Objectives-The diagnosis of Alzheimer's disease (AD) is now reliant on the use of NINCDS-ADRDA criteria. Other diseases causing dementia are being increasingly recognised-for example, frontotemporal dementia (FTD). Historically, these disorders have not been clearly demarcated from AD. This study assesses the capability of the NINCDS-ADRDA criteria to accurately distinguish AD from FTD in a series of pathologically proved cases.Methods-The case records of 56 patients (30 with AD, 26 with FTD) who had undergone neuropsychological evaluation, brain imaging, and ultimately postmortem, were assessed in terms of whether at initial diagnosis the NINCDS-ADRDA criteria were successful in diagnosing those patients who had AD and excluding those who did not.Results-(1) The overall sensitivity of the NINCDS-ADRDA criteria in diagnosing "probable" AD from 56 patients with cortical dementia (AD and FTD) was 0.93. However, the specificity was only 0.23; most patients with FTD also fulfilled NINCDS-ADRDA criteria for AD. (2) Cognitive deficits in the realms of orientation and praxis significantly increased the odds of a patient having AD compared with FTD, whereas deficits in problem solving significantly decreased the odds. Neuropsychological impairments in the domains of attention, language, perception, and memory as defined in the NINCDS-ADRDA statement did not contribute to the clinical differentiation of AD and FTD.Conclusion-NINCDS-ADRDA criteria fail accurately to differentiate AD from FTD. Suggestions to improve the diagnostic specificity of the current criteria are made.

BACKGROUND AND PURPOSE:MR imaging is a sensitive diagnostic tool and paraclinical marker of disease activity and prognosis in multiple sclerosis (MS), yet the role of MR imaging of MS is controversial. The aim of this study was to describe the relationship between cognitive function and MS lesion size and position, as shown on comparative images from conventional spin-echo (CSE) and fast fluid-attenuated inversion-recovery (fast FLAIR) MR studies.METHODS:CSE and fast FLAIR sequences consisted of 40 noncontiguous, 3-mm-thick axial sections matched for geometric position in 18 patients with relapsing-remitting MS. Lesions were scored for size, anatomic position, and their comparative appearance on CSE and fast FLAIR images. The neuropsychological assessment tested general psychological performance, memory, and frontal lobe executive function.RESULTS:Fast FLAIR images showed significantly more small (146 versus six) and medium-sized (18 versus four) juxtacortical lesions than did CSE sequences. Small juxtacortical lesions displayed only on fast FLAIR images had a distinctive appearance, suggestive of small areas of perivascular inflammation. The number of these lesions corresponded to reduced performance on the fifth and delayed trials of the Rey Auditory Verbal Learning memory function test.CONCLUSION:Fast FLAIR images show small lesions at the juxtacortical boundary that are not seen on CSE studies. The presence of such lesions correlates with impaired retention of information in memory tasks, which is characteristic of cognitive problems in patients with MS.

OBJECTIVES To provide the clinician with a guide to the clinical utility of 99mTc-HMPAO single photon emission computed tomography (SPECT) and to the interpretation of specific test results in the differential diagnosis of dementia. METHODS Three hundred and sixty three patients with dementia were studied prospectively for a median three (range 1–6) years and classified into disease groups on the basis of established clinical criteria. The degree to which different patterns of cerebral blood flow (CBF) abnormality found on99mTc-HMPAO SPECT imaging at the time of initial patient presentation modified clinical diagnoses was determined by calculating the likelihood ratios for pairwise disease group comparisons. The optimal clinical usage of 99mTc-HMPAO SPECT was determined by calculating the percentage of significant test results for each pairwise disease group comparison. RESULTS Bilateral posterior CBF abnormality was found to significantly increase the odds of a patient having Alzheimer’s disease as opposed to vascular dementia or frontotemporal dementia. Bilateral anterior CBF abnormality significantly increased the odds of a patient having frontotemporal dementia as opposed to Alzheimer’s disease, vascular dementia, or Lewy body disease. “Patchy” CBF changes significantly increased the odds of a patient having vascular dementia as opposed to Alzheimer’s disease. Unilateral anterior, unilateral anterior plus unilateral posterior, and generalised CBF abnormality failed to contribute to the differentiation of any of these forms of dementia. CONCLUSIONS 99mTc-HMPAO SPECT was found to be most useful in distinguishing Alzheimer’s disease from vascular dementia and fronto temporal dementia, and least useful in differentiating between Alzheimer’s disease and Lewy body disease, and between vascular dementia, frontotemporal dementia, and progressive aphasia. It is suggested that CBF SPECT should be used selectively and as an adjunct to clinical evaluation and CT.

This paper considers the different statistics that can be derived from studies on the value of diagnostic tests. Well-accepted quantities, such as sensitivity and specificity, are reviewed and the Value of the likelihood ratio in communicating particular test results is highlighted. A new quantity, the 'diagnostic value index', is proposed and various examples of its application in nuclear medicine studies are presented. This new index is based on a weighted average of the likelihood ratios for all possible outcomes of the test, the average being weighted according to how frequently a particular outcome occurs. This index provides an objective and quantitative means of comparing the diagnostic value of different tests, or of comparing the value of a given test in different patient groups. It is hoped that this will be a useful aid to clinical decision-making concerning referrals for diagnostic tests. ((C) 1998 Lippincott Williams & Wilkins).

Subcortical vascular disease in elderly patients with treatment resistant depression Failure to respond to treatment is an impor- tant and common clinical problem in the management of depressed patients.'In recent years, evidence has emerged to sug- gest that treatment resistance in elderly patients might, at least in part, reflect the presence of underlying cerebral pathology.2It is important, therefore, to consider this possibility before embarking on more vigor- ous treatments such as electroconvulsive therapy.This study reports the neuropsy- chological, neurological, and neuroimaging findings in patients with treatment resistant depression referred to a neurological centre for evaluation of possible underlying cere- bral pathology.The aim was to ascertain the nature of clinical and neuroimaging findings in such patients, and thereby identify those features that might contribute to the recog- nition of cerebral pathology in elderly patients with treatment resistant depression.The study group comprised 14 consecu- tive patients with treatment resistant depres- sion referred to the cerebral function unit at Manchester Royal Infirmary over a three year period.All patients fulfilled DSM III R 1987 criteria for major depressive illness, and all had been treated with at least one type of antidepressant medication for at least three months without clinical benefit.All patients were referred by a consultant psy- chiatrist, and were suspected of having underlying cerebral pathology.The mean age of the patients (four men, 10 women) was 68 (SD 7-9, range 58-84) years.Eight patients were hypertensive, two had non- insulin dependent diabetes mellitus, and nine were cigarette smokers.Two had a his- tory of cerebrovascular disease in a first degree relative.Nine had a history of depressive illness.All patients were exam- ined by a consultant neurologist and a neu- ropsychologist.Profiling of cognitive deficits was obtained using a test instrument developed in this centre.4Brain CT or MRI was performed on all patients, and scans were evaluated by a consultant neuroradiologist.

Lloyd, J. J.; Talbot, P. R.; Snowden, J. S.; Neary, D.; Testa, H. J. Author Information

The purpose of this study was to investigate patterns of 99mTc-HMPAO single-photon emission computed tomography (SPECT) abnormality in Lewy body disease (LBD) and to compare findings with those encountered in Alzheimer's disease (AD). The study group comprised 20 consecutive patient referrals fulfilling clinical criteria for LBD. All patients had fluctuating cognitive impairment and 'subcortical' dysfunction with or without perceptuospatial and/or linguistic impairment. Six patients had asymmetrical signs of parkinsonism (three left-sided and three right-sided), and 14 patients had symmetrical features of extrapyramidal involvement. 99mTc-HMPAO SPECT imaging was performed on LBD patients and findings compared with those of 57 patients with 'probable' AD and 11 normal age-matched controls. Within the LBD and AD groups, patterns of cortical and subcortical blood-flow abnormality were compared with patterns of cognitive and neurological breakdown. LBD was associated with bilateral posterior cortical blood flow abnormality, a pattern strikingly similar to that found in AD. Within the LBD group, cortical blood-flow abnormality was found to reflect patterns of neurological dysfunction (parkinsonism) indicative of subcortical involvement. In contrast, cortical blood-flow changes did not reflect patterns of neuropsychological impairment suggestive of cortical dysfunction. Within the AD group, cortical blood-flow changes were mirrored by the pattern of neuropsychological impairment. Findings support the notion that cortical blood-flow abnormality in LBD might reflect a combination of direct cortical pathology and cortical deafferentation secondary to subcortical Lewy body pathology. It would appear that 99mTc-HMPAO SPECT imaging is of limited value in the clinical differentiation of LBD and AD.

Frontal lobe dementia (FLD) (syn. frontotemporal dementia and dementia of frontal type) is a generic term that describes a clinical syndrome in which patients manifest a profound breakdown in personality and social conduct, together with adynamic spontaneous speech, culminating in mutism. This pattern of cognitive impairment implicates bilateral frontal lobe dysfunction, an assumption supported by functional neuroimaging findings of anterior cerebral abnormality.Patients with FLD can go on to develop motor neuron disease (FLD-MND), although the clinical features of MND may accompany or occasionally precede the onset of dementia. The emergence of MND is responsible for death within 3 years of onset. Frontotemporal lobar pathology in FLD-MND is characterized by loss of large cortical neurons, spongiform change and mild astrocytic gliosis. Ubiquitinated (but not tau-positive) inclusions are present within the frontal cortex. There is severe nigral cell loss (without Lewy bodies), and marked hypoglossal and spinal motor neuron degeneration, together with ubiquitinated (but not tau-positive) inclusions within the spinal neurons. Some authors suggest that FLD-MND is a separate disease entity, whereas others suggest it represents an interface between FLD and ''classic'' (non-dementing) motor neuron disease (CMND). An association with CMND is supported by findings in these patients of failure in tasks sensitive to ''frontal lobe'' dysfunction, and patterns of functional neuroimaging abnormality which are identical in distribution, but less severe than those encountered in FLD-MND. However, the nosological status of FLD-MND remains enigmatic in the absence of defined pathological and molecular markers.

Varma, A. R.; Talbot, P. R.; Snowden, J. S.; Lloyd, J. J.; Neary, D.; Testa, H. J. Author Information

This review critically evaluates the current role of single photon emission tomography (SPET) imaging in the clinical management of patients with dementia. The classification of the dementias is discussed and the clinical and pathological features of the various dementing illnesses are described. Typical appearances on cerebral blood flow imaging are presented for each of the conditions, together with the findings on D2 dopaminergic receptor and muscarinic receptor imaging where this is relevant. The review concludes with a section on the clinical value of SPET imaging in dementia. SPET imaging can make a valuable contribution to the accurate clinical differentiation of dementia, providing findings are interpreted in the light of neurological evaluation and structural imaging. The possible future role of SPET imaging in the prediction and evaluation of response to future therapeutic agents is discussed.

Talbot, P. R.; Lloyd, J. J.; Snowden, J. S.; Neary, D.; Testa, H. J. Author Information

The purpose of this study was to examine the possible association between "classic" motor neuron disease (cMND) and frontotemporal dementia (FTD), using neuropsychological evaluation and single photon emission computed tomography (SPECT). Psychological tests assessing language, perceptuospatial, memory, and "frontal lobe" functions were given to patients with cMND and test scores were compared with those of normal control subjects. 99mTc-HMPAO SPECT was performed on patients with cMND, FTD and motor neuron disease (FTD/MND), FTD alone, and normal control subjects. Regional cerebral blood flow indices (rCBFi) were determined in 36 cortical regions, and differences between grouped rCBFi data were investigated by canonical discriminant analysis. There were significant group differences in the scores of picture sequencing and token tests in patients with cMND compared with normal controls. Regional CBFi data showed frontal and anterior temporal reductions in patients with cMND compared with normal controls. A similar pattern of SPECT abnormality was seen in patients with FTD/MND and FTD alone, but to a more pronounced degree than in patients with cMND. Neuropsychological and SPECT findings in cMND, FTD/MND, and FTD showed a common pattern of cerebral involvement, most pronounced in the second two conditions. It is suggested that cMND, FTD/MND, and FTD represent a clinical range of a pathological continuum.

Talbot, P. R.; Snowden, J. S.; Lloyd, J. J.; Neary, D.; Testa, H. J. Author Information

Talbot, P. R.; Goulding, P. J.; Lloyd, J. J.; Neary, D.; Testa, H. J. Author Information

Talbot, P. R.; Lloyd, J. J.; Snowden, J. S.; Neary, D.; Testa, H. J. Author Information

Departments of Neurology and Nuclear Medicine, Manchester Royal Infirmary, Oxford Road, Manchester, UK