Presenile dementia: the difficulties of early diagnosis

Functional cognitive disorders: a systematic review

Cognitive symptoms are common, and yet many who seek help for cognitive symptoms neither have, nor go on to develop, dementia. A proportion of these people are likely to have functional cognitive disorders, a subtype of functional neurological disorders, in which cognitive symptoms are present, associated with distress or disability, but caused by functional alterations rather than degenerative brain disease or another structural lesion. In this Review, we have systematically examined the prevalence and clinical associations of functional cognitive disorders, and related phenotypes, within the wider cognitive disorder literature. Around a quarter of patients presenting to memory clinics received diagnoses that might indicate the presence of functional cognitive disorders, which were associated with affective symptoms, negative self-evaluation, negative illness perceptions, non-progressive symptom trajectories, and linguistic and behavioural differences during clinical interactions. Those with functional cognitive disorder phenotypes are at risk of iatrogenic harm because of misdiagnosis or inaccurate prediction of future decline. Further research is imperative to improve diagnosis and identify effective treatments for functional cognitive disorders, and better understanding these phenotypes will also improve the specificity of diagnoses of prodromal degenerative brain disease.

A longitudinal study of physical function in patients with early-onset dementia

Background

The aim of this study was to explore changes in mobility in terms of ambulation and transfer over 1 year in patients with early-onset Alzheimer's disease (EOAD), and to compare mobility in EOAD with patients with other types of early-onset dementia (EOOD).

Method

Forty-two patients with EOAD and 30 patients with EOOD were included. All patients were home-dwelling and had mild or moderate degree of dementia. Mobility was assessed using the Timed Up and Go Test (TUG), a modified version of the Clinical Outcome Variables Scale, timed stair walking, and timed rise from the floor.

Results

The EOAD group performed significantly better than the EOOD group on all mobility tests. After 1 year, 25 persons with EOAD were tested again. The performance on TUG (p = 0.028) and stair walking (p = 0.02) had deteriorated at the 1-year follow-up in the EOAD group.

Conclusion

Patients with EOAD performed better on mobility tasks than patients with EOOD, but their performance deteriorated at 1-year follow-up.

Pseudodementia, a term for its time: the impact of Leslie Kiloh's 1961 paper

OBJECTIVE

It is 50 years since Leslie Kiloh's paper titled "Pseudo-dementia" was published. The present article aims not only to honour the work and achievements of Professor Kiloh, but also to consider the impact and importance of that 1961 paper.

CONCLUSIONS

Kiloh presented vignettes concerning 10 patients, most of whom presented with depressive features. The term "pseudodementia" had been used previously. However, Kiloh's paper gave impetus to psychiatrists to focus on the potential reversibility of cognitive impairments that might be attributable to psychiatric disorders (depression, schizophrenia and conversion disorder among them). The historical context of the paper needs to be highlighted; it was written at a time when dementia was defined as being irreversible. Outcome studies and ongoing research have shown that cognitive deficits in cases of depression commonly cannot be fully reversed, and commonly herald emergence of an underlying progressive dementing disorder. Nevertheless, it is argued that the term has remained useful in fostering discussion of potentially treatable psychiatric symptoms, even in cases of progressive dementia.

Younger people with dementia: diagnostic issues, effects on carers and use of services

OBJECTIVE

To determine difficulties experienced by carers of younger people with dementia.

DESIGN

Cross-sectional questionnaire survey.

PARTICIPANTS

102 eligible carers of persons less than 65 years of age with dementia, recruited through support groups and clinicians' referrals.

MAIN OUTCOME MEASURES

Problems with diagnostic process; professionals/services consulted; psychological, physical, occupational and financial impact of illness on carers and children; use of and satisfaction with services.

MAIN RESULTS

Diagnostic problems were reported by 71% of carers. Mean time until diagnosis was 3.4 years (SD 2.8) after consulting 2.8 (1.4) professionals. Carers reported frustration (81%) and grief (73%). Adverse psychological effects were common, more so in female than male carers (p < 0.01). The younger the carer, the more psychological and physical effects were experienced (p < 0.01). Only 8% of carers considered that their children had encountered no problems because of the dementia. Of 61 working carers, 59% reduced their hours or stopped working after diagnosis, and 89% of all carers had experienced financial problems subsequent to diagnosis. Most carers (89%) had used a support service, but 25% had never used community support, 32% had never used respite. Proportions of carers rating services as good ranged between 43 and 100%.

CONCLUSIONS

Younger people with dementia, and their carers, face difficulties in obtaining a diagnosis. Carers also experience psychological problems, financial worries, loss of employment and family conflict, and their children are affected. Most carers had used services, but some dissatisfaction existed.

The spectrum of depressive pseudo-dementia

Depressive disorder causes cognitive symptoms. In the case of severe cognitive symptoms or when psychometric procedures measure cognitive decline in the range of dementia, depressed patients may be diagnosed as Depressive Pseudo-Dementia (DPD). There is no data that depressive disorder can cause dementia without coexisting depressive symptoms. The latter symptoms are frequently overseen because cognitive symptoms are equated with organic brain disease. There are typical neuropsychological features of cognitive decline in depressive disorders, like psychomotor retardation and the slow-start phenomenon. Most patients referred to as DPD, suffer from depression-induced cognitive symptoms outside the range of dementia, but complain of memory disturbance and inability to think or concentrate. The diagnosis of DPD draws attention to a problem in the diagnosis of psychiatric disorders in the elderly: Old people suffering from depression are at particular risk of being labelled as demented. The most important step to diagnose depression causing dementia is the search for signs and symptoms of affective disorder even after having found cognitive symptoms.

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.

"Hysteria" in clinical neurology

Hysteria is an ancient word for a common clinical condition. Although it no longer appears in official diagnostic classifications, "hysteria" is used here as a generic term to cover both "somatoform" and "dissociative" disorders as these are related psychopathological states. This paper reviews the clinical features of four hysterical syndromes known to occur in a neurologist's practice, viz conversion, somatization and pain disorders, and psychogenic amnesia. The presence in the clinical history of a multiplicity of symptoms, prodromal stress, a "model" for the symptom(s), and secondary reinforcement all suggest the diagnosis, and minimise the need for extensive investigations to rule out organic disease. Psychodynamic, behavioral, psychophysiologic and genetic factors have been proffered to explain etiology. Appropriate treatment involves psychotherapeutic, behavioral and pharmacological techniques. A basic requirement is to avoid errors of commission such as multiple specialist referrals and invasive diagnostic and treatment procedures. Hysteria is a remediable condition if identified early and managed appropriately.

Effects of major depression on the cognitive function of younger and older subjects

The effects of age and depression on cognitive function were investigated in two groups of in-patient major depressives aged under and over 60 years who were tested when depressed and after recovery. The majority of the tests showed impaired performance during depression with improvement after recovery, and also differences between the two age-groups in both the depressed and recovered phases. However, the older subjects were not more severely affected by depression than the younger subjects. The pattern of impairment associated with depression was different to that associated with older age: depression affected performance on more 'complex tasks', whereas age was associated particularly with slowing on timed tests. This study did not suggest that the impairment from baseline due to the depression is greater in the elderly than in younger subjects.

[Depressive pseudodementia. Diagnostic importance of quantified EEG]

The accuracy of computerized EEG to discriminate depressive pseudodementia from dementia was evaluated in 12 inpatients with recent cognitive impairments (all with DSM III R diagnosis of dementia). EEG were performed during wash-out period, then all subjects underwent an ECT and/or antidepressant trial. After this trial, clinical improvement was significant for six patients, while the six others remained unimproved. According to these two groups, electrophysiological data were retrospectively compared. Discriminant stepwise analysis exhibited that the combination of two parameters: symmetry of occipital alpha power and frontal alpha/theta ratio, was able to discriminate future responders from non responders patients with a greater accuracy than clinical and classical EEG parameters.

Pseudodementia: a slow death

The clinical term "pseudodementia" has remained a permanent nosological entity in the literature for over 100 years. Indeed, recognition of the fact that clinical symptoms associated with reversible neuropsychiatric conditions can mimic irreversible disorders was known as early as the middle of the 19th century. The importance of the term lies in the inherent assumption that the presenting dementia is not real, or is at least reversible, and therefore treatable. Nonetheless, there continues to be controversy regarding the validity and appropriate clinical use of the term. This article reviews the evolution and clinical utility of the term pseudodementia and attempts to redirect investigative efforts toward an understanding of the neuroanatomical substrates that underlie depression and cognitive impairment in the elderly. Based on a critical analysis of the relevant literatures, a subcortical-frontal neuroanatomical substrate of late-life depression is supported. Further, the presence of leukoaraiosis, as measured by magnetic resonance imaging, is proposed as a potential neurobiological marker that contributes to the depressed mood, cognitive impairment, and later cognitive deterioration of some elderly depressed.

Some aspects of memory disorders clearly distinguish dementia of the Alzheimer's type from depressive pseudo-dementia

Two groups of patients affected by mild dementia of the Alzheimer's type (n = 42) or by depressive pseudo-dementia (n = 26) were given a modified version of the Rey's Auditory Verbal Learning Test. The two groups were roughly matched for overall level of cognitive impairment. The main purpose of the research was to determine if some aspects of their memory disorders distinguished the two diagnostic groups. Comparison between results obtained on recall and on recognition measures was of little diagnostic usefulness in distinguishing dementia of the Alzheimer's type (DAT) from depressive pseudo-dementia (DPD). A marked prevalence of the recency over the primary effect in immediate recall, a high rate of forgetting, and the presence of many intrusion errors on delayed recall were observed more frequently in DAT than in DPD patients. None of these indices, however, was sensitive and specific enough to allow a confident diagnostic discrimination at the individual case level. The memory measure which best distinguished DAT from DPD patients was the presence of several false positive errors on delayed recognition because DAT patients adopted a very liberal response bias, endorsing many false recognition errors, whereas DPD patients adopted a conservative criterion and tended to miss real stimuli, rather than making false recognition errors.

Brief neuropsychologic differentiation of demented versus depressed elderly inpatients

Recent investigations have suggested the utility of brief, psychometric screening batteries in the early detection of abnormal mental decline. This study extended the investigation of one of these batteries, comprised of three tests (Controlled Oral Word Association, Visual Retention, Temporal Orientation), to the difficult issue of differentiating dementia from depression in a hospitalized sample composed of a group of depressed only patients (N = 50) vs an age-matched demented group (N = 50), some of whom presented mixed dementia/depression syndromes. Demented patients consistently performed more poorly as a group than depressed patients on each of the three measures. This was the case even when three-group (demented only, mixed demented/depressed, depressed only) comparisons were conducted. Impairment was more common on one or more tests with demented vs depressed patients. However, limitations for screening purposes and for the definitive detection of dementia were noted in view of only moderate predictive power of the tests with discriminant function analysis. Nevertheless, the potential clinical utility of the three tests in the general hospital and other primary care settings was apparent.

Clinically diagnosed presenile dementia of the Alzheimer type in the Northern Health Region: ascertainment, prevalence, incidence and survival

Potential cases of presenile dementia of the Alzheimer type (PDAT) in the Northern Health Region (estimated population aged 45-64, 655,800) were ascertained for the years 1979-86 from in-patient ICD-9 codes and other sources. An algorithm was applied to the casenote information to distinguish between Alzheimer-type and other forms of dementia. A search of the NHS central register was made to establish date and place of death. Estimates were made for patients with missing case records. The point prevalence rate for PDAT was estimated as 34.6 per 100,000 with an annual incidence of 7.2 per 100,000 in the 45-64 age range. These rates are compared with those reported in other studies. Five-year survival following diagnosis for incident cases of PDAT was 64% with a longevity quotient (LQ), the percentage of expected time actually survived, of 69%. There was no evidence of a more malignant course in PDAT when compared with survival in older patients with dementia of the Alzheimer type (DAT) in other studies. Sixty-six per cent of deaths occurred in hospital, 19% at home and 15% in residential homes.

Regional cerebral blood flow abnormalities in depressed patients with cognitive impairment

Depression with cognitive impairment, so called depressive pseudodementia, is commonly mistaken for a neurodegenerative dementia. Using positron emission tomography (PET) derived measures of regional cerebral blood flow (rCBF) a cohort of 33 patients with major depression was studied. Ten patients displayed significant and reversible cognitive impairment. The patterns of rCBF of these patients were compared with a cohort of equally depressed non-cognitively impaired depressed patients. In the depressed cognitively impaired patients a profile of rCBF abnormalities was identified consisting of decreases in the left anterior medial prefrontal cortex and increases in the cerebellar vermis. These changes were additional to those seen in depression alone and are distinct from those described in neurodegenerative dementia. The cognitive impairment seen in a proportion of depressed patients would seem to be associated with dysfunction of neural systems distinct from those implicated in depression alone or the neurodegenerative dementias.

Akinesia: a syndrome common to parkinsonism, retarded depression, and negative symptoms of schizophrenia

A distinct hypokinetic syndrome appears to exist across several different neuropsychiatric diagnoses, involving (1) slowed motor activity with difficulty initiating and sustaining behaviors, (2) anhedonia with depressed mood and reduced affective range, and (3) cognitive impairment. Specifically, three well-recognized states--parkinsonism, retarded depression, and the negative symptoms of schizophrenia--prominently feature the components of this syndrome, and reduced dopamine turnover in the brain has been hypothesized to play a part in the pathophysiology of each. While aspects of this conceptualization remain controversial, it generates testable hypotheses that could have implications for the understanding and treatment of these states.

Depressed mood and its relationship to neuropsychological test performance in HIV-1 seropositive individuals

The relationship between depression and neuropsychological test performance in HIV-1 seropositive individuals is unclear. The present study was conducted to determine whether different patterns of neuropsychological test performance would be present in depressed vs. nondepressed individuals infected by the Human Immunodeficiency Virus (HIV-1). It was hypothesized that subjects evidencing depressed mood would demonstrate greater difficulty on measures of neuropsychological function. The subjects were 54 mostly symptomatic HIV-1 seropositive homosexual/bisexual males aged 20 to 60. A neuropsychological test battery together with the Beck Depression Inventory (BDI) was administered to all subjects. Stepwise multiple regression analysis revealed a significant relationship only between scores on the BDI and the Grooved Pegboard test and Trial 6 of the RAVLT. Subjects were then dichotomized using the BDI into high-BDI (M = 28.9) and low-BDI (M = 6.3) groups. Analysis of variance failed to reveal significant group differences between the depressed vs. the non-depressed groups on the neuropsychological measures despite their marked separation on the BDI. Similarly, examination of individual neuropsychological outliers again failed to demonstrate an increased number of outliers in the high- and low-BDI groups. These results suggest that the presence of clinically significant levels of depression in a non-elderly HIV-1 seropositive sample does not necessarily lead to significant neuropsychological dysfunction.

Tailoring adult psychiatric practices to the field of geriatrics

The United States' population is aging. Epidemiological surveys suggest significant rates of mental illness amongst the rapidly growing over-65 cohort. A burgeoning experience and data base related to the developing sub-discipline of geriatric psychiatry is now available. This article synthesizes key issues and concepts as an introduction to geropsychiatric practice-in particular, a) the interface between medical illness and psychiatric expression in the elderly, b) delirium, c) dementia, and d) depression-and considers their interactions. Finally, there is a brief overview of geriatric psychopharmacology, followed by clinically-oriented discussions of each of the major classes of psychotropics as applied to a geriatric population.

Potentially reversible dementia: a review

Potentially reversible dementia is reviewed with reference to diagnosis, causes and outcome. Many disorders which cause cognitive impairment, such as drug toxicity and depression, fail to meet diagnostic criteria for dementia. These tend to have the best prognosis. Studies of the neuropsychiatric syndromes associated with disorders causing potentially reversible dementias suggest that dementia is an infrequent outcome and when it does occur, few cases recover. Factors predictive of improvement are short duration of symptoms and mild degree of cognitive impairment, usually subcortical in type. It is suggested that potentially reversible cognitive impairment would be a more accurate term as many cases are due to delirium and depression. While cases of well established dementia do not require extensive investigation, all cases should have a thorough clinical assessment as in many instances dual pathology exists and all require psychosocial management.

Depressive disorders and dementia: the clinical view

The relationship between depression and dementia is complex. Transient emotional disturbances and long-lasting depressive disorders may occur as psychological reactions to the loss of mental abilities or as behavioural manifestations of brain injury. On the other hand, major depressive disorder of late onset or of a recurrent type may be superimposed on dementing illness. Depression, particularly in elderly individuals, can manifest itself as a reversible syndrome of dementia that responds favourably to antidepressant treatment. It is not known whether the dementia syndrome of depression represents a quantitative intensification of minor cognitive impairments that can be observed in a large proportion of depressed patients. It also remains doubtful whether dementia in depressed patients has to be considered as an epiphenomenon of pervasive melancholic illness. An alternative explanation would look at such conditions as manifestations of a specific brain dysfunction. Major depression associated with cognitive impairment in stroke patients might be regarded as an example of a reversible dementia dysfunction.

Cognitive event-related potentials and reaction time in presenile subjects with initial mild cognitive decline or probable Alzheimer-type dementia

The so-called contingent negative variation (CNV) is a slow brain potential representing a complex of variously overlapped "endogenous" components of behavior related to different reasonably well-known neurocognitive processes. CNV complex evoked with a standard paradigm (S1-2 sec-S2-motor response) and reaction time (RT) to imperative signal (S2) were recorded and measured in 11 patients with initial presenile idiopathic cognitive decline (PICD), 8 with presenile Alzheimer-type dementia (PAD) and 10 healthy age-matched controls. Significant group differences were obtained for measures of some CNV components, particularly of the late pre-S2 CNV. No significant CNV activity, very prolonged RTs and sometimes characteristic post-imperative negative variation (PINV) were observed in the majority of patients with PAD. These results suggest that CNV complex and RT changes similar to those observed in our patients may constitute a valuable clue for the study of pathophysiological brain functioning in the early stages of presenile idiopathic mental deterioration.

Pseudodementia twelve years on

This paper reports a longitudinal study of 19 patients diagnosed as having pseudodementia more than a decade earlier. In only one patient was the earlier diagnosis changed to definite dementia and, in this patient, there were strong indicators that such a diagnosis should have been made initially. In a second patient, dementia could not be excluded. The remaining patients did not show evidence of a dementing illness and the courses of the illnesses resembled the primary psychiatric disorders responsible for the pseudodementia. The results validate the clinical utility of the term "pseudodementia".

[Current concept of pseudodementia]

The concept of pseudodementia was coined in the late XIXth century to refer to a syndrome mimicking dementia, but without underlying neurological lesions. Depressive disorders represent the main etiological factor and may present under two different forms, either "depressive cognitive disorders", or the more severe feature of "Wernicke's pseudodementia". The main issue remains diagnosing pseudodementia form organic dementia, especially from cortical degenerations of the Alzheimer type. Thus, the recognition of this clinical syndrome represents an alternative to the diagnosis of dementia which may lead to earlier and more effective psychiatric treatment. Recently, diagnostic criteria have been proposed to facilitate this distinction. Such criteria include clinical history, neuropsychological features, biological findings (dexamethasone suppression test and plasma MHPG) and electroencephalographic sleep studies. Finally, from a theoretical point of neurological conception of depression as well as for current hypotheses on the relationship of this last one with dementia.

Season of birth in Alzheimer's disease

Variation in quarter of birth was examined in patients with a clinical diagnosis of AD. There was a significant excess of first-quarter births among AD patients as compared with the expected birth rates derived from an age-matched census sample. This finding was due entirely to the significant excess of first-quarter births in AD patients without a family history of dementia. No seasonal variation was found in the birth dates of other clinical groups.

Structural brain CT changes and cognitive deficits in elderly depressives with and without reversible dementia ('pseudodementia')

Twenty-six elderly (greater than 60 yrs) patients with DSM-III major depression were compared to 13 patients with NINCDS/ADRDA probable Alzheimer's disease (AD), and to 31 screened normal controls. Subjects were matched on age and sex. Fifteen of the 26 depressed patients were cognitively impaired on the Mini-Mental State Examination (MMSE) upon admission, but after treatment returned to the normal range. These 15 patients were defined as having the dementia syndrome of depression (DOD). The remaining 11 depressed patients were termed depressed, cognitively normal (DCN). All subjects received standardized cranial CT scans for assessment of ventricular brain ratio (VBR) and CT attenuation numbers. Subjects also received neuropsychological evaluation. CT values for the 26 depressed patients lay between those of AD patients and normal controls. CT values for the DOD subgroup clustered near those of AD patients. Patterns of cognitive deficits and correlations of CT attenuation values with cognitive measures were also similar in AD and DOD. Most patients were reassessed at a mean of two years after initial testing; of the 11 of the 15 DOD re-examined, only one had undergone cognitive decline. By contrast, all AD patients retested had declined significantly. Episodes of DOD and DCN tended to 'breed true'. This study suggests that while patients with DOD may have underlying structural brain abnormalities, obvious short-term progression to AD does not commonly occur.

Patterns of performance on the Fuld Object Memory Evaluation in elderly inpatients with depression or dementia

The Fuld Object Memory Evaluation (Fuld, 1981) was administered to 80 elderly adults (aged 60 to 90 years) who were hospitalized for evaluation and treatment of primary degenerative dementia (PDD), other organic disorders (e.g., Parkinson's disease or multi-infarct dementia), or major depression. Although mean performance in each of the diagnostic groups was below normative levels reported by Fuld (1981), PDD patients performed significantly more poorly than those with depression or other organic disorders. Analysis of subscore patterns failed to support the hypothesis of a selective memory deficit in depression, and substantial overlap in scores was observed between the depressed group and patients with organic disorders other than PDD. Object Memory Evaluation performance was influenced by global mental status and secondary psychiatric diagnoses, but not by education, age, or physical health.

HLA antigens in depressed, demented, and nondemented elderly

To identify HLA antigen associations with geriatric depression, the authors typed 36 elderly patients with major depression and, for comparison, 36 patients with Alzheimer-type dementia and 29 nondemented elderly controls. The frequency for antigen Aw32 was significantly higher in the group of patients with major depression (14%) than in the demented (0%) and control (3%) groups. The frequencies for antigens Aw32 (22%) and Bw51 (22%) were significantly higher in the subgroup of 23 patients with endogenous depression than in the demented (Aw32 = 0%; Bw51 = 11%) and the control (Aw32 = 3%; Bw51 = 0%) groups. Although these results were derived from a relatively small sample (n = 101) and become nonsignificant when corrected for multiple comparisons, they suggest that HLA antigen associations may be present for only certain depressive subtypes in geriatric depression.

EEG findings in depressive pseudodementia and dementia with secondary depression

We report EEG findings in 33 elderly patients with mixed symptoms of depression and dementia, followed longitudinally to confirm diagnosis. Two groups of patients, dementia with depressive features (mixed-DEM, group I, n = 23) and patients with depressive pseudodementia (mixed-DEP, group II, n = 10), were defined. In addition, we also included, for comparison purposes, 35 patients with probable AD without depressive features (group III), 23 patients with major depression without cognitive impairment (group IV), and 61 healthy elderly controls (group V). We found significant group differences on waking EEGs between those mixed patients who did well after treatment for depression (depressive pseudodementia) compared to patients having dementia with secondary depression. The differences paralleled those between the 'pure' groups of demented and depressed patients. In patients with either depression or depressive pseudodementia, the EEG was usually normal or showed only mild abnormalities. In contrast, the majority of patients with either dementia or dementia with secondary depression had abnormal EEGs, with approximately one-third having moderate (or severe) abnormalities. Although the EEG was usually normal or only mildly abnormal in patients with pseudodementia or depression, these groups (II and IV) did show a significant slowing of the dominant posterior rhythm compared to controls. They also had a higher percentage of generalized abnormal EEGs than controls and this difference was significant between group IV (depression) and controls.

Dexamethasone suppression test in dementia and depression. Clinical and biological correlates

To determine the usefulness of the DST in differentiating depression from dementia, the test was administered to three diagnostic groups of psychogeriatric patients: depression; dementia; and dementia with depression. Clinical assessments were supplemented by ratings on the HRSD and SCAG, as well as by EEG and CT. All three groups showed a high incidence of abnormal DST results unrelated to presence or severity of affective symptoms, but showing a better association with SCAG and its 'organic' subsets. The mechanism(s) underlying these abnormal results may reflect organic brain disease. The usefulness of the DST in differentiating depression from dementia in the elderly was not confirmed.

Computerized electroencephalography in the evaluation of early dementia

In elderly patients presenting to an ambulatory practice with complaints of cognitive disturbance, early dementia must be differentiated from depression. The present paper describes the application of standard electroencephalography and evoked potential testing (EEG/EP) and computerized electroencephalography with evoked potential mapping (CEEG/EPM) in the analysis of 64 elderly patients complaining of cognitive disturbance. Although previous reports have claimed a sensitivity level of up to 80% for EEG in demented patients, it appears that a lower sensitivity (37% for EEG alone and 61% for EEG/EP) may be expected at the time of early presentation according to the present study. No EEG/EP abnormalities were detected in patients with depression. In demented patients, CEEG/EPM was abnormal in 85% (46 of 54) of cases compared to 10% (1 of 10) of cases with depression. Specific information was obtained from EEG/EP studies that helped differentiate the various causes of dementia in three cases. In CEEG/EPM studies, a pattern of relative suppression of alpha activity or suppressed auditory P300 amplitude in the posterior parietal regions was observed in 11 or 23 (48%) patients with Alzheimer's disease and 2 of 31 (6%) patients with other forms of dementia. None of the depressed patients demonstrated such changes. Based on the present study, it appears that computerized techniques may hold promise as an adjunct to standard EEG evaluation of patients with mild cognitive change in whom diagnosis of dementia or depression is in doubt. Although standard EEG rarely demonstrates characteristic changes that may help differentiate causes of dementia, CEEG/EPM appears to demonstrate, on occasion, abnormalities in the posterior temporal and parietal regions in patients with a diagnosis of probable Alzheimer's disease and rarely in other forms of dementia or depression.

Validation of clinical diagnostic criteria for Alzheimer's disease

Clinical investigations of Alzheimer's disease (AD) have been limited by diagnostic inaccuracy. We employed explicit clinical inclusion and exclusion criteria to identify subjects with senile dementia of the Alzheimer type (SDAT). In a consecutive series of 26 postmortem examinations from this sample, AD was histologically verified in all subjects and was the primary dementing illness. Seventeen of the 26 SDAT subjects had been diagnosed when only mildly demented. Two control subjects were examined neuropathologically; AD was absent in both. We conclude that research clinical diagnostic criteria for SDAT, even in its mild stage, are valid.

Dexamethasone suppression test and response to antidepressant therapy in psychogeriatric patients

Senile dementia patients show a high incidence of abnormal Dexamethasone Suppression Test (DST) which has been suggested to reflect the presence of atypical or subclinical depression; this study was designed to test this hypothesis. Thirty-six patients, diagnosed as suffering from dementia and/or depression on the DSM-III criteria, participated in the study. They were divided into three groups. dementia (12), depression (12) and dementia with depression (12). The results indicated that although patients with depression alone responded well to antidepressant therapy, no improvement occurred in patients with dementia. Demented patients who had clinical depression also showed a poor response. The response to treatment was unrelated to the DST status of the patients. It is concluded that abnormal DST in dementia patients is not indicative of a masked affective state, and antidepressants have no place in the management of dementia patients who have a positive DST but no overt affective symptoms.

The role of clinical neuropsychology in the neurological diagnosis of Alzheimer's disease

This survey on the early diagnosis of Alzheimer's disease (AD) reinstates the role of clinical neuropsychology in describing the cognitive status of AD and its evolution. The role of clinical neuropsychology is restricted to the clinical diagnosis of organic mental deterioration and its contribution to the diagnosis of AD is separate from that of neurology and neuroradiology. The frequency of a single neuropsychological disturbance in early AD patients is illustrated by our own observations.

Dementia during the seventeenth and eighteenth centuries: a conceptual history

An historical analysis is made of the word and of the concept of 'dementia' before the nineteenth century. With regard to the word, it is shown that it had legal and medical meanings and that, while the former developed during the seventeenth century, the latter did so only during the eighteenth century (earlier than psychiatric historians have suggested). As evidence for the latter point, rare historical material on 'Démence' from the first edition of the Encyclopédie Française is presented for the first time in English. It is also shown that the legal meaning was finally enshrined in the 'Code Napoléon'. With regards to the concept of dementia, it is shown that it took final shape in the work of Willis, Hartley and Cullen in whose view it was made to include terminal states of behavioural incompetence due to severe failure of almost any mental function. During this period, dementia was not yet associated with a particular age group nor was specifically defined in terms of cognitive deficit. The origins of the 'cognitive' paradigm of dementia and of the clinical boundaries of the future concept of dementia are briefly outlined.

Assessing dementia. Part I: Difficulties, definitions and differential diagnosis

Despite the pressures of an increasingly ageing population and an ever increasing scientific knowledge, the clinical characteristics of dementia remain poorly defined. This relative lack of clarity in clinical understanding has led to diverse diagnostic problems, including those of mistaken diagnosis as well as over- and under-diagnosis in different settings. This paper focuses on the syndromal and aetiological diagnosis of dementia by outlining current clinical definitions, considering differential diagnosis in detail and reviewing characteristics of common dementing disorders. The past emphasis on a search for treatable causes, the reliance on laboratory investigations and the concept of subcortical dementia are all questioned. Aspects of evaluation that are stressed include the value of brief objective cognitive testing, a knowledge of normal age-related cognitive changes, flexible criteria for Alzheimer's disease and a comprehensive individualised evaluation of the person. Broader assessment issues will be dealt with in a second paper.

Organic solvents and presenile dementia: a case referent study using death certificates

Occupational exposure to organic solvents has been implicated in the development of "presenile dementia" in several studies. The death certificates of all men aged under 65 dying in England and Wales bearing presenile dementia as cause of death were collected for the years 1970-9 (n = 557): control death certificates were obtained, matched for age and sex. No significant differences were found between the groups as regards estimated occupational exposure to either organic solvents or lead.

Some calculations on the prevalence of dementia in Canada

The epidemiology of dementia in Canada is not known. However, we report figures on the frequency of dementia in institutions in Ontario based upon the use of a multidimensional observation scale for the assessment of the elderly. These findings on institutionalized patients can be extrapolated to the whole elderly population, but the procedure is clearly too conservative by comparison with findings in other countries and in the light of the known occurrence of numbers of demented patients outside institutions. Ratios in different studies for the numbers of patients with dementia outside institutions and within institutions range from 1:1 to 6:1. Using a ratio of 2:1 and applying it to age specific population figures, a prevalence of dementia in Canada of 222,324 for those over 65 is obtained with a rate of 9.4% in that age group. When the figures projected in this way are compared with five epidemiological studies for the rate of dementia elsewhere, the Canadian figure which we have obtained ranks fourth out of six. This estimate provides potential figures on which to base the planning of services, provided that the inferential nature of the estimates is fully recognized.

Use of the dexamethasone suppression test with depressed and demented elderly

Although some researchers have suggested that the dexamethasone suppression test (DST) may be useful in differentiating between major depression and dementia in the elderly, recent reports of abnormal DST results in nondepressed, demented elderly have questioned the validity of the test in this population. This study compared the frequency of abnormal DST results in three groups of elderly inpatients: depressed/not demented; demented/not depressed; and depressed and demented. Two geropsychiatrists independently evaluated 33 patients for symptoms of depression and/or dementia and then assigned each patient to one of the three groups. Subjects in the demented/not depressed group had a significantly larger proportion of abnormal DSTs (P less than .01), and the mean postdexamethasone, 4 PM blood cortisol level of the demented/not depressed group was significantly greater than the means of the other two groups (P less than .005). In this sample, the DST was more likely to identify dementia than depression. Until further investigations clarify the parameters of DST use in the elderly, the diagnosis of depression and dementia should continue to be determined by sensitive interpretation of clinical findings, history, and other diagnostic tests.

The cholinergic neurotransmitter system in human memory and dementia: a review

The present paper reviews three types of evidence implicating the role of acetylcholine in human memory and dementia: (1) neuropathological evidence that the cholinergic transmitter system is depleted in Alzheimer-type dementia; (2) psychopharmacological studies that have employed “cholinergic blockade” as a model of cholinergic depletion; and (3) clinical studies of cholinergic “replacement” therapy in Alzheimer-type dementia. The evidence that the cholinergic system is depleted in Alzheimer-type dementia has been complemented by the finding that cholinergic blockade in healthy subjects causes a substantial learning (or “acquisition”) deficit in episodic memory. The overall results of studies of replacement therapy have generally been disappointing, but a few have reported benefits in recall and recognition tests. The role of the cholinergic system in many aspects of memory remains to be elucidated; but it seems unlikely that cholinergic depletion accounts for all aspects of the memory disorder in Alzheimer-type dementia, and possibly the depletions of other neurotransmitters also contribute to the memory impairment.

Cognitive impairment in late-life depression: clinical correlates and treatment implications

Elderly depressed inpatients with high vs. low scores on a quantitative mental status examination (the Mini-Mental State (MMS)) were compared with regard to demographic and clinical characteristics, treatment and short-term response, and functional status at 2-year follow-up. Low-MMS patients were less well educated and more likely to be delusional, anxious, and globally impaired than high-MMS patients. The two groups responded equally well to treatment, but the low-MMS group required a lengthier hospital stay and greater use of neuroleptic medications. The two groups also had similar long-term outcomes, although greater attrition was observed among cognitively impaired subjects.

The memory deficits in Alzheimer-type dementia: a review

This review is an account of recent experimental studies of memory deficits at the early stages of Alzheimer-type dementia, evaluating these studies in relation to current theories of memory functioning in humans. Whilst memory deficits are found to be widespread, some aspects are more resilient to impairment than others. For example, the processes associated with articulatory rehearsal in working memory are unimpaired despite a reduction in performance on most tests of primary memory. The “implicit” aspects of secondary memory appear to remain unimpaired, in contrast to a marked decline in “explicit” or “episodic” memory. In addition, there is evidence that the rate of forgetting from secondary memory is normal. Some aspects of episodic and semantic memory are found to be impaired as a consequence of a decline in the efficient organisation and processing of verbal material at encoding or retrieval. It is concluded that the deficits share particular features found in organic amnesia, but with additional deficits which relate to impairments in other domains of functioning.