accuracy. Nondemented subjects with severe atrophy of the medial temporal lobe could be enrolled in drug trials aimed at slowing the progression of AD. Received: 18 June 1998 Received in revised form: 28 September 1998Accepted: 4 November 1998     

Medial temporal lobe atrophy and memory deficits in elderly stroke patients

Medial temporal lobe atrophy (MTA) and its role in memory deficits have been studied extensively in patients with various dementias and non-degenerative neurologic diseases. In stroke patients MTA is a significant risk factor for dementia. However, its role in memory decline in non-demented stroke patients is not yet known. Our aim was to evaluate the relationship between MTA and cognitive functions in a large cohort of elderly patients, who underwent a comprehensive neuropsychologic examination and magnetic resonance imaging 3 months after an ischemic stroke. The study sample (n = 260) was divided into three groups according to the severity of MTA. After adjusting for age, volume of infarcts and cortical atrophy, we found that patients with moderate to severe MTA performed significantly worse in tests of learning, story recall, visual reproduction, block design and mental speed. In contrast, the groups did not differ in tests of digit span, flexibility, verbal fluency and conceptualization. Our conclusion is that in aged stroke patients, MTA is associated with poor performance in specific cognitive domains. The most vulnerable domains are memory and visuospatial functions, whereas verbal and executive functions seem to be unrelated to MTA.     

Weight loss in neurodegenerative disorders

Unintended weight loss frequently complicates the course of many neurodegenerative disorders and can contribute substantially to both morbidity and mortality. This will be illustrated here by reviewing the characteristics of unintended weight loss in the three major neurodegenerative disorders: Alzheimer’s disease, Parkinson’s disease and Huntington’s disease. A common denominator of weight loss in these neurodegenerative disorders is its typically complex pathophysiology. Timely recognition of the underlying pathophysiological process is of crucial importance, since a tailored treatment of weight loss can considerably improve the quality of life. This treatment is, primarily, comprised of a number of methods of increasing energy intake. Moreover, there are indications for defects in the systemic energy homeostasis and gastrointestinal function, which may also serve as therapeutic targets. However, the clinical merits of such interventions have yet to be demonstrated.     

Neuropsychology of memory and SPECT in the diagnosis and staging of dementia of Alzheimer type

We studied the role of neuropsychology and SPECT imaging in the diagnosis and staging of dementia of Alzheimer type (DAT) in 33 patients with mild disease and 30 matched controls. Working, episodic, semantic and remote memory were assessed. For diagnosis, it was determined by logistic regression analysis that one of the memory tests (delayed verbal recall of the Doors and People Test) could corectly classify subjects as DAT or controls in 97% of cases. For staging, stepwise regression analysis using five of the memory tests could predict 70% of the variance in Mini Mental State Examination (MMSE) scores. The measures most useful for staging were tests of immediate recall, and tests of working, semantic and autobiographical memory. In a separate experiment, SPECT imaging on 31 of the above 33 patients and 24 different controls was used to address the issue of diagnosis and staging.⁹⁹Tc-HMPAO SPECT scans were analysed quantitatively to obtain measures of regional cerebral blood flow (rCBF). Logistic regression analysis showed that three of the SPECT regions of interest (left posterior temporal, right high frontal and right posterior temporal) could correctly classify subjects in 75% of cases. Of note was the fact that 39% of the DAT patients had normal SPECT scans. SPECT data were of limited use in modelling disease severity; only 38% of the variance in MMSE scores could be predicted from SPECT data. In addition, we found that the pattern of rCBF in DAT was much more heterogeneous than previously described.     

Automated MRI analysis for identification of hippocampal atrophy in temporal lobe epilepsy

Background:   Hippocampal sclerosis is frequently associated with hippocampal atrophy (HA), which is often observed on routine magnetic resonance imaging (MRI) of patients with medial temporal lobe epilepsy (MTLE). Manual morphometry of the hippocampus is sensitive to detecting HA, but is time-consuming and prone to operator error. Automated MRI morphometry has the potential to provide rapid and accurate assistance in the clinical detection of HA.
Methods:   We performed a voxel-based morphometry analysis of 23 consecutive subjects with MTLE and 58 matched controls. Images from randomly selected 34 controls were used to create mean and standard deviation images of gray matter volume. Voxel-wise standardized Z-score hippocampal images from patients and the remaining 24 controls were cross-checked with receiver operating characteristic (ROC) curves to evaluate sensitivity versus one-specificity rate for a binary classifier (atrophied versus normal hippocampi).
Results:   The ipsilateral hippocampi of patients with MTLE displayed a significantly lower mean Z-score compared to the hippocampi of controls [F(2,67)  = 33.014, p < 0.001, Tukey HSD < 0.001]. A classifier using the hippocampal gray matter Z-scores to discriminate between atrophied and normal hippocampi yielded a fitted ROC = 97.3, traditionally considered an excellent discriminator, with a standard error of classification of 1.173 individuals if  100  patients and  100  controls are studied.
Conclusion:   Automatic morphometry can be potentially used as a clinical tool to assist the detection of HA in patients with MTLE. It can provide a quantifiable estimative of atrophy, which can aid in the decision about the presence of clinically relevant HA.     

The case described by Alois Alzheimer in 1911

In 1906, Alzheimer presented the first case of the disease which was later named Alzheimer’s disease by Kraeplin. While the publication on this case in 1907 is only a relatively short communication, Alzheimer published a very comprehensive paper in 1911 in which he discussed the concept of the disease in detail. This publication focusses on the report of a second patient suffering from Alzheimer’s disease, the case of Johann F. The detection of neurohistopathological sections from this patient found among archives at the Institute of Neuropathology of the University of Munich enabled us to reinvestigate this case using modern methods. Neurohistopathologically, the case of Johann F. is “plaque-only” Alzheimer’s disease. There is a controversy in the modern literature as to whether these “plaque-only” cases belong to the modern concept of Alzheimer’s disease. A careful analysis of all pros and contras in the literature led to the conclusion that plaque-only cases are also an integrative part of the modern Alzheimer disease concept. Received: 6 March 1998 / Accepted: 9 March 1998     

Evidence of memory impairment in asymptomatic individuals with hippocampal atrophy

Our objective was to investigate if MRI-determined hippocampal atrophy (HA) is associated with memory deficits independent of seizure frequency. We studied three groups of individuals: (1) 10 asymptomatic first-degree relatives of patients with familial mesial temporal lobe epilepsy (FMTLE), all of them with HA; (2) 14 patients with benign FMTLE, 9 with HA, and 5 with normal hippocampal volumes; and (3) 16 patients with refractory FMTLE, all but one with HA. HA was associated with lower scores on general memory (P=0.015), verbal memory (P=0.020), and delayed recall (P=0.028), even in those with no or few seizures in life. General linear model analyses showed that the interaction between seizure outcome and HA was associated with worse verbal memory (P=0.029), visual memory (P=0.022), and delayed recall (P=0.039) as compared with each of these factors independently. Our findings suggest that seizures and HA are independently associated with memory impairment.     

Cerebral atrophy in Parkinson's disease—Represented in CT

Summary To clarify the importance of brain atrophy in relation to the symptoms of Parkinson's disease, 173 patients were examined by computed tomography (CT). In 51.4% of the CT findings, brain atrophy was considered to be pathological. Statistically significant relations of age and sex were found with regard to the extent and localization of brain atrophy. Cortical atrophy also showed a significant dependence on duration of disease. Linear measurements at the lateral ventricles and the third ventricle lead us to assume that brain atrophy in Parkinson's patients is more prevalent than in normal patients within the scope of age involution.     

Progression of brain atrophy in multiple system atrophy

In this study, we aimed to determine the progression of brain atrophy in the parkinson variant of multiple system atrophy (MSA-P). Voxel-based morphometry was applied to two consecutive high resolution MR images of 14 patients with probable MSA-P in comparison to 14 patients with Parkinson's disease (PD). The time interval between baseline and follow-up investigations (1.0 +/- 0.5 SD years in MSAP and 1.4 +/- 0.6 SD years in PD patients) was introduced as covariate in the statistical analysis. Additionally, correlation analyses were performed between the progression maps and clinical data. We observed marked progression of brain atrophy in the MSA-P cohort, the regions including striatum, mesencephalon, thalamus and cerebellum, but also cortical regions such as the primary sensorimotor cortex, supplementary motor area, lateral premotor cortex, medial frontal gyrus, middle frontal gyrus, orbito-frontal cortex,insula, posterior parietal cortex and hippocampus. Short disease duration was correlated with progression of atrophy in the striatum whereas longer disease duration was correlated with increasing atrophy in the cortical areas and cerebellar hemispheres. The UPDRS-III score was not significantly correlated with any brain region. Our data suggest that cortical atrophy is prominent in MSA-P and early degeneration of the basal ganglia drives late onset cortical atrophy.     

Characterization of tau pathologies in gray and white matter of Guam parkinsonism-dementia complex

Guam parkinsonism-dementia complex (PDC) is a neurodegenerative tauopathy in ethnic Chamorro residents of the Mariana Islands that manifests clinically with parkinsonism as well as dementia and is characterized neuropathologically by prominent cortical neuron loss in association with extensive telencephalic neurofibrillary tau pathology. To further characterize cortical gray and white matter tau, alpha-synuclein and lipid peroxidation pathologies in Guam PDC, we examined the brains of 17 Chamorro PDC and control subjects using biochemical and immunohistological techniques. We observed insoluble tau pathology in both gray and white matter of PDC and Guam control cases, with frontal and temporal lobes being most severely affected. Using phosphorylation dependent anti-tau antibodies, abundant tau inclusions were detected by immunohistochemistry in both neuronal and glial cells of the neocortex, while less alpha-synuclein pathology was observed in more limited brain regions. Further, in sharp contrast to Alzheimer’s disease (AD), levels of the lipid peroxidation product 8, 12–iso-iPF_2α-VI isoprostane were not elevated in Guam PDC brains relative to controls. Thus, although the tau pathologies of Guam PDC share similarities with AD, the composite Guam PDC neuropathology profile of tau, alpha-synuclein and 8, 12-iso-iPF_2α-VI isoprostane reported here more closely resembles that seen in other tauopathies including frontotemporal dementias (FTDs), which may imply that Guam PDC and FTD tauopathies share underlying mechanisms of neurodegeneration.     

Quantitative EEG and medial temporal lobe atrophy in Alzheimer's dementia: Preliminary study

Backgrounds:

The electroencephalogram (EEG) abnormalities in Alzheimer''s disease (AD) have been widely reported, and medial temporal lobe atrophy (MTLA) is one of the hallmarks in early stage of AD. We aimed to assess the relationship between EEG abnormalities and MTLA and its clinical validity.

Materials and Methods:

A total of 18 patients with AD were recruited (the mean age: 77.83 years). Baseline EEGs were analyzed with quantitative spectral analysis. MTLA was assessed by a T1-axial visual rating scale (VRS).

Results:

In relative power spectrum analysis according to the right MTLA severity, the power of theta waves in C4, T4, F4, F8, and T5 increased significantly and the power of beta waves in T6, C4, T4, F8, T5, P3, T3, and F7 decreased significantly in severe atrophy group. In relative power spectrum analysis according to the left MTLA severity, the power of theta waves in T3 increased significantly and that of beta waves in P4, T6, C4, F4, F8, T5, P3, C3, T3, F3, and F7 decreased significantly in severe atrophy group.

Conclusion:

The severe MTLA group, regardless of laterality, showed more severe quantitative EEG alterations. These results suggest that quantitative EEG abnormalities are correlated with the MTLA, which may play an important role in AD process.     

Correlation between triplet repeat expansion and computed tomography measures of caudate nuclei atrophy in Huntington’s disease

Huntington’s disease (HD) is an autosomal dominant, progressive disorder characterized by choreic movements, cognitive decline, and psychiatric manifestations. Eleven patients with HD were retrospectively selected from a larger group of 42 patients based on the similar, early onset of the disease (between 21 and 30 years) and the same duration of HD at the moment of computed tomography (CT) examination (5 years). A significant correlation between the number of CAG trinucleotides and the bicaudate index or the frontal horn index, two indices of caudate atrophy, was found in this group of patients. Our results, although in a small number of patients, suggest that the striatal degeneration, assessed by CT measures, is primarily regulated by the size of expanded CAG repeats. Received: 6 November 1998 Received in revised form: 10 May 1999 Accepted: 19 June 1999     

Neocortical temporal FDG-PET hypometabolism correlates with temporal lobe atrophy in hippocampal sclerosis associated with microscopic cortical dysplasia

PURPOSE: Medically intractable temporal lobe epilepsy (TLE) due to hippocampal sclerosis (HS), with or without cortical dysplasia (CD), is associated with atrophy of the hippocampal formation and regional fluorodeoxyglucose positron-emission tomography (FDG-PET) hypometabolism. The relation between areas of functional and structural abnormalities is not well understood. We investigate the relation between FDG-PET metabolism and temporal lobe (TL) and hippocampal atrophy in patients with histologically proven isolated HS and HS associated with CD. METHODS: Twenty-three patients underwent en bloc resection of the mesial and anterolateral neocortical structures. Ten patients were diagnosed with isolated HS; 13 patients had associated microscopic CD. Temporal lobe volumes (TLVs) and hippocampal volumes were measured. Magnetic resonance imaging (MRI) and PET were co-registered, and regions of interest (ROIs) determined as gray matter of the mesial, lateral, and anterior temporal lobe. RESULTS: All patients (HS with or without CD) had significant ipsilateral PET hypometabolism in all three regions studied (p < 0.0001). In patients with isolated HS, the most prominent hypometabolism was in the anterior and mesial temporal lobe, whereas in dual pathology, it was in the lateral temporal lobe. TLVs and hippocampal volumes were significantly smaller on the epileptogenic side (p < 0.05). The PET asymmetries ipsilateral/contralateral to the epileptogenic zone and TLV asymmetries correlated significantly for the anterior and lateral temporal lobes (p < 0.05) in the HS+CD group, but not in the isolated HS group. Mesial temporal hypometabolism was not significantly different between the two groups. CONCLUSIONS: Temporal neocortical microscopic CD with concurrent HS is associated with more prominent lateral temporal metabolic dysfunction compared with isolated HS in TL atrophy. Further studies are needed to confirm these findings and correlate the PET hypometabolic patterns with outcome data in patients operated on for HS with or without CD.     

Early diagnosis of dementia: neuropsychology

Neuropsychology contributes greatly to the diagnosis of dementia. Cognitive deficits can be detected several years before the clinical diagnosis of dementia. The neuropsychological profile may indicate the underlying neuropathology. Neuropsychological assessment at an early stage of dementia has two goals: (a) to determine a memory disorder, not always associated with a memory complaint, and (b) to characterize the memory disorder in light of the cognitive neuropsychology and to assess other cognitive (and noncognitive) functions toward integrating the memory disorder in a syndrome. We review the global tools, the memory tests that describe the memory profile and indicate the underlying pathology, the assessment of other cognitive functions, and the neuropsychological patterns of typical Alzheimer’s disease, frontotemporal dementia, primary progressive aphasia, semantic dementia, Lewy body dementia, subcortical dementia, and vascular dementia. These patterns must be interpreted in the light of the history, rate of progression, imaging results, and nature of existing behavioral disturbances. Moreover, there may be overlap between two or more pathologies, which complicates the diagnostic process. Follow-up of patients is necessary to improve diagnostic accuracy. Received: 20 July 1998 Accepted: 23 July 1998     

Coexistence of Alzheimer-type neuropathology in Creutzfeldt-Jakob disease

Creutzfeldt-Jakob disease (CJD) and Alzheimer’s disease (AD) share clinical, neuropathological, and pathogenetic features. To investigate eventual mutual influences, we screened prominently affected neocortex from 110 neuropathologically proven CJD patients for Alzheimer-type pathology with anti-β/A4, Bielschowsky and anti-tau (immuno)stains. The neuropathological classification of Alzheimer-type pathology was made according to the CERAD criteria. Results were controlled by comparison with Alzheimer-type changes in sections from the same cortical areas in 110 sex- and age-matched non-demented control patients. For comparison, the control patients were also classified according to the CERAD neuropathology criteria as if they had been demented. Alzheimer-type tissue changes as in definite and probable CERAD AD occur in 10.9% of the CJD patients and 19.1% of control patients (P = 0.11). The median age of CJD and control patients with CERAD AD is 72 and 68 years, respectively, which differs significantly from the median ages of 64 and 63 years, respectively, in the non-AD/CJD and non-AD control patients. Since CERAD criteria include “presence of other neuropathological lesions likely to cause dementia”, an AD diagnosis in CJD patients (all of whom are demented) is solely based on densities of neuritic plaques. Similar Alzheimer-type changes in even higher frequency, however, are also present in elderly non-demented controls. Thus, the coexistence of Alzheimer-type pathology in CJD most likely represents an age-related change. Deposits of prion protein (PrP) frequently accumulate at the periphery of β/A4 plaques. The presence of β/A4 amyloid in the brain may influence PrP morphogenesis. Received: 18 November 1997 / Revised, accepted: 11 February 1998     

The course of brain atrophy in Parkinson's disease

Summary In 110 parkinsonian patients (53 men, 57 women) aged 38–81 years, computer-tomographic follow-up investigations were done to assess the development of brain atrophy. The control examinations were done after an average of 28 months. At that time an increase in brain atrophic changes of different localization could be observed in 23% of the patients. In addition, it could be demonstrated that the increase in pathologic CT findings is to be observed especially in patients with higher age, a more marked impairment in psycho-organic capacity, more pronounced handicaps in the fine-motorial performances at the beginning of the study. From the neuroradiological point of view, patients with more marked pathologic CT findings upon the first examination, be these ventricular enlargement and/or cortical atrophy, more often showed a progression of brain atrophy.     

Minicolumn thinning in temporal lobe association cortex but not primary auditory cortex in normal human ageing

The cerebral cortex undergoes changes during normal ageing with increasing effect on cognition. Disruption of minicolumnar organization of neurons is found with increased cognitive impairment in primates. We measured the minicolumn spacing and organization of cells in Heschl’s gyrus (primary auditory cortex, A1), the Planum Temporale (Tpt, BA22), and middle temporal gyrus (MTG, BA21) of 17 normally aged human adults. Age-associated minicolumn thinning was found in temporal lobe association cortex (Tpt and MTG) but not primary auditory cortex (HG). Minicolumn thinning was also associated with greater plaque load, although this effect was present in all areas. The regional variability of age-associated minicolumn thinning reflects the regionally selective progression of tangle pathology in Alzheimer’s Disease (AD). The generalized effect of plaque load persists when controlling for age. Therefore plaque load combines with age to increase minicolumn thinning, which may reflect increasing risk of AD. Since old age is the greatest risk factor for dementia, the transition to dementia may involve an extension of normal ageing processes.