The role of routine laboratory studies and neuroimaging in the diagnosis of dementia: a clinicopathological study

OBJECTIVE: To determine the neuropathological diagnoses of longitudinally followed patients with potentially reversible causes of dementia and to examine the results of the "dementia work-up," especially neuroimaging, by comparison with the pathological diagnosis. DESIGN: A neuropathologic series of 61 consecutive patients, with review of clinical, laboratory, neuroimaging, and pathological results. RESULTS: Of the 61 patients, forty-eight (79%) had a clinical diagnosis of probable or possible Alzheimer's disease (AD). Compared with the pathological diagnosis, the sensitivity and specificity of the clinical diagnosis of AD were 96% and 79%, respectively. Of the 61 patients, 9 had abnormal laboratory tests, the correction of which did not improve the subsequent course. These patients were found to have AD8 and frontotemporal dementia on pathology. In two patients, neuroimaging was helpful in the clinical diagnoses of frontotemporal dementia and progressive supranuclear palsy (PSP). Neuroimaging revealed cerebrovascular disease in 18 patients, only two of whom were suspected clinically. Pathology confirmed AD in 17 and PSP in 1 of these patients. Sensitivity and specificity for the clinical diagnosis of cerebrovascular disease in comparison with pathology were 6% and 98%, respectively. With the added information from neuroimaging, that sensitivity increased to 59% and specificity decreased to 81%. CONCLUSIONS: All cases with abnormal laboratory or neuroimaging results had AD or some other neurodegenerative disease on pathology. The "dementia work-up" did not reveal any reversible causes for dementia in this group of patients. Neuroimaging may have a role, especially in the diagnosis of possible AD with concomitant cerebrovascular disease.     

Vascular Cognitive Impairment and Dementia: JACC Scientific Expert Panel

Cognitive impairment associated with aging has emerged as one of the major public health challenges of our time. Although Alzheimer’s disease is the leading cause of clinically diagnosed dementia in Western countries, cognitive impairment of vascular etiology is the second most common cause and may be the predominant one in East Asia. Furthermore, alterations of the large and small cerebral vasculature, including those affecting the microcirculation of the subcortical white matter, are key contributors to the clinical expression of cognitive dysfunction caused by other pathologies, including Alzheimer’s disease. This scientific expert panel provides a critical appraisal of the epidemiology, pathobiology, neuropathology, and neuroimaging of vascular cognitive impairment and dementia, and of current diagnostic and therapeutic approaches. Unresolved issues are also examined to shed light on new basic and clinical research avenues that may lead to mitigating one of the most devastating human conditions.     

Advances in neuroimaging for HIV-1 associated neurological dysfunction: clues to the diagnosis, pathogenesis and therapeutic monitoring

Persons with advanced human immunodeficiency virus type one (HIV-1) infection seek medical advice for a wide range of neurological disorders including, but not limited to, peripheral neuropathy, toxoplasmosis, cryptococcal meningitis, cytomegalovirus retinitis progressive multifocal leukoencephalopathy, lymphoma and dementia. The diagnosis of HIV-1-associated dementia (HAD) induced as a direct consequence of HIV infection of the brain comes commonly by exclusion. Diagnostic decisions can often be clouded by concomitant depression, motor impairments, and lethargy that follow debilitating immune suppression and weight loss. Indeed, cognitive, motor and behavior abnormalities underlie a variety of neurological dysfunctions associated with advanced HIV-1 infection. Thus, even combinations of clinical, laboratory and neuroimaging tests [for example, magnetic resonance imaging (MRI), computed tomography (CT), single photon emission computed tomography (SPECT) and positron emission tomography (PET)] often fail to provide conclusive diagnostic information. Nonetheless, the recent development of quantitative MR spectroscopic imaging has improved diagnostic possibilities for HAD. We are pleased to discuss these developments as well as taking a forward look into what will soon be made available to improve neuroimaging diagnostic precision. New MR and SPECT testing are being developed in our laboratories and elsewhere both for animal model systems and in humans with HIV-1 disease. Such tests can facilitate dynamic measures of HIV-1 neuropathogenesis providing information for disease events that even 2 years ago were unattainable.     

Systematic review of clinical prediction rules for neuroimaging in the evaluation of dementia

BACKGROUND: Clinical practice guidelines for dementia do not recommend routine neuroimaging but vary in their recommended clinical prediction rules to identify patients who should undergo neuroimaging for potentially reversible causes of dementia. METHODS: Using a MEDLINE search supplemented by other strategies, we identified studies from January 1, 1983, through December 31, 1998, that evaluated the diagnostic performance of a clinical prediction rule. We calculated the sensitivity and specificity of each rule, then evaluated their diagnostic performance in a hypothetical cohort of 1000 patients with dementia, varying the prevalence of potentially reversible dementia from 1% to 15%. RESULTS: We identified 7 studies that evaluated at least 1 of 6 different clinical prediction rules. Only one rule consistently had high sensitivity (>85%) across all studies; none consistently had high specificity (>85%). Six of the 7 studies included less than 15 cases of potentially reversible dementia; thus the sensitivity and specificity for each rule had relatively wide confidence intervals. At a 5% prevalence of potentially reversible dementia, all rules had low positive predictive value (<15%) in our hypothetical cohort. Depending on the rule, our analysis predicts 6 to 44 of the 50 patients with potentially reversible dementia (5% prevalence in cohort of 1000 patients) would not undergo imaging. CONCLUSIONS: There is considerable uncertainty in the evidence underlying clinical prediction rules to identify which patients with dementia should undergo neuroimaging. Application of these rules may miss patients with potentially reversible causes of dementia.     

Dementia, diagnostic disclosure, and self-reported health status

OBJECTIVES: To investigate the general awareness of cognitive impairment in persons with documented dementia, evaluate the subject's recall of a diagnostic disclosure from a physician and their recollection of the discussion, and determine whether this awareness of cognitive impairment or the recall of diagnostic disclosure is associated with poorer self‐rated health scores. DESIGN: Secondary data analysis. SETTING: Three university‐based clinical referral sites for dementia illnesses. PARTICIPANTS: Convenience sample of 149 patients with a diagnosis of dementia. MEASUREMENTS: Bivariate and logistic regression models with the outcome variables of patient self‐report of memory problems, patient report of being told about memory problems by a physician, and self‐reported health scores. RESULTS: Ninety‐six of 149 (64.4%) subjects reported that they had memory problems, and this report was independently associated with younger age (P=.01) and higher Mini‐Mental State Examination score (P=.02). Thirty‐nine (26.2%) subjects reported being told by a physician about a diagnosis of dementia or memory problems. This recall was associated with younger age (P<.001), male sex (P=.04), and higher education level (P=.02). African Americans reported poorer self‐rated health scores (odds ratio (OR)=2.4, 95% confidence interval (CI)=1.1–5.1). Persons who reported being told by a physician of a diagnosis of dementia were more likely to report poorer self‐rated health (OR=2.5, 95% CI 1.1–5.5). CONCLUSION: Further research is needed to elucidate the relationship between self‐rated health and dementia specifically focusing on the potentially negative effects of diagnostic disclosure on self‐rated health, further identification of factors that contribute to self‐rated health in persons with dementia, and the prognostic value of self‐rated health for persons with dementia.     

Auswirkungen der erweiterten klinischen Diagnostik auf das Diagnosespektrum einer Gedächtnisambulanz

OBJECTIVES: In an outpatient memory clinic, the methods of extended clinical diagnostics pertaining to imaging and neuropsychology were changed but the modus of assignment to the clinic remained unchanged at different times. Expected changes in the diagnostic spectrum can be attributed to the changed diagnostics. Consistent with reports from the literature regarding the consequences of such changes, the associated costs have to be taken into consideration as well. METHODS: The clinical final diagnoses of 174 patients referred in 2000/2001 for the diagnostics and differential diagnostics of dementia ("current population") were compared with those of 169 patients who visited the same outpatient clinic in 1998/1999 ("former population"). The diagnostic spectra of the two populations were compared. The diagnoses were differentiated in "no dementia" (XD), "neurodegenerative dementia" (ND), "vascular dementia" (VD), and "dementia of the mixed type" (MIXD). For all patients, the same clinical diagnostic criteria (ICD-10) and laboratory tests were implemented. Only the neuroradiological and neuropsychological methods changed from 1998/1999 to 2000/2001: The current population was examined with MRI instead of CT and underwent an expanded neuropsychological test battery with additional power and speed tests. RESULTS: The diagnoses of the two populations differed significantly in their frequency distribution. A dementia was excluded in 51.1% of the "current" patients vs 19.5% of the "former" patients. The frequencies of the dementia diagnoses were significantly different for the diagnoses ND (29.9 vs 47.9%) and MIXD (1.1 vs 7.7%), but not for VD (13.2 vs 12.4%). Beside other independent modalities, the improvement of imaging with MRI is discussed as recording atrophy size and vascular lesions better than CT. The improvement of the neuropsychological test battery containing additional speed tests is discussed as being able to differentiate even minimal cognitive disturbances. CONCLUSION: Using optimized imaging and neuropsychological methods, the diagnostic spectrum of an outpatient memory clinic changed. The clinical diagnosis was improved by the more sensitive, extended clinical diagnostics. Through optimized differential diagnostic allocation and the exclusion of dementia, expenses can be reduced by early and indication-related medication and by the resulting delay of institutionalized care.     

Two way push videoenteroscopy in investigation of small bowel disease

AIMS: To evaluate the diagnostic yield and safety of a new push type videoenteroscope (PVE) for diagnosis of small bowel disease. METHODS: Three hundred and thirteen patients were referred for one or two way PVE from December 1993 to June 1996. Indications for PVE were: an unexplained iron deficiency anaemia with or without clinically evident gastrointestinal bleeding; or a complementary investigation for suspected small bowel disease, after a small bowel barium follow through (SBBFT) considered as normal or abnormal, but without a definite diagnosis. RESULTS: A jejunoscopy and a retrograde ileoscopy were carried out in 306 and 234 patients, respectively. In patients with isolated anaemia (n = 131) and those with clinically evident gastrointestinal bleeding associated anaemia (n = 72), PVE provided a diagnosis in 26 (19.8%) and 22 (30.5%) cases, respectively. Lesions found were located in the jejunoileum in 30 (14.7%) patients and in the gastroduodenum or the colon in 18 (8.8%) patients--that is, within the reach of the conventional gastroscope/colonoscope. In patients with normal (n = 54) or abnormal (n = 56) SBBFT, PVE provided a diagnosis in 17 (31%) and 27 (48%) cases, respectively. In 25% of cases, the abnormal appearance of SBBFT was not confirmed. The site of the radiological abnormality was not reached in 27% of cases. Lesions were located at the jejunum and the ileum in 59 (64%) and 33 (36%) cases, respectively. CONCLUSIONS: PVE is useful in around 30% of cases of unexplained anaemia or after an SBBFT which failed to provide an accurate aetiological diagnosis. Use of retrograde videoenteroscopy increases diagnostic yield by one third.     

Value of neuropsychological tests, neuroimaging, and biomarkers for diagnosing Alzheimer's disease in younger and older age cohorts

OBJECTIVES: To examine the influence of age on the value of four techniques for diagnosing Alzheimer's disease (AD). DESIGN: Observational cohort study. SETTING: Alzheimer's Disease Neuroimaging Initiative. PARTICIPANTS: Individuals with mild cognitive impairment (MCI; n=179), individuals with AD (n=91), and normal controls (n=105). MEASUREMENTS: Neuropsychological tests, structural magnetic resonance imaging (MRI), amyloid‐beta and tau in cerebrospinal fluid (CSF), and [18F]fluorodeoxyglucose positron emission tomography (FDG‐PET) for the diagnosis of MCI or AD. MCI was defined according to subjective memory complaints corroborated by an informant and an abnormal score on the delayed paragraph recall subtest of the Wechsler Memory Scale–Revised, a Mini‐Mental State Examination score greater than 23, and a Clinical Dementia Rating score of 0.5. Participants with AD satisfied National Institute of Neurological and Communicative Diseases and Stroke/Alzheimer's Disease and Related Disorders Association criteria of probable AD. RESULTS: Neuropsychological tests and MRI were the most informative techniques, with 84% and 82% correct classifications, respectively, and areas under the receiver operating characteristic curve (AUCs) of 0.93 (90% confidence interval (CI)=0.91–0.95) and 0.88 (90% CI=0.85–0.91). FDG‐PET and CSF assessments had 76% and 73% correct classifications, respectively, (AUC=0.77, 90% CI=0.71–0.83; AUC=0.77, 90% CI=0.73–0.82). These figures increased slightly when the techniques were combined. All analyses were repeated for the younger (<75) and older (≥75) halves of the sample. FDG‐PET and CSF assessment were substantially less informative in the older cohort, and they did not add diagnostic information when all techniques were combined. CONCLUSIONS: Structural MRI and neuropsychological assessment are diagnostic methods of first choice if AD is suspected. CSF and FDG‐PET add little to these diagnostic techniques, especially in older adults.     

Can dementia be diagnosed during hospitalisation?

IntroductionAcute hospitalisation can be an opportunity to diagnose dementia if it can be guaranteed that confounding factors are taken into account.ObjectiveTo study the validity of systematic criteria for the detection of cognitive impairment and of a standardised diagnostic protocol of dementia in elderly patients hospitalised in a geriatric service.MethodsPatients were included if they met any of the following criteria: a) previous score on the Red Cross Mental Scale (RCMS) ≥ 2, b) Pfeiffer Questionnaire score ≥ 5 errors and/or c) presence of delirium (Confusion Assessment Method criteria). A geriatrician conducted a cognitive history and physical examination and the following diagnostic protocol was applied: DSM-IV criteria for dementia, Mini Mental State Examination, Clock Drawing Test, Informant Questionnaire, Clinical Dementia Rating Scale, Pfeffer Scale of Instrumental Activities and Laboratory and neuroimaging tests. Each diagnosis was confirmed by another independent geriatrician.ResultsSeven hundred and fifty-five patients were hospitalised, of which 156 (21%) met the inclusion criteria. The study could be completed during hospitalization in 114 patients (73%). The definitive diagnosis was Alzheimer's disease or mixed dementia in 63 cases (40%), vascular dementia in 17 (11%), mild cognitive impairment in 6 (4%) and delirium without previous decline in 28 (18%). Treatment recommendations were given in all cases.ConclusionsApplication of systematic detection criteria and a standardised diagnostic protocol made it possible to discover unknown cognitive problems in one of every five hospitalised elders and to diagnose 73% of them. Most of the diagnosis were for established dementia.     

The association between vascular risk factor-mediating medications and cognition and dementia diagnosis in a community-based sample of African-Americans

OBJECTIVE: To determine the association between medications that ameliorate vascular risk factors and the prevalence of cognitive impairment and dementia in an older African-American population. DESIGN: A community-based survey to identify subjects with and without evidence of cognitive impairment and subsequent diagnostic evaluation of a stratified sample of these subjects using formal diagnostic criteria for dementia and Alzheimer's disease (AD). SETTING: Urban neighborhoods in Indianapolis, Indiana. SUBJECTS: A random sample of 2,212 African-American adults aged 65 years and older residing in 29 contiguous census tracts. MEASUREMENTS: Subjects' scores on the Community Screening Instrument for Dementia (CSID), formal diagnostic and clinical assessments for dementia, current medication use and history of medical illnesses, both self-report and, where possible, from an informant. Four outcome measures were defined by the following criteria: (1) cognitive impairment as defined by the subject's performance on the CSID cognitive scale; (2) cognitive/ functional impairment as defined by the total CSID score that included a relative's assessment of the subject's functional abilities; (3) dementia as defined by explicit diagnostic criteria; and (4) possible or probable Alzheimer's Disease as defined by explicit criteria. RESULTS: The vascular risk factor mediating medications, when analyzed together, were associated with a significantly decreased risk of diagnosis of cognitive impairment after controlling for age, education, and stroke (OR 0.73, P = .01) and also a significantly decreased risk of cognitive/functional impairment (OR 0.66, P = .02). Antihypertensive agents, excluding centrally acting sympatholytic drugs were associated with a significantly reduced risk of diagnosis of cognitive impairment (OR 0.56, P < .01) and cognitive/functional impairment (OR 0.64, P = .01). Centrally acting sympatholytic agents were associated with an increased risk of diagnosis of cognitive impairment (OR 2.24, P < .01). There was a trend toward protection from a diagnosis of AD and dementia for the vascular risk factor mediating medications and for the antihypertensive medication, but this did not reach significant levels. CONCLUSIONS: These data suggest that the use of medications to ameliorate vascular risk factors, particularly antihypertensive medication, may also be useful in reducing the risk of cognitive impairment in older subjects. However, they also suggest that physicians should be cautious in prescribing antihypertensive drugs with centrally acting sympatholytic properties to older subjects.     

Age- and education-specific reference values for the cognitive test of the SIDAM (Structured interview for the diagnosis of dementia of the Alzheimer type,multi-infarct dementia and dementias of other etiology according to ICD-10 and DSM-IV)

The SIDAM (Structured Interview for the diagnosis of Dementia of the Alzheimer type, Multi-infarct dementia and dementias of other etiology according to ICD-10 and DSM-IV) is a standardized interview for the diagnosis of dementia. It can also be used as a screening instrument for the diagnosis of different syndromes of dementia and mild cognitive impairment. At present there is no age- or education-specific standardization. This report presents age- and education-specific norms for the cognitive assessment of the SIDAM, obtained in a population-based sample of elderly people aged 75 and over (n=1001).     

Diagnosing cognitive impairment and dementia in primary health care -- a more active approach is needed

OBJECTIVE: to determine the documentation rate of dementia in primary health care, the clinical characteristics of patients with documented and undocumented dementia, and the diagnostic evaluations made in cognitive impairment. DESIGN: cross-sectional population-based study with a retrospective review of medical history. SETTING: primary health care in the municipality of Lieto, Southwestern Finland. SUBJECTS: all the inhabitants aged 64 and over in Lieto. Participation rate 82%, numbers = 1260. MEASUREMENTS: assessment of dementia according to DSM-IV criteria, and severity according to Clinical Dementia Rating. Possible documentation of dementia and evaluations done were reviewed from primary health care medical records. RESULTS: 112 patients with dementia were found. The sensitivity of the general practitioners' judgment of dementia was 48.2% and the specificity 99.6%. The documentation rate of dementia was 73% in severe, 46% in moderate and 33% in mild dementia. A greater proportion of the patients with undocumented dementia were male (P = 0.003), lived at home (P = 0.003), coped better with the instrumental activities of daily living (P = 0.006), had more depression (P = 0.029) and milder dementia (P = 0.005) than patients with documented dementia. Thyroid stimulating hormone was measured in 51% of the patients with suspected memory impairment or dementia, B12 vitamin in 20%, and serum calcium in 18%. Twenty-eight per cent of the patients had been tested for cognitive function, 68% for depressive symptoms, and 88% for social abilities. Forty-two per cent of patients were referred to a specialist, 32% of patients who were over 75 years. CONCLUSIONS: less than half of the patients with dementia had their diagnosis documented in primary care medical records. Documentation increased in more advanced dementia. The diagnostic evaluations for reversible causes of dementia were insufficient in primary care, and they were done at a late phase of cognitive impairment.     

轻度认知损害患者的静息态功能磁共振成像

识别轻度认知损害(mild cognitive impairment,MCI)的意义在于能尽早进行干预并推迟甚至阻止其进展为痴呆.不过,由于受到诊断方法和标准的限制,MCI患者的诊断较为困难.近年来,静息态功能磁共振成像(resting-state functional magnetic resonance imaging,rs-fMRI)作为一种新兴的功能影像学技术得到迅速发展,被广泛应用于MCI的研究,有可能为MCI的诊断提供客观的生物学标记物.文章就rs-fMRI在MCI中的研究进展进行了综述.     

Biomarkers,mild cognitive impairment and early diagnosis of Alzheimer's disease

Elderly people are concerned about changes in their cognitive functioning. Since cholinergic therapies for Alzheimer's disease have been developed and become widely accepted, elderly people have come to visit clinics to seek medical advice about whether such a subtle change in cognitive ability may represent an early manifestation of Alzheimer's disease (AD). If they are likely to develop dementia or AD, they want to receive immediate medical treatment as soon as possible to prevent further loss of cognitive functioning so that they can live independently as long as possible. The first priority in the clinical application of a biomarker is that biomarker should contribute to early diagnosis of dementia. Among such biomarkers, we believe that cerebrospinal fluid markers and functional brain imaging are clinically the most applicable procedures. Since 1993, we have collected 623 cerebrospinal fluid (CSF) samples at The Tohoku University Hospital for evaluation of dementia (age: 42-93). We found that CSF/phospho-tau measures produced the most adequate sensitivity (85.2%) and specificity (85.0%) in the diagnosis of AD as a sole bio-marker. The CSF levels of A beta 1-42 showed a strong positive correlation with the Mini-mental state examination score and brain glucose metabolism by positron emission tomography. The baseline levels of both total-tau and phospho-tau in CSF increased in approximately 70% of patients with mild cognitive impairment who later developed AD, suggesting that pathological change in the brain might start years before dementia becomes clinically manifested. A combined use of CSF-tau and IMP-SPECT improved the predictability of the transition from mild cognitive impairment into AD.     

Glycemia and Levels of Cerebrospinal Fluid Amyloid and Tau in Patients Attending a Memory Clinic

OBJECTIVES: To determine the association between markers of glycemia and cerebrospinal fluid (CSF) amyloid β 1–42 (Aβ42) and tau levels in patients attending a memory clinic. DESIGN: Cross‐sectional study. SETTING: Memory clinic. PARTICIPANTS: Two hundred forty‐five consecutive patients attending a memory clinic. Clinical diagnoses were subjective cognitive complaints (n=91), mild cognitive impairment (n=62), Alzheimer's disease (n=58), and other dementia (n=34). Twenty‐one patients had diabetes mellitus. MEASUREMENTS: Glycosylated hemoglobin (HbA1c); fasting blood glucose levels; and CSF levels of Aβ42, total tau, and p‐tau 181. RESULTS: In regression analyses across the whole study sample adjusted for age, sex, and diagnostic group, there was no relationship between HbA1c or fasting glucose and CSF tau, p‐tau 182, or Aβ42 levels. Stratification for diabetes mellitus did not change the results. CONCLUSION: These observations do not support the hypothesis that the association between dysglycemia and impaired cognitive functioning is mediated through aberrant amyloid or tau metabolism.     

The decreasing prevalence of reversible dementias: an updated meta-analysis

BACKGROUND: In 1988, 2 meta-analyses suggested that the prevalence of reversible dementia was significantly lower than had been previously estimated. It was predicted that further work would indicate an even lower rate. The present study represents an updated meta-analysis of the true prevalence of reversible dementia. METHODS: MEDLINE was searched from 1987 through 2002. References were also gleaned from pertinent articles and relevant textbooks. Data were extracted on the nature and provenance of the studies, dementia etiology, and the proportion of cases that were potentially reversible and reversed. RESULTS: Fifty articles were identified of which 39 met the study criteria, representing 7042 patients of whom 5620 (87.2%) had dementia. Patients were classified according to etiology and, where possible (in 23 [59%] of 39 studies), whether the dementia partially or completely resolved. A much higher proportion of studies than was previously the case were either community-based (31%) or observed subjects from outpatient departments (54%). Alzheimer disease was still the commonest cause of dementia (56.3%) followed by a vascular etiology (20.3%). Conditions requiring neuroimaging made up only 2.2% of cases. Potentially reversible causes were seen in 9%, and only 0.6% of dementia cases actually reversed (0.29% partially, 0.31% fully). CONCLUSIONS: The reported proportion of dementias that reverse is much lower than previously thought. While comorbidity should always be treated for its own sake and in the hope that cognitive decline may at least be delayed, the present findings have significant clinical and economic implications for the workup of dementia.     

Prevalence and severity of gait disorders in Alzheimer's and non-Alzheimer's dementias

OBJECTIVES: To compare the prevalence, severity, and type of gait and balance disorders in Alzheimer's disease (AD), vascular dementia (VaD), Parkinson's disease with dementia (PDD), dementia with Lewy bodies (DLB), Parkinson's disease without dementia (PD), and age-matched controls. DESIGN: Cross-sectional. SETTING: Secondary care clinics in geriatric psychiatry, neurology, and geriatrics. PARTICIPANTS: Two hundred forty-five participants aged 65 and older (AD, n=40; VaD, n=39; PDD, n=46; DLB, n=32; PD, n=46; and controls, n=42). MEASUREMENTS: Prevalence and severity of gait and balance disorders were assessed using the Tinetti gait and balance scale. The types of gait disorders in each diagnostic group were classified using the Nutt et al. classification. RESULTS: Gait and balance disorders were more common with PDD (93%), VaD (79%), and DLB (75%) than with PD (43%) and AD (25%) and in controls (7%). The risk of gait and balance disorder was higher in the non-Alzheimer's dementia groups (VaD, PDD, and DLB) than in the AD group (odds ratio=15 (95% confidence interval=6-37). If a gait disorder was present in mild dementia (Cambridge Examination for Mental Disorders of the Elderly cognitive subsection score >65), this was diagnostic of non-Alzheimer's dementia, with sensitivity of 78% and specificity of 100%. Non-Alzheimer's dementia groups had worse Tinetti gait and balance scores than the AD group (all P<.001). The types of gait disorders discriminated between non-Alzheimer's dementias. CONCLUSION: The findings support the idea that gait and balance assessment may augment the diagnostic evaluation of dementia.     

Does computed tomographic brain imaging have a place in the diagnosis of dementia?

BACKGROUND--Computed tomographic (CT) scanning of the head is an accepted routine in the evaluation of dementia. This study attempted to identify a patient group in which brain imaging adds meaningful data to the clinical picture. METHODS--One hundred patients who met criteria for dementia as defined in the Diagnostic and Statistical Manual of Mental Disorders, Revised Third Edition, underwent computed tomographic imaging. From clinical data alone, 56 of these patients also met the following strict criteria for the diagnosis of probable Alzheimer's disease (PAD): the McKhann criteria for PAD, Diagnostic and Statistical Manual of Mental Disorders, Revised Third Edition, criteria for primary degenerative dementia, a score of less than 4 on the modified Hachinski Ischemia Scale, a normal neurologic examination and symptoms for at least 1 year. RESULTS--In the PAD group, eight scans (14%) had abnormalities other than atrophy; only three (two showing lacunae and one showing infarct) were of possible clinical significance. In the 44 patients not meeting PAD criteria, 23 scans (52%) were abnormal, including 15 with infarcts, two with periventricular lucencies, three showing tumors, and one showing hydrocephalus. CONCLUSIONS--These results support the diagnostic value of computed tomographic scanning in atypical dementia and its limited utility in PAD. The data indicate that clinical guidelines can be developed for the application of CT in the diagnosis of dementia.