Alzheimer's disease and senile dementia of Alzheimer type. A comparative study

Alzheimer's disease and epilepsy: An increasingly recognized comorbidity

Both Alzheimer's disease (AD) and epilepsy are common chronic diseases in older people. Seizures and epileptiform discharges are very prevalent in AD and can occur since any stage of AD. Increasing evidence indicates that AD and epilepsy may be comorbid. Several factors may be related to the underlying mechanism of the comorbidity. Identifying seizures in patients with AD is a challenge because seizures are often clinically non-motor and may overlap with some AD symptoms. Not only seizures but also epileptiform discharges may exacerbate the cognitive decline in AD patients, highlighting the importance of early recognition and treatment. This review provides a comprehensive overview of seizures in AD from multiple aspects to provide more insight.

Neuronal Network Excitability in Alzheimer's Disease: The Puzzle of Similar versus Divergent Roles of Amyloid β and Tau

Alzheimer’s disease (AD) is the most frequent neurodegenerative disorder that commonly causes dementia in the elderly. Recent evidence indicates that network abnormalities, including hypersynchrony, altered oscillatory rhythmic activity, interneuron dysfunction, and synaptic depression, may be key mediators of cognitive decline in AD. In this review, we discuss characteristics of neuronal network excitability in AD, and the role of Aβ and tau in the induction of network hyperexcitability. Many patients harboring genetic mutations that lead to increased Aβ production suffer from seizures and epilepsy before the development of plaques. Similarly, pathologic accumulation of hyperphosphorylated tau has been associated with hyperexcitability in the hippocampus. We present common and divergent roles of tau and Aβ on neuronal hyperexcitability in AD, and hypotheses that could serve as a template for future experiments.

The overlap between epilepsy and Alzheimer's disease and the consequences for treatment

Introduction: Alzheimer's disease may be associated with both clinical and subclinical epileptic seizure activity. Once regarded as an epiphenomenon, epileptiform activity may, in fact, be an integral part of the Alzheimer's phenotype, and may be not only a symptomatic therapeutic target but also a possible mechanism to retard or prevent disease progression. Areas covered: The authors review clinical research articles with a focus on the semiology, epidemiology, and treatment of seizures in Alzheimer's disease, and also look at some experimental animal model studies which have informed clinical thinking on seizure aetiopathogenesis. The evidence base for treatment decisions is sparse. A brief overview of the clinical assessment of Alzheimer's disease patients considering relevant differential diagnoses and diagnostic pitfalls is presented. Expert opinion: Studies of epileptic seizures in Alzheimer's disease have become more frequent over the last 5-10 years. Understanding of seizure semiology, epidemiology, and possible pathogenesis has increased. However, the optimal management of seizures in this context remains unknown, largely due to the paucity of studies sufficient to examine this question. Clearly, such studies will be required, not only to inform clinicians about symptomatic control of seizures in Alzheimer's disease but also to investigate whether this might impact on disease progression.

Seizure in Alzheimer's Disease: An Underestimated Phenomenon

Alzheimer's disease (AD) is considered as a potential risk factor for the development of seizure due to neurodegeneration and imbalance between stimulatory and inhibitory circuits in the brain. Seizure could occur in any point during the course of AD, and its presentation varies from fluctuation in cognitive domains to more typical seizures. The clinical diagnosis of seizure in patients with dementia may be challenging due to difficulty in history taking and clinical assessment. No paraclinic methods other than electroencephalogram (EEG) could provide arguments for the diagnosis of AD-related seizures (neither imaging modalities nor cerebrospinal fluid biomarkers). Standard 30-minute EEG may not be sufficiently sensitive to detect epileptiform discharges. In the present study, we aim to review different aspects of seizure in AD, including seizure prevalence, risk factors, underlying mechanisms, electroencephalographic findings, clinical presentations, impact of seizures on AD, and treatment options.

Potential Similarities in Temporal Lobe Epilepsy and Alzheimer’s Disease: From Clinic to Pathology

Alzheimer’s disease (AD) is clinically characterized by insidious onset of memory and cognitive impairments, which are also presented in patients with temporal lobe epilepsy (TLE). Many studies have shown that seizures occur in some patients with AD, and AD is a risk factor for epilepsy, mainly complex partial and secondary generalized seizure. Here, we focus on the relationship between TLE and AD in clinical and pathological aspects, as they are having similar comorbidities and mechanisms. In this study, we first reviewed the clinical observations that showed concomitant AD and TLE. Then, we picked up common genetic and pathological changes in both the diseases from neurobiological researches. Although both the diseases have delicate differences in many aspects, their common characteristics intrigue more detailed research to be done by newer technology.

Seizures in Alzheimer's disease

Alzheimer's disease (AD) increases the risk for late-onset seizures and neuronal network abnormalities. An elevated co-occurrence of AD and seizures has been established in the more prevalent sporadic form of AD. Recent evidence suggests that nonconvulsive network abnormalities, including seizures and other electroencephalographic abnormalities, may be more commonly found in patients than previously thought. Patients with familial AD are at an even greater risk for seizures, which have been found in patients with mutations in PSEN1, PSEN2, or APP, as well as with APP duplication. This review also provides an overview of seizure and electroencephalography studies in AD mouse models. The amyloid-β (Aβ) peptide has been identified as a possible link between AD and seizures, and while Aβ is known to affect neuronal activity, the full-length amyloid precursor protein (APP) and other APP cleavage products may be important for the development and maintenance of cortical network hyperexcitability. Nonconvulsive epileptiform activity, such as seizures or network abnormalities that are shorter in duration but may occur with higher frequency, may contribute to cognitive impairments characteristic of AD, such as amnestic wandering. Finally, the review discusses recent studies using antiepileptic drugs to rescue cognitive deficits in AD mouse models and human patients. Understanding the mechanistic link between epileptiform activity and AD is a research area of growing interest. Further understanding of the connection between neuronal hyperexcitability and Alzheimer's as well as the potential role of epileptiform activity in the progression of AD will be beneficial for improving treatment strategies.

Seizures in Alzheimer disease: clinical and epidemiological data

Alzheimer disease (AD) and epilepsy are disorders commonly seen in the elderly. Many studies have shown that patients with AD are at increased risk for developing seizures and epilepsy. Whereas, patients with specific types of epilepsy, such as temporal lobe epilepsy (TLE), experience some degree of cognitive dysfunction, questions have been raised as to whether these disorders share some underlying pathophysiologic mechanisms or whether one is an epiphenomenon of the other. In this report, we review some of the available clinical and epidemiologic literature on various aspects of the topic of seizures in AD, including seizure rates and types, risk factors for seizures, electroencephalographic findings, treatment options, limitations, and methodological issues. Overall, multiple aspects of the literature on seizures and epilepsy in AD, including diagnosis, risk factors, the role of EEG in diagnosis, and the response to treatment are not clear and suffer from many methodological limitations and gaps.

Evolution of the diagnostic criteria for degenerative and cognitive disorders

PURPOSE OF REVIEW

This review describes the evolution of the clinical criteria for Alzheimer's disease over the past 25 years, with special emphasis on those recently published that have incorporated the use of biomarkers.

RECENT FINDINGS

One of the most important advances in the knowledge of Alzheimer's disease was the development of cerebrospinal fluid, PET and MRI biomarkers. These have shown that the Alzheimer's disease is present in cognitively normal individuals, suggesting that there is a long incubation process that precedes the onset of the symptoms. Although there are diagnostic criteria for Alzheimer's disease, the National Institute on Aging and the Alzheimer's Association has proposed a set of diagnostic criteria oriented to provide a unified vision of the pathological process from preclinical, to mild cognitive impairment, and to full-blown dementia. These new criteria take advantage of different biomarkers to support the clinical diagnosis of the different stages of the disease.

SUMMARY

The new guidelines provide a definition of the dementia syndrome and core diagnostic features to be used in research and clinical practice, although they caution about the use of biomarkers, since they still require validation, and the longitudinal interaction and dynamics of these biomarkers in relationship to the manifestation of the symptoms are not fully understood.

Seizures and epilepsy in Alzheimer's disease

Many studies have shown that patients with Alzheimer's disease (AD) are at increased risk for developing seizures and epilepsy. However, reported prevalence and incidence of seizures and relationship of seizures to disease measures such as severity, outcome, and progression vary widely between studies. We performed a literature review of the available clinical and epidemiological data on the topic of seizures in patients with AD. We review seizure rates and types, risk factors for seizures, electroencephalogram (EEG) studies, and treatment responses. Finally, we consider limitations and methodological issues. There is considerable variability in the reported prevalence and incidence of seizures in patients with AD-with reported lifetime prevalence rates of 1.5-64%. More recent, prospective, and larger studies in general report lower rates. Some, but not all, studies have noted increased seizure risk with increasing dementia severity or with younger age of AD onset. Generalized convulsive seizures are the most commonly reported type, but often historical information is the only basis used to determine seizure type and the manifestation of seizures may be difficult to distinguish from other behaviors common in demented patients. EEG has infrequently been performed and reported. Data on treatment of seizures in AD are extremely limited. Similarly, the relationship between seizures and cognitive impairment in AD is unclear. We conclude that the literature on seizures and epilepsy in AD, including diagnosis, risk factors, and response to treatment suffers from methodological limitations and gaps.

Presenilin-1 mutation Alzheimer's disease: a genetic epilepsy syndrome?

Mutations in the presenilin-1 gene (PSEN1) on chromosome 14 are the most common cause of autosomal dominant Alzheimer's disease (AD), with around 180 mutations described to date. PSEN1 AD has a broad clinical phenotype, encompassing not only dementia but a variety of other neurological features which may include epileptic seizures. Around 20% of recorded PSEN1 mutations have been reported to be associated with epileptic seizures, sometimes occurring as an early feature of disease, sometimes late. The epilepsy-associated PSEN1 mutations are spread throughout the PSEN1 gene. This frequency of seizure-associated PSEN1 mutations may be an underestimate, as epileptic seizures may not be recognized as such in the context of a dementing disorder, perhaps being labeled as "confusion" or delirious episodes. A high index of clinical suspicion for epileptic seizures in PSEN1 AD is therefore appropriate. The neuropathological substrates of PSEN1 AD-related seizures remain to be determined, as few such cases have undergone detailed neuropathological examination. Nevertheless, PSEN1 AD should now be recognized, using the new International League Against Epilepsy nomenclature, as a genetic epilepsy syndrome.

Seizures in Alzheimer disease: who, when, and how common?

BACKGROUND

Transient symptoms in Alzheimer disease (AD) are frequent and include seizures, syncope, and episodes of inattention or confusion. The incidence of seizures in AD and predictors of which patients with AD might be more predisposed to them is based primarily on retrospective studies and is not well established.

OBJECTIVE

To determine the incidence and predictors of new-onset unprovoked seizures.

DESIGN

Prospective cohort study.

SETTING

Three academic centers. Patients Four hundred fifty-three patients with probable AD observed prospectively from mild disease stages since 1992. Main Outcome Measure Informant interviews every 6 months included questions about whether the patient had a seizure (convulsion, fainting, or "funny" spell) and whether diagnosis or treatment for epilepsy or seizure was made. Two epileptologists independently retrospectively reviewed all available medical records for 52 patients with positive responses to either of these questions, and using a specific checklist form, events were diagnosed as to whether they were unprovoked seizures (intrarater concordance, kappa = 0.67). Diagnosis of unprovoked seizures constituted the event in survival analyses. Potential predictors included sex, age, race/ethnicity, educational achievement, duration of illness, baseline cognition and function, depression, medical comorbidities, and time-dependent use of cholinesterase inhibitors and neuroleptic agents, apolipoprotein E genotype, and previous electroencephalographic findings.

RESULTS

Over the course of 3518 visit-assessments (per patient: mean, 7.8; maximum, 27), 7 patients (1.5%) developed seizures. Younger age was associated with higher risk (hazard ratio, 1.23; 95% confidence interval, 1.08-1.41; P = .003 for each additional year of age) of seizure incidence. No other predictor was significant. The overall incidence of seizures was low (418 per 100 000 person-years of observation) although significantly higher than expected for idiopathic unprovoked seizures in similar age ranges of the general population (hazard ratio, 8.06; 95% confidence interval, 3.23-16.61).

CONCLUSIONS

Unprovoked seizures are uncommon in AD, but they do occur more frequently than in the general population. Younger age is a risk factor for seizures in AD.

Epileptic seizures in AD patients

Epileptic seizures have long been recognised as a complication of the clinical syndrome of Alzheimer's disease, particularly in advanced disease, but have hitherto been viewed essentially as epiphenomena of the neurodegenerative process. Progress with animal models of Alzheimer's disease has suggested that this view may be incorrect, and that seizures may be a reflection of pathophysiological processes similar to or overlapping with those responsible for cognitive decline. This overlap between neuropsychological and neurophysiological changes suggests that seizures in Alzheimer's disease may be a valid therapeutic target, over and above symptomatic treatment. This article reviews data on the prevalence of seizures in Alzheimer's disease, seizure types, pathophysiology and treatment. Seizure prevalence increases with disease duration, but early-onset disease is associated with a greater risk of seizures, in part related to the frequency of presenilin-1 gene mutations in early-onset disease. Seizures are mostly of partial origin, with both complex partial and secondary generalised seizures. Seizure pathophysiology may relate to increased amyloid beta-peptide production, structural alterations in neurones related to cytoskeletal dysfunction, cerebrovascular changes, neurotransmitter dysfunction or combinations thereof. Through modification of these pathophysiological pathways, there may be possible roles for anti-epileptic drugs such as sodium valproate and lacosamide in the treatment of Alzheimer's disease. In summary, epileptic seizures are part of the AD phenotype, and merit further investigation.

Reappraisal of a consecutive autopsy series of patients with primary degenerative dementia: Lewy-related pathology

Dementia with Lewy bodies (DLB) is a common but underdiagnosed dementing disorder. Its criteria were defined in 1996, and revised in 2005. DLB is characterised neuropathologically by widely distributed cortical Lewy bodies (LBs), usually associated with Alzheimer-type pathology. We have re-evaluated the neuropathology of 55 autopsied patients with clinically diagnosed primary degenerative dementia to determine the frequency of DLB in this cohort, which was originally examined when neither the entity of DLB nor its diagnostic criteria had been defined. We also evaluated how discovery of a new entity affects previous diagnoses. Of the 55 brains, 16 (29%) contained LBs. All 16 originally had a neuropathological diagnosis of Alzheimer's disease (AD). 11 (20%) fulfilled the neuropathological criteria for DLB. Three patients had AD with LBs in the brain stem only, and two patients had LBs in the limbic cortex only. Because the criteria and reliable markers for DLB were not available at the time of the autopsies, the diagnosis of DLB had not been possible. The common co-occurrence of AD-type pathology in DLB makes the clinical diagnosis of DLB problematic even today. This study also raises the question of the relative significances of Lewy-related and AD-type pathologies to the development of dementia.

Seizures in elderly patients with dementia: epidemiology and management

Epileptic seizures occur in patients with dementia at a higher prevalence than among healthy elderly individuals. The incidence of seizures among patients with dementia varies with the aetiology of the dementing illness. In patients with Alzheimer's disease (the most common form of dementia), approximately 10-22% have at least one unprovoked seizure. Seizures usually occur in later stages of Alzheimer's disease, on average, > or =6 years into the course of the disease. Seizures in Alzheimer's disease are more likely to occur with early-onset disease, particularly if there is a familial presenilin I mutation. The incidence of seizures in other dementing diseases is less clear. There are special considerations regarding the management of seizures in the elderly with dementia. First, the presence of cognitive impairment may impede an accurate diagnosis of seizures. Clinicians may also mistake seizure manifestations for symptoms of the underlying dementia. Second, since most dementia patients are elderly, there are pharmacokinetic changes with aging that affect the use of antiepileptic drugs. Third, antiepileptic drugs have potential cognitive adverse effects that may worsen dementia. Although few studies are available, extrapolations from research in young people and elderly patients without dementia provide several recommendations for the management of seizures in patients with dementia: exclude symptomatic causes of seizures before committing to antiepileptic drug therapy; treat after a first seizure if there is evidence of focal neurological involvement or a risk of recurrent seizures; use antiepileptic drugs with minimal cognitive adverse effects, such as carbamazepine, valproic acid, gabapentin and lamotrigine; and use the lowest possible dosage and monitor antiepileptic drug levels, where possible.

EEG power spectrum differences in early and late onset forms of Alzheimer's disease

OBJECTIVE

To evaluate the relationship between some EEG spectral parameters and age of onset of Alzheimer's disease (AD).

METHODS

A study on the wakefulness EEG, recorded during eyes closed and open, was carried out on 150 AD patients (NINCDS-ADRDA criteria). Fifty-two normal subjects served as controls.

RESULTS

A significant prevalence of an EEG spectrum characterised by lack of a dominant peak in the 6.5-12 Hz band was found in early AD (EAD). Age of onset correlated inversely with the 1-6.5 Hz relative powers and positively with 6.5-12 Hz relative powers. A similar correlation was also found when a subgroup of mild initial AD was selected. Moreover, evidence of EEG changes peculiar to early onset AD emerged when 3 subgroups (with age of onset < or =60, range 61-69 and > or =70 years) were compared.

CONCLUSION

Irrespective of the severity of disease, this study provides evidence of specific changes of wakeful EEG in patients affected by early-onset AD.

Episodes of lucidity in people with severe dementia as narrated by formal carers

Twenty formal carers employed in three nursing homes narrated 92 episodes of lucidity (ELs) in people with severe dementia. Sixty-two episodes concerned speech, nine concerned actions and 21 episodes concerned both speech and actions. Most ELs were said to occur spontaneously when the patients were acting closely together with a carer who did not make demands on them and regarded them as valuable human beings whose behaviour was a meaningful expression of their experiences. The narrations showed characteristics that indicated trustworthiness and the episodes described in three separate nursing homes were very similar and resembled descriptions given in previous research reports as well as in relatives' reports. Further research seems necessary and the assumption that severe dementia implies the destruction of the self or personhood must be questioned.

Neuromotor changes in Alzheimer's disease: implications for patient care

As a result of the neuropathologic process of Alzheimer's disease (AD), significant changes occur in neuromotor function (e.g., paratonia and compulsive grasping). These changes become manifest in the moderately severe stage of AD, when patients begin to require ongoing assistance with activities of daily life (ADL), and they are prominent in the severe stage of AD, when patients are continuously dependent on a caregiver. Patients in these stages often display behavioral disturbances during care activities. These disturbing behaviors result not only from cognitive impairment, but also from a patient's physical inability to cooperate with the caregiver. When care management strategies take into account the characteristic physical restrictions resulting from the neuromotor changes that accompany advanced AD, the caregiving process may be significantly facilitated.

Electroencephalographic abnormalities in patients with presenile dementia of the Alzheimer type: quantitative analysis at rest and during photic stimulation

In the present study, quantitative electroencephalographic (EEG) analysis was performed at rest and during photic stimulation (5, 10, and 15 Hz) in nine patients with presenile dementia of the Alzheimer type (AD; mean age at onset, 55 years) and nine sex- and age-matched control subjects. Compared with the normal controls, the AD patients had a significantly lower alpha-2 and beta band power in the resting EEG as well as a significant increase in delta and theta band power. EEG analysis during the photic stimulation demonstrated that the AD patients had a significantly lower EEG power during photic stimulation for the alpha (9.8-10.2 Hz) and beta bands (14.8-15.2 Hz) corresponding to photic stimulation at 10 Hz and 15 Hz, respectively. In addition, when we examined EEG changes from rest to the stimulus condition, the AD patients were found to show significantly smaller changes in EEG power mainly over the posterior regions, irrespective of the stimulus frequency. These findings provide evidence that AD patients have EEG abnormalities in both non-stimulus and stimulus conditions, and suggest diminished EEG reactivity to photic stimulation.

Brain electrical activity (quantitative EEG and bit-mapping neurocognitive CNV components), psychometrics and clinical findings in presenile subjects with initial mild cognitive decline or probable Alzheimer-type dementia

Clinical, neuropsychological and neuropsychophysiological data (Q-EEG, ERPs and CNV/RT activity) were obtained from 24 patients who had more or less severe presenile primary cognitive decline without depression, and compared with similar data from 10 age-matched healthy volunteers (mean age, 59.4 years). All of the patients (15 M and 9 F; mean age 59.6 years) were selected according to the DSM III-R, ICD-10 and NINCDS-ADRDA criteria and underwent CT and MRI scanning, in addition to a standard clinical examination, a battery of psychometric tests, spectral EEG, and bit-mapped CNV complex and RT to S2 analyses. Twelve of the 24 patients presented an initial presenile idiopathic cognitive decline (PICD) but did not wholly fulfil the clinical and neuropsychological criteria for primary dementia or for a diagnosis of probable AD; the remaining 12 patients showed characteristic clinical signs and symptoms of a very probable early stage of presenile Alzheimer-type dementia (PAD). ANOVA, correlational and discriminant analyses of the neuropsychological test scores, and the neurophysiological and RT to S2 data revealed 22 highest-ranked between-group discriminant factors (all with a significance level of p < 0.01). The conclusive discriminant analysis retained 13 of these factors as final canonical functions, and these showed a 97% grouping accuracy (33 of the 34 subjects examined); the same percentage of correct classifications was also achieved using only the 15 best indicators in the group of CNV/RT findings. Using both of these sets of highest-ranked discriminators, all of the normal subjects and all of the PAD patients were correctly classified; only 1 PICD patient was misclassified as normal when the first group of 13 factors was used, and another PICD patient was misclassified as PAD using the second group of 15 factors. Our findings suggest that, providing they are correctly performed and interpreted, these non-invasive techniques may be an important tool for identifying incipient stages of presenile Alzheimer-type dementia.

A large pedigree with early-onset Alzheimer's disease: clinical, neuropathologic, and genetic characterization

We present clinical, neuropsychological, and neuropathologic data on a large pedigree including 34 subjects with early-onset progressive dementia. The mean (+/- SD) age at onset was 46 +/- 3.5 years and the mean age at death 52.6 +/- 5.7 years. Twelve patients were clinically diagnosed as having probable Alzheimer's disease (AD) according to the NINCDS-ADRDA criteria. Neuropsychological evaluation, performed at a moderate stage of the disease, was available in six subjects and showed a classic pattern of cognitive deficit. Myoclonus and extrapyramidal signs were common, and seizures were present in all affected subjects. There were neuropathologic changes typical of AD in two brains. A significant lod score of 5.48 was observed at a recombination fraction of theta = 0.0 with the genetic marker D14S43, thereby establishing that the responsible gene was located on chromosome 14q24.3. These results suggest that epilepsy could represent a particular feature in AD families linked to chromosome 14q.

Seizures in Alzheimer's disease: clinicopathologic study

New-onset epileptic seizures occur in patients with Alzheimer's disease (AD), but the nature and underlying reasons for these seizures are unclear. We identified new-onset, nonsymptomatic seizures in 77 (17%) of 446 patients with uncomplicated, definite AD on autopsy. Among these seizure patients, 69 had generalized tonic-clonic seizures, and 55 had less than three total seizures. The seizure patients had a younger age of dementia onset than did the remaining AD patients; however, at seizure onset, they averaged 6.8 years into their AD and had advanced dementia. When further compared to 77 AD controls, matched for age of onset and duration, the seizure patients did not differ on medical illnesses, amount of medications, and degree of focal neuropathology. We conclude that a few unprovoked generalized seizures frequently occur late in the course of AD, and that AD patients with a younger age of dementia onset are particularly susceptible to seizures.

Phenotype of chromosome 14-linked familial Alzheimer's disease in a large kindred

We report the clinical and neuropathological features of chromosome 14-linked familial Alzheimer's disease (14qFAD) in affected members of the L family. Some clinical information on all 16 known affected individuals and detailed neuropathological findings in 6 family members were available for review. Common features of the phenotype of 14qFAD in the L family included onset of dementia before the age of 50, early progressive aphasia, early-appearing myoclonus and generalized seizures, paratonia, cortical atrophy, numerous and extensive senile plaques and neurofibrillary tangles, and prominent amyloid angiopathy. Descriptions of phenotypic features were available for six additional recently defined 14q-linked FAD kindreds: the findings in four of them (FAD4, FAD2, A, B) indicated a relatively consistently shared 14qFAD phenotype, conforming closely with the specific clinical and neuropathological characteristics noted in the L family. Comparisons also suggested several ostensible phenotypic variants in 14qFAD: (1) In two 14q-linked kindreds (SNW/FAD3, FAD1), affected individuals in some instances were noted to survive to age 70 or beyond and the mean age at onset (> 49 years) in these two kindreds was somewhat higher than in their five 14qFAD counterparts (< 48 years in each); (2) in the SNW/FAD3 kindred, seizures and myoclonus were absent in all 10 subjects examined; and (3) cerebellar amyloid plaques were variably present within and among several 14qFAD kindreds. Comparisons with phenotypic features recently detailed in three kindreds (TOR3, F19, ROM) with codon 717 amyloid precursor protein gene mutations (i.e., APP717 FAD) suggested several distinctions: Prominent progressive aphasia, myoclonus, seizures, and paratonia were all apparently less prevalent in APP717 FAD, with language function predominantly spared over the initial disease course. The extent of homogeneity and heterogeneity in the clinical and neuropathological phenotype of 14q-linked FAD and its possible meaningful distinctions from the phenotypes of APP717 FAD await further determination.

Quantitative EEG correlates of cognitive deterioration in the elderly

We report on the quantitative analysis of the EEG (QEEG), using the Neurometric method, in large samples of normal elderly; normal subjectively impaired elderly; patients with mild cognitive impairment; patients presenting with a continuum of primary cognitive deterioration from mild to moderately severe as measured by the Global Deterioration Scale (GDS), compatible with dementia of the Alzheimer's type (DAT). Neurometric QEEG measures were found to be a sensitive index of degree of cognitive impairment, especially reflected in increased absolute and relative power in the theta band, with delta increasing in later stages of deterioration. While these abnormalities were widespread, neither localized or lateralized, MANOVA's for GDS and relative power in theta reached highest significance in a bilateral temporo-parietal arc. A possible relationship between hippocampal dysfunction, cognitive deterioration, and theta abnormalities is discussed in relation to these findings. The results suggest that Neurometric QEEG features are sensitive to the earliest presence of subjective cognitive dysfunction and might be useful in the initial evaluation of patients with suspected dementia, as well as in estimating the degree of cognitive deterioration in DAT patients.

Alzheimer's disease: the problem of incorrect clinical diagnosis

We reviewed the medical records of eight patients clinically diagnosed with Alzheimer's disease who were found on autopsy to have neuropathologic findings inconsistent with Alzheimer's disease. The clinical criteria for the diagnosis of probable Alzheimer's disease from the National Institute of Neurological and Communicative Disorders and Stroke/Alzheimer's Disease and Related Disorders Association (NINCDS/ADRDA) were retrospectively applied to these patients. The patients presented with clinical features atypical for Alzheimer's disease early in the course of the disease, including focal neurologic findings, gait abnormalities, motor speech abnormalities, and extrapyramidal features. Attention to these clinical red flags may decrease the likelihood of misdiagnosis of Alzheimer's disease in a patient with a non-Alzheimer's disease cause of dementia.

Amine accumulation: a possible precursor of Lewy body formation in Parkinson's disease

It is now well recognized that the hypothalamus is an important site of neuropathology in Parkinson's disease (PD). Lewy bodies, a marker of nerve cell degeneration and a pathological hallmark of PD, have been observed frequently in the hypothalamus of PD patients by Lewy (1923) and other investigators and confirmed by more recent systematic studies by Langston & Forno (1978). Both Lewy and Langston & Forno found a predilection of Lewy body formation in specific hypothalamic nuclei with the tuberomammillary, lateral, and posterior areas containing by far the highest average counts per nucleus. Selective vulnerability of the tuberomammillary, lateral, and posterior hypothalamic cell groups to degeneration has been observed also in aging, postencephalitic Parkinsonism, Alzheimer's disease, and schizophrenia. The susceptibility of these particular nuclei to degenerative changes including Lewy body formation is not presently understood nor are the mechanisms by which Lewy bodies are formed in PD and other CNS disorders. Accumulation of amines, a pathological process which follows degeneration of catecholamine-containing neurons in experimental animals, also occurs most frequently in the lateral and posterior hypothalamic areas. In the present communication we propose that in PD, amine accumulation may be a precursor to Lewy body formation and that the susceptibility of certain hypothalamic areas to Lewy body formation may be related to their propensity to accumulate amines. Furthermore, the frequent co-existence of Lewy bodies and Alzheimer's neurofibrillary tangles in the lateral and posterior hypothalamic nuclei suggest that they may share a common pathogenetic etiology. If confirmed, this hypothesis may provide an experimental model by which the formation of Lewy bodies and neurofibrillary tangles may be investigated.

Cognitive profile of Alzheimer patients with extrapyramidal signs: a longitudinal study

The cognitive profile of Alzheimer patients without (ADE-, n = 17) and with (AD, E+, n = 15) extrapyramidal signs (rigidity or bradykinesia), at the time of diagnosis, was examined in a 3-year follow-up study and compared to cognitive performance of demented (PD D+, n = 18) and nondemented (PD D-, n = 17) patients with Parkinson's disease and normal elderly controls (n = 19). Although the AD E+ and AD E- groups did not differ significantly at the initial testing, the AD E+ patients showed greater deterioration on visual, praxic and expressive speech functions as well as in category memory. The cognitive profile of the AD E+ patients was similar to that of the PD D+ patients except that the AD E+ patients recognized more false positive targets on list-learning task. The AD E- patients had better preserved praxic functions and WAIS Performance IQ but they, like AD E+ patients, recognized more false positive targets on list-learning than the PD D+ patients did. The results suggest that AD patients with extrapyramidal signs, even if mild, at the time of diagnosis may have greater progression of cognitive impairment, especially on cortical functions, which may explain earlier need for institutional care observed in previous studies as compared to patients without these signs.

Quantitative analysis of the EEG during tonic REM sleep--methodology

Frequency and amplitude characteristics of the clinical (waking) electroencephalogram (EEG) can be diagnostically useful in neuronal degenerative disorders such as Alzheimer's or other cortical dementias. However, interpretation of the clinical EEG may be limited by many factors, including movement and muscle artifacts and uncontrolled variations along the alert/drowsy continuum. Moreover, the clinical EEG involves subjective judgement by experts whose opinions often differ. In an effort to address these problems, we have developed a computer-automated technology that examines the digitized, all-night sleep EEG for frequency and amplitude characteristics of potential diagnostic relevance to Alzheimer's dementia. Robust time series analysis techniques and a modified power spectral analysis (Z-spectra) are used to suppress artifactual information and to automatically select samples of tonic REM sleep EEG. The spectra (amplitude vs. frequency relationship) of this specific EEG state is then assessed for diagnostically relevant information.

Extrapyramidal signs in Alzheimer's disease: A 3-year follow-up study

Occurrence of extrapyramidal signs was investigated in a follow-up study of 32 patients with probable Alzheimer's disease (AD). Bradykinesia and rigidity were observed in 39% and 11% of the neuroleptic-free patients at entry and in 72% and 61% at year 3, respectively. Tremor was not a predominant feature nor did its occurrence increase over time. Use of neuroleptics contributed to extrapyramidal signs; 75-100% of the neuroleptic-treated patients showed bradykinesia, rigidity or orofacial dyskinesia. The homovanillic acid (HVA) concentrations of the cerebrospinal fluid at entry were comparable to those of age-matched controls. Nor did HVA levels correlate with rigidity or bradykinesia in these early AD cases. Presence of bradykinesia or rigidity at the initial evaluation predicted more severe dementia and a poor prognosis over the period of 3 years, although interaction of initial clinical severity of dementia was significant. Of 15 patients with these signs 3 (20%) died and 8 (53%) needed institutional care, while of 17 patients without these signs only 1 (6%) died and 2 (12%) were institutionalized by year 3 (p less than 0.01).

Increased insulin levels after OGTT load in peripheral blood and cerebrospinal fluid of patients with dementia of Alzheimer type

An investigation was carried out to determine whether a disturbance of glycometabolism is associated with dementia of Alzheimer type (AD). The first part of the study was carried out on 108 AD patients and 57 normal controls (NCs). Neither the plasma level of insulin nor that of glucose differed significantly between the two groups before the oral glucose tolerance test (OGTT), whereas there was a significantly greater increase of the plasma insulin in the AD group than in the NC group after the OGTT. The second part of the study was carried out on 54 AD patients, 44 patients with vascular dementia (VD), and 26 NCs. Early in the morning after overnight fasting, there was no significant difference in the fasting plasma level of either glucose or insulin, or the cerebrospinal fluid (CSF) level of glucose, among the three groups, However, the CSF level of insulin was significantly higher in the AD group than in the other two groups. These results suggest that an abnormally high level of insulin, not only in the peripheral blood after OGTT load but also in the CSF after fasting, may be associated with the pathology of AD.

Risk factors for neuroleptic-induced movement disorders

Chronic neuroleptic therapy may be associated with the development of diverse movement disorders including Tardive dyskinesia (TD), Parkinsonism, dystonia, and akathisia in a subset of schizophrenic patients. It is presently unknown why only a proportion of neuroleptic-treated patients develop these movement disorders. In the following communication, we present a series of studies which demonstrate that the development of these movement disorders may be facilitated by certain risk factors including disturbances in pineal melatonin functions, diabetes mellitus, cognitive deficits, suicidal behavior, and disturbances in the functions of the choroid plexus. Recognition of these biological factors may prove useful in: (a) further understanding of the pathophysiology of these disorders, and (b) identifying patients at risk for these movement disorders.

Care of demented patients with severe communication problems

Two time-studies and an interview study were carried out at a geriatric clinic. The aim was to elucidate how much time caregivers use for direct patient care in their contact with severely demented patients compared with non-demented patients as well as how they experience the care of demented patients in a task assignment care system. The analysis showed that more time was used to help non-demented patients than demented patients with the same ADL-performance. Five types of patient reactions to communicative attempts made by the caregivers were described: the patient seems to enjoy contact, he avoids contact, contact leads to aggression, he reacts only sporadically to contact and he does not show any reactions to it. The caregivers described negative reactions to demented patients with communication problems. Communication problems seem to be a threat to caregivers' commitment.

Extrapyramidal features in advanced Down's syndrome: clinical evaluation and family history

Extrapyramidal, frontal release, and other neurological signs were studied in 54 demented and non-demented patients with Down's syndrome (DS). Fourteen patients were demented and five showed extrapyramidal signs, mainly of the rigid-hypokinetic spectrum and similar to Parkinsonian features in advanced Alzheimer's disease (AD). None of the non-demented patients had Parkinsonian signs. The mean age of the demented DS patients with extrapyramidal signs was significantly higher than that of the patients without. Frontal release signs were present in demented and non-demented patients. A questionnaire showed no increase in either the proportion of early- or senile-onset dementia or Parkinsonism among first- and second-degree relatives of DS patients. Parkinsonian signs appear to be present at a lower frequency in DS than in advanced AD. A speculative hypothesis about a gene dosage effect of Cu/Zn-superoxide dismutase in preventing toxic radical formation in the substantia nigra of DS patients is presented.

Parkinsonian features in advanced Down's syndrome

The results of a clinical study on extrapyramidal, frontal release, and other neurological signs in 54 demented and non-demented patients with Down's syndrome (DS) are presented. Fourteen patients were demented, five of them showed extrapyramidal signs, mainly of the rigid-hypokinetic spectrum and rather similar to Parkinsonian features in advanced Alzheimer's disease (AD). None of the non-demented patients had Parkinsonian signs. The mean ages of the demented DS patients with extrapyramidal signs was significantly higher than that of the patients without the respective signs. Frontal release signs were present in demented and nondemented patients. From a questionnaire neither a raised proportion of early- or senile-onset dementia nor of Parkinsonism among first- and second-degree relatives of DS patients could be traced. Parkinsonian signs seem to be present at a lower frequency in DS than in advanced AD. A speculative hypothesis about a gene dosage effect of Cu/Zn-superoxide dismutase in preventing toxic radical formation in the substantia nigra of DS patients is presented.

Diffuse Lewy body disease: correlative neuropathology using anti-ubiquitin immunocytochemistry

Diffuse Lewy body disease is an important pathological substrate of the common syndrome of parkinsonian dementia. The new technique of anti-ubiquitin immunocytochemistry has been used in a correlative quantitative neuropathological study of fifteen cases of diffuse Lewy body disease, showing that the severity of dementia is related to cortical Lewy body density, whilst subcortical abnormalities make a much less significant contribution. Cortical senile plaques also appear to be part of the pathology of diffuse Lewy body disease and should not therefore be used as an isolated diagnostic criterion for Alzheimer's disease. Diagnostic criteria for diffuse Lewy body disease are discussed.

Neuropathological distinction between Parkinson's dementia and Parkinson's plus Alzheimer's disease

The distinctive clinical features of dementia in Parkinson's disease (PDD) and Parkinson's plus Alzheimer's disease (PD + AD) suggest different patterns of cerebral atrophy in these conditions. To determine the pathoanatomical substrates of dementia in PDD and PD + AD, morphometric analysis of 5 standardized coronal slices was used to identify volumetric changes in cerebral tissue. In PDD (n = 4) there were 9 to 23% reductions in cross-sectional area of cerebral cortex, a 38% loss of tissue in the globus pallidus + putamen, and an 18% reduction in area of the amygdala, whereas in PD + AD (n = 6) there was severe global atrophy of the cerebral cortex (27-29% reductions), moderate atrophy of white matter (10-19% reductions), and 40% reductions in areas of globus pallidus + putamen and the amygdala relative to neuropathologically intact controls (n = 14). Immunostaining with anti-glial fibrillary acidic protein disclosed significant gliosis of all four major subdivisions of neocortex in PD + AD and gray matter of the caudate, putamen, globus pallidus, and thalamus in both PDD and PD + AD relative to controls. The findings suggest that dementia in PDD is mainly subcortical in origin and due to neuronal degeneration in basal ganglia, the amygdala, and thalamus. In PD + AD the same pattern and degree of subcortical degeneration is evident, but there are clearly superimposed lesions involving cortical neurons and long projection fibers coursing through cerebral white matter that most likely account for the distinctive manifestations of dementia in this condition compared with PDD.

Feeding problems in severely demented patients seen from task and relationship aspects

This study aimed at increasing the understanding of feeding problems in severely demented patients cared for in a task assignment system. Twenty-three video-recordings made during the feeding of 15 severely demented patients and 55 focused interviews with 45 caregivers, who fed the 15 patients during that period were analysed regarding the feeding problems seen from a task aspect and from a relationship aspect. The result indicated that the problems were partly of a more constant nature and partly fluctuated from meal to meal. Feeding problems regarding the task aspect were mentioned first by the caregivers in the interviews in spite of the fact that the patients had severe communication problems which could be expected to cause great problems in the relationship between the patient and his caregiver. Reasons for these findings are suggested.

Parkinsonism and neurofibrillary tangle pathology in pigmented nuclei

Four parkinsonian patients had neurofibrillary tangles, neuronal loss, and gliosis restricted to the substantia nigra and locus ceruleus. No Lewy body inclusions or other neuropathological changes accounting for parkinsonism were found in any of these patients. Their clinical features were characterized by an early age of onset, absence of dementia, absence of other neurological abnormalities, good response to drug therapy, and a long, slowly progressive course of illness. None of the patients had any history of encephalitis. These patients either represent a forme fruste of postencephalitic parkinsonism or a new entity thus far not described.

Dementia and Parkinson's disease

Recent research into the dementia of Parkinson's disease has exposed a complex area in which it has not always been possible to match clinical and pathological observations. Certain neuropsychological deficits result from a disruption of basal ganglia and frontal lobe interactions. These are unrelated to a global dementia, the prevalence of which exceeds twice that in the normal population. The associated pathological lesions comprise cortical pathology, either Alzheimer's disease or Lewy bodies, in combination with moderate degeneration of the subcortical, cholinergic, basal nucleus of Meynert.

The neurobiology of Alzheimer's disease

The defining histological characteristics of Alzheimer's disease (AD) are neurofibrillary tangles and neuritic plaques, although neither is pathognomonic for this disorder. The distribution of AD histopathology suggests selective neuronal vulnerability, with specific cell populations affected within discrete regions of the cerebral hemispheres and within certain subcortical and brain-stem nuclear areas. At the ultrastructural level, tangles and plaque neurites contain paired helical filaments whose composition is unknown but may include altered cytoskeletal elements. Amyloid, deposited in plaque cores and often focally present within the cerebral vasculature, contains a polypeptide ("beta-protein," or "beta-amyloid") encoded by a chromosome 21 gene. At least in occasional families, AD has been linked to a separate chromosome 21 locus, but different underlying genetic factors may operate in other cases. Inorganic substances, including aluminum and silicon, are reported to co-localize within tangle-bearing neurons and plaque cores. Specific environmental agents have not been confirmed to be pathogenetically important, however, but may eventually prove to exert a permissive, facilitatory, or even causative role in many AD patients.

Cortical Lewy body dementia: clinical features and classification

Seven patients, aged 65-72 years, are described with dementia and cortical Lewy bodies. In one patient a Parkinsonian syndrome was followed by dementia and motor neuron disease. In the remaining six patients dementia was accompanied by dysphasia, dyspraxia and agnosia. One developed a Parkinsonian syndrome before the dementia, in three cases a Parkinsonian syndrome occurred later, and in two cases not at all. All patients showed Lewy bodies and cell loss in the substantia nigra, locus coeruleus and dorsal vagal nucleus, as in Parkinson's disease. The severity of cell loss in the nucleus basalis varied from mild to severe. Lewy bodies were also present in the parahippocampus and cerebral cortex, but Alzheimer-type pathology was mild or absent, and insufficient for a diagnosis of Alzheimer's disease. Patients with moderate or severe dementia, some with temporal or parietal features, may have cortical Lewy body disease, Alzheimer's disease, or a combination of the two. Cortical Lewy body disease may be associated with dementia in Parkinson's disease more often than realised, but is not necessarily associated with extensive Alzheimer pathology.

The substantia nigra and ventral tegmental area in Alzheimer's disease and Down's syndrome

Degenerative changes in the substantia nigra and ventral tegmental area were investigated in 104 cases of Alzheimer's disease and 13 cases of Down's syndrome. Frequencies of tangles in three groups of patients with Alzheimer's disease were 86%, 44% and 46% (54% overall) respectively. About half of those with tangles, but no Lewy bodies, had excess nigral cell loss, and 16% had moderate or severe neuronal fallout, but none had a Parkinsonian syndrome. Cases with nigral tangles were younger, tended to have more hippocampal and cortical tangles and plaques, and lower activities of cortical choline acetyltransferase. In most cases of Alzheimer's disease degeneration in nigral and tegmental areas was greater than controls, and tangles were evenly distributed. All the cases of Down's syndrome had tangles in the nigra and eight showed mild cell loss. Mild degenerative changes accompanied by tangles in the substantia nigra and ventral tegmental area are common in Alzheimer's disease, but severe cell loss is rare. When a Parkinsonian syndrome occurs in Alzheimer's disease it is likely to be due to Lewy body pathology.

Psychiatrists and Alzheimer's disease

Psychiatric symptoms in Alzheimer's disease are not specific: anxiety, agitation, depression, memory disorders, mental confusion. Of these disorders, depression is the most accessible of these to pharmacological treatment; agitation, however, raises the institutional problem. Throughout the inexorable evolution of the disease, the psychiatrist has to pay attention to the global situation: medical, social and legal.

Psychotic symptoms and the longitudinal course of senile dementia of the Alzheimer type

Delusions, misidentifications and hallucinations occur frequently throughout the course of senile dementia of the Alzheimer type (SDAT). Rates of psychosis among subjects with moderate to severe SDAT range from 42% to 84% in our study group; at least half of persons with SDAT with no prior psychiatric history will display psychosis at some point during the course of dementia. Furthermore, psychotic symptoms are associated with accelerated cognitive deterioration, but not with increased mortality.