WAIS-R short-forms: criterion validity in healthy and clinical samples

Regression equations developed by Crawford, Allan & Jack (1992) to estimate full-length WAIS-R IQs from seven short-forms were evaluated in healthy (N = 153) and neurological (N = 471) cross-validation samples. In the healthy sample the correlations between the short-forms and full-length IQs did not differ significantly from those obtained by Crawford et al. (1992). In the neurological sample the six- and seven-subtest short-forms, proposed by Crawford et al. (1992) and Warrington, James & Maciejewski (1986) respectively, differed from the other short-forms in that they had significantly higher criterion validity coefficients and did not systematically under- or overestimate IQs.

WAIS-R subtest scatter: base-rate data from a healthy UK sample

Base-rate data on subtest scatter for the WAIS-R was obtained from a sample of 200 healthy subjects recruited to match the adult UK population in terms of age, sex and social class distribution. Tables are presented which permit an assessment of the abnormality (i.e. rarity) of an individual's pattern of WAIS-R performance in terms of subtest range and subtest deviations from an individual's subtest mean. Guidance on the appropriate use of the tables is offered and the data are compared with data from the US WAIS-R standardization sample where appropriate. The distinction between reliable and abnormal differences is highlighted.

The WAIS-R(UK): basic psychometric properties in an adult UK sample

The WAIS-R is the most widely used measure of intellectual ability in the UK, despite never having been standardized in this country. The present study examined the psychometric properties of the WAIS-R in a sample of 200 subjects, which was representative of the adult UK population in terms of the distributions of age, sex and social class. The properties of the three IQ scales, i.e. the FSIQ, the VIQ and the PIQ, were found to be very similar to those reported for the US standardization sample: the scores were normally distributed, with means close to the desired value of 100; moreover, the reliabilities of the IQ scales were extremely high and closely matched the US reliabilities. There were also indications, however, that the scales have restricted standard deviations when used in the UK. The reliabilities of the 11 original subtests ranged from moderate to high and the majority were similar to the US reliabilities. However, in addition to evidence of restricted SDs, significant differences (sometimes as much as two-thirds of an SD) were found among the subtest means. These in-built subtest discrepancies could lead to erroneous conclusions about an individual's performance. A conversion table for UK test users is provided to overcome this problem.

Cognitive performance in UK sample of presymptomatic people carrying the gene for Huntington's disease

This paper presents an investigation of cognitive ability in 30 subjects at risk for Huntington's disease. Those shown to be at high or low risk for this disease are compared on a wide range of neuropsychological measures. Results indicate only one significant difference between the two groups; those who carry the gene show a higher level of performance on the Corsi Supraspan task. It is suggested, however, that minimal deficits are apparent in the at risk gene carrying group but that current measures of assessment are not sensitive enough to identify them.

The Mahalanobis Distance index of WAIS-R subtest scatter: psychometric properties in a healthy UK sample

Burgess (1991) has proposed a new index of subtest scatter for the WAIS-R which uses a test statistic, the Mahalanobis Distance (MD). When used with the WAIS-R, MD scores should be distributed as chi square with 11 degrees of freedom. The suitability of the MD index for UK clinical practice was assessed by examining its psychometric properties in a sample of 200 healthy subjects. The sample, which was representative of the adult UK population in terms of age, sex, and social class distribution, was administered a full-length WAIS-R. A goodness-of-fit test revealed that the sample distribution of MD scores did not deviate significantly from the chi square distribution. Furthermore, the percentage of subjects exceeding the critical value for significance at the .05 level (6.5 per cent) corresponded closely to the expected percentage (i.e. 5 per cent). It is concluded that the MD index is suitable for use in UK clinical practice. Demographic characteristics were only weakly related to MD scores which simplifies clinical interpretation.

Frontal lobe impairment in schizophrenia: relationship to intellectual functioning

Schizophrenic subjects (N = 48) and individually matched healthy controls were administered the Verbal Scale of the Wechsler Adult Intelligence Scale (VIQ) and a test of verbal fluency. The verbal fluency and VIQ scores of the schizophrenic subjects were significantly lower than the scores of the control subjects. An additional sample of healthy subjects (N = 144) was used to generate a regression equation for the prediction of verbal fluency scores from Verbal IQ and age. The verbal fluency scores obtained by the schizophrenic subjects were significantly lower than the scores predicted from the regression equation, whereas a significant difference was not obtained in the matched controls. These results provide further evidence of frontal lobe dysfunction in schizophrenia.

Severe hypoglycemia and intelligence in adult patients with insulin-treated diabetes

The IQ scores (WAIS-R) of 100 patients with insulin-treated diabetes (aged 25-52 yr) were compared with those of 100 healthy control subjects who were matched to the diabetic patients for sex, age, education, and social class. The diabetic group had lower WAIS-R performance and verbal IQ scores than the control group (P = 0.017 and P = 0.033, respectively) after controlling for premorbid IQ. The extent of the difference was modest, representing approximately 33% of an SD in IQ. When frequency of severe hypoglycemia was controlled for the difference in performance IQ between the diabetic patient group and the control group was abolished, whereas the difference between the groups in verbal IQ persisted. It is hypothesised that cumulative severe hypoglycemia might be the major factor in the slight performance IQ differences between diabetic patients and control subjects. The origin of the verbal IQ differences, although obscure, might be related to the social impact of the disorder.

Verbal fluency: a NART-based equation for the estimation of premorbid performance

A sample of 142 subjects free of neurological or psychiatric disorder were administered the National Adult Reading Test (NART) and a verbal fluency (VF) test. A highly significant correlation between the NART and VF was obtained indicating that premorbid ability should be taken into account when interpreting VF performance. A regression equation was built to estimate premorbid performance on VF from the NART. A highly significant difference between predicted and obtained VF was obtained in a sample of neurological patients (N = 38). For ease of use, a table converting NART errors to predicted VF scores is presented.

Estimation of premorbid intelligence in schizophrenia

To determine whether the National Adult Reading Test (NART) would provide a valid estimate of premorbid intelligence in schizophrenia, two schizophrenic samples were recruited, one consisting of 35 patients resident in long-stay wards, the other of 29 patients normally resident in the community. Schizophrenic patients were individually matched for age, sex, and education with a healthy, normal subject. Both schizophrenic samples scored significantly lower on the Wechsler Adult Intelligence Scale (WAIS) than their respective control groups. NART-estimated IQ did not differ significantly between the community-resident schizophrenics and their controls, suggesting that the NART provides a valid means of estimating premorbid intelligence in such a population. NART-estimated IQ was significantly lower in the long-stay sample than in their controls. Although low NART scores in this latter sample could be a valid reflection of low premorbid IQ, the alternative explanation that NART performance was impaired by onset of the disease cannot be ruled out.

Short-forms of the UK WAIS-R: regression equations and their predictive validity in a general population sample

A sample of 200 healthy subjects, representative of the adult UK population in terms of age, sex and social class distribution, were administered a full-length WAIS-R (UK). Regression equations were built to predict full-length IQ from a series of short-forms. The short-forms ranged from a two-subtest version proposed by Silverstein (1982) to a seven-subtest version proposed by Warrington, James & Maciejewski (1986). Regression equations, their standard errors of estimate and confidence intervals are presented as well as IQ conversion tables. The short-forms are evaluated in terms of their validity in predicting full-length IQ and in terms of their clinical utility. The advantages of regression-based estimates of full-length IQ over those derived from conventional prorating are discussed.

Event related potentials, reaction time, and cognitive performance in idiopathic Parkinson's disease

Sixteen non-demented patients with idiopathic Parkinson's disease (PD) with varying degrees of cognitive impairment and sixteen age-, sex- and education-matched normal controls were examined with (1) an auditory oddball paradigm requiring counting or a motor response in separate determinations, (2) a reaction time task with movement time component and (3) a detailed clinical and neuropsychological test battery. Patients were impaired on a number of neuropsychological tests. They also showed an increased P2 and N2 latency, but no significant increase in P3 latency. Their response initiation times and reaction times during the oddball experiment were not different from controls, whereas movement time was significantly increased. Increased peak latencies, particularly for N2, were moderately associated with Parkinsonian motor impairment in patients and with the Benton Multiple Choice Visual Retention Test in patients and controls. Movement time was associated with P3 latency only in controls and in both groups with the Benton Multiple Choice Visual Retention Test. The observed pattern of results suggests that in non-demented PD patients ERP peak latencies, visuo-spatial task performance and Parkinsonian motor impairment share a significant degree of variance. While impairments in neuropsychological tests and delay in the earlier peaks P2 and N2 do not appear to be sensitive to medication with L-DOPA, normal P3 latencies might indicate good pharmacological symptom control in the absence of dementia.

The Short NART: cross-validation, relationship to IQ and some practical considerations

Beardsall & Brayne (1990) have presented a method whereby the full-length National Adult Reading Test (NART) scores of subjects who are of below average reading ability can be predicted from performance on the first half of the test (termed the Short NART). The accuracy with which the Short NART predicted full-length NART scores was examined in a large cross-validation sample (N = 674). A subgroup of this sample (N = 142) was administered the WAIS. The results indicated that the Short NART was only moderately successful in predicting full-length NART scores. However, comparison of the accuracy with which the full-length NART and Short NART predicted WAIS IQs, revealed that the superiority of the former was very minimal. It is concluded that, despite some reservations regarding the Short NART's practical utility, it can be used with reasonable confidence in clinical practice to estimate premorbid IQ.

Dementia in idiopathic Parkinson's disease: prevalence and relationship with symptoms and signs of parkinsonism

A whole population cohort of 157 patients with idiopathic Parkinsonism, most of whom had previously been clinically examined by Mutch (1986a), were assessed to determine prevalence figures for dementia and examine the relationship between dementia, cognitive impairment and Parkinsonian signs. Dementia according to DSM-III-R criteria was diagnosed in 23.3% of all patients (95% confidence interval: 17.1 to 32.4%). Dementia and cognitive impairment were associated with overall measures of Parkinsonian impairment and rigidity, but not tremor, even after controlling for age, sex and education.

Mortality and causes of death in idiopathic Parkinson's disease: results from the Aberdeen whole population study

Two hundred and forty-nine patients with Parkinson's disease previously examined by Mutch et al 1,2 were followed up three and a half years after the original study. Cognitive impairment, age, some postural signs and symptoms of Parkinson's disease and high scores on the Hoehn and Yahr scale predicted premature death. Patients were more likely to die from respiratory infections than controls. Respiratory diseases as cause of death recorded on the death certificate were not related to kyphosis, posture scores or Hoehn and Yahr scores before death. The hypothesis is advanced that death of respiratory causes might be associated with signs of general autonomic dysregulation.

Assessing the validity of NART-estimated premorbid IQs in the individual case

The National Adult Reading Test (NART: Nelson, 1982) has become the standard means of estimating premorbid intelligence. The danger in using the NART for this purpose is that it yields an invalid estimate if a client's performance on the test has suffered impairment. In the present study a sample of 659 healthy subjects was used to build a regression equation for the prediction of NART scores from demographic variables (i.e. years of education, social class, age and sex). The multiple correlation between these demographic variables and the NART was .70 (p less than .0001). Comparing a client's obtained and predicted NART score will permit the clinician to assess objectively whether NART performance is impaired, and thus whether or not the NART will provide a valid estimate of premorbid intelligence.

Regional cerebral blood flow imaging: a quantitative comparison of technetium-99m-HMPAO SPECT with C15O2 PET

The aim of this study was to compare technetium-99m-hexamethylpropyleneamineoxime (99mTc-HMPAO) single-photon emission computed tomography (SPECT) with regional cerebral blood flow (rCBF) imaging using positron emission tomography (PET). As investigation of dementia is likely to be one of the main uses of routine rCBF imaging, 18 demented patients were imaged with both techniques. The PET data were compared quantitatively with three versions of the SPECT data. These were, first, data normalized to the SPECT cerebellar uptake, second, data linearly corrected using the PET cerebellar value and, finally, data Lassen corrected for washout from the high flow areas. Both the linearly-corrected (r = 0.81) and the Lassen-corrected (r = 0.79) HMPAO SPECT data showed good correlation with the PET rCBF data. The relationship between the normalized HMPAO SPECT data and the PET data was nonlinear. It is not yet possible to obtain rCBF values in absolute units from HMPAO SPECT without knowledge of the true rCBF in one reference region for each patient.

Clinical features predicting dementia in idiopathic Parkinson's disease: a follow-up study

We followed up, after 3 1/2 years, a whole population cohort of 249 patients with Parkinson's disease (PD) 1st examined in 1983 to 1984. Of the survivors, 23.6% qualified for a DSM III-R diagnosis of dementia. In univariate tests, age, certain items of the Webster scale, the Hoehn and Yahr scale, a 10-question mental status questionnaire, and a history of smoking were associated with a diagnosis of dementia 3 1/2 years later. Logistic regression with DSM III-R diagnosis (demented versus nondemented) as the dependent variable, and age and symptom scales for PD as predictor variables, revealed that PD symptoms predicted dementia even after controlling for age. We conclude that dementia is probably more common in PD patients than would be expected in the general population and is associated with the severity of PD symptoms and signs independently of age.

Multimodal imaging in Alzheimer's disease. The relationship between MRI, SPECT, cognitive and pathological changes

Patients with a clinical diagnosis of Alzheimer's disease were studied using MRI, SPECT, and psychometric tests. Significant correlations between focal perfusion deficits and focal cognitive deficits were found. Significant correlations between regional relaxation time of white matter and psychometric tests of diffuse and focal categories were also found. Pathological examination confirmed Alzheimer's disease as the only diagnosis.

The Edinburgh cohort of HIV-positive drug users: current intellectual function is impaired, but not due to early AIDS dementia complex

Eighty people, all infected by HIV-contaminated drug injection equipment between 1983 and 1984, completed the National Adult Reading Test (NART) and selected revised Wechsler Adult Intelligence Scale (WAIS-R) subtests. Demographic variables (age, sex, years of education, and social class) were recorded as additional indices of premorbid functioning. Cross-sectional comparison of NART and WAIS-R scores showed that cognitive function was not more impaired with increasing severity of HIV illness, as defined by clinical staging. Nor were HIV-positive patients more impaired than a control group of seronegative drug users. Mean NART scores did not differ significantly from that predicted by a regression model, indicating that the NART can be reliably used to estimate premorbid intelligence for this population. However, current performance on WAIS-R subtests was below that expected from population models of cognitive function that combine measures of premorbid IQ and demographic factors, providing evidence of impaired intellectual function. Currently observed cognitive deficits are probably more due to drug use than to the insidious onset of AIDS dementia complex.

Improved detection of cognitive impairment with the NART: an investigation employing hierarchical discriminant function analysis

A series of discriminant function analyses was performed to examine the ability of the WAIS and NART to discriminate between healthy subjects and patients with dementia/cortical atrophy. Inclusion of NART estimated IQs in the analyses resulted in significantly greater discrimination than was achieved by WAIS IQs alone.

Parkinson's disease in Aberdeen: survival after 3.5 years

The increasing age of the general population and of patients suffering from Parkinson's disease suggests that a reappraisal of mortality rates and factors related to increased mortality should be carried out. A 3.5 year follow-up of a whole population sample of 267 patients and 233 controls matched by age, sex and general practitioner, yielded a relative mortality rate of 2.35 (99%-confidence interval: 1.60-3.43). Factors predicting death within the follow-up period were: cognitive impairment, old age, late age of onset, long history of smoking, lower blood pressure, and a variety of signs, symptoms and sequelae of Parkinson's disease associated with decreased mobility. However, age less than 70 years, age of onset before 66 years, absence of kyphosis or normal Webster posture score, mild impairment on the Hoehn & Yahr scale (1-2), or no impairment in a 10-question mental status questionnaire (9-10), were not associated with an increased risk of death.

A comparison of the WAIS and WAIS-R in matched UK samples

A matched samples design was employed to compare WAIS and WAIS-R IQ in UK subjects. The WAIS yielded significantly higher mean Full Scale, Verbal and Performance IQs. The mean differences were 7.5, 6.4 and 7.9 IQ points respectively. The WAIS and WAIS-R samples were broadly representative of the UK adult population in terms of age, sex and social class distribution, and therefore provide tentative estimates of population mean scores for both Wechsler scales. Mean WAIS IQ was 108.6, suggesting that the WAIS yields inflated IQ scores in the contemporary UK population. Encouragingly, mean WAIS-R Full Scale IQ was 101.1, suggesting that it neither markedly underestimates nor overestimates IQ in the UK.

Demonstration of savings on the AVLT and development of a parallel form

The purposes of the present study were (1) to investigate whether significant savings occur with repeat testing on Rey's Auditory-Verbal Learning Test and (2) to develop a parallel version of the AVLT. Subjects (N = 60) were divided into pairs (individually matched for sex, age, and education) to form two groups and were administered either the AVLT or a parallel version. Results indicated no significant differences on all AVLT measures of learning, recall, and recognition, suggesting that the parallel version can be used as an equivalent form of the AVLT. Subjects were retested after an interval of 27 (+/- 3) days, with half receiving the same version and half receiving a different version. In contrast to subjects receiving different lists, those who were retested with the same version demonstrated a significant improvement in performance on the majority of AVLT variables.

Magnetic resonance imaging in Alzheimer's disease, multi-infarct dementia, alcoholic dementia and Korsakoff's psychosis

Regional spin lattice relaxation times (T1) measured during nuclear magnetic resonance imaging of the brain were compared in patients with Alzheimer's disease, multi-infarct dementia, alcoholic dementia, Korsakoff's psychosis and control subjects. Regional differences were found between all patient groups compared with controls and within patient groups, with the exception of the comparison between Korsakoff's psychosis and alcoholic dementia. Correlations between regional T1 change and cognitive test scores were also found, with particular emphasis between visuospatial deficits and parietal T1. The possible role of T1 measures in the pathophysiology of these disorders is discussed.

Neuropsychological deficits and morphological MRI brain scan abnormalities in apparently healthy non-encephalopathic patients with cirrhosis. A controlled study

By means of psychometric testing, we have determined the frequency of latent hepatic encephalopathy in a group of 19 cirrhotics with no clinical evidence of encephalopathy. Magnetic resonance imaging (MRI) of the brain was performed in order to determine whether morphological cerebral abnormalities were associated with latent encephalopathy. Nineteen age and educationally matched patients with normal liver function acted as controls. Significant differences (P less than 0.05) between cirrhotics and controls were found in tests of short-term visual memory and speed of reaction to light (cirrhotics 316 +/- 132 ms vs. controls 225 +/- 36 ms), sound (cirrhotics 361 +/- 152 ms vs. controls 236 +/- 52 ms) and choice (cirrhotics 651 +/- 190 ms vs. controls 406 +/- 101 ms) stimuli (all values mean +/- S.D.). Reitan trail test performance, however, was similar in both groups. (Trail A: cirrhotics 43 +/- 19 s vs. controls 35 +/- 13 s; Trail B: cirrhotics 105 +/- 66 s vs. controls 93 +/- 36 s.) In patients with cirrhosis, MRI revealed statistically significant increases in the maximum fissure width of right frontal sulci, right and left parietal sulci, inter-hemispheric fissure width and in bicaudate index. These changes, indicating cerebral atrophy, were largely confined to alcoholics. There was poor correlation between measurements of cerebral morphology and neuropsychological performance, only 10% of associations achieving statistical significance.

Estimating premorbid IQ from demographic variables: regression equations derived from a UK sample

The purpose of the study reported here was to build regression equations for the estimation of premorbid IQ from demographic variables in a UK population. Subjects (n=151) free of neurological, psychiatric or sensory disability, were administered the Wechsler Adult Intelligence Scale (WAIS) and had their demographic details recorded (age, sex, occupation and education). WAIS Full Scale (FSIQ), Verbal (VIQ), and Performance IQ (PIQ) were regressed on the demographic variables. The regression equations generated by this procedure predicted 50, 50, and 30 percent of the variance in FSIQ, VIQ, and PIQ respectively. These equations should provide a convenient and useful supplement to psychometric estimates of premorbid IQ. Unlike psychometric estimates, demographic estimates are entirely independent of a patient's current cognitive status.

Does idiopathic parkinsonism in Aberdeen follow intrauterine influenza?

A study is presented which fails to replicate a recent report that peak years of birth of patients later developing Parkinson's disease are related to the influenza pandemics of the period 1890-1930. The years of birth of a whole population cohort of 243 patients suffering from Parkinson's disease examined in Aberdeen in 1983 and reexamined in 1986/7 were compared with deaths due to influenza in the City of Aberdeen in the years 1900-1930. Although a significant peak of Parkinson births (compared with the age profile of the Aberdeen population in 1983) occurred in 1902, there appeared to be no systematic relationship between Parkinson births and influenza deaths. In addition, no season of birth effect could be detected in a comparison with 232 matched controls. The presence of peaks of birth years, for whatever aetiological reason, is of significance to epidemiological studies in that prevalence estimates may be influenced by the year of study relative to these mini-cohorts.

Does endorsement of the disease concept of alcoholism predict humanitarian attitudes to alcoholics?

It has been widely assumed that the disease concept of alcoholism is a powerful vehicle for the promotion of humanitarian attitudes to alcoholics. However, Crawford and Heather have argued that individual differences in attitudes to alcoholics are liable to be a reflection of broader attitudes to deviancy rather than a function of endorsement/rejection of a disease conception. This argument was subjected to empirical scrutiny by means of a questionnaire distributed to 200 members of the public. The questionnaire (1) measured attitudes to four deviant groups--alcoholics, drug addicts, compulsive gamblers, and juvenile delinquents--and (2) recorded whether respondents endorsed or rejected a disease conception of these deviant conditions. Attitudes to the non-alcoholic deviant groups were better predictors of humanitarian attitudes to alcoholics than was endorsement of a disease conception of alcoholism.

Estimation of premorbid intelligence in organic conditions

The validity of premorbid IQ estimates provided by the National Adult Reading Test (NART) and Vocabulary sub-test of the Wechsler Adult Intelligence Scale were evaluated, by comparison with matched, healthy control subjects, in Korsakoff psychosis, alcoholic dementia, dementia Alzheimer type (DAT), multi-infarct dementia (MID), Huntington's disease, and closed head injury (CHI). There was no significant difference in NART performance between control subjects and the alcoholic dementia, DAT, MID, and CHI groups. Although there appeared to be a decline in NART performance in the Korsakoff and Huntington's groups, it did provide a significantly higher IQ estimate than the Vocabulary sub-test. All clinical groups, with the exception of the CHI group, performed at a significantly lower level than the control group on the Vocabulary sub-test.

Sinus histiocytosis with massive lymphadenopathy. Case report and review of a multisystemic disease with cutaneous infiltrates

A report of a patient with the rare syndrome of sinus histiocytosis with massive lymphadenopathy is presented here. This patient is unusual in several respects, including his longevity after diagnosis, the presence of a benign monoclonal gammopathy, and the characterization of his cutaneous infiltrates by immunofluorescent monoclonal antibody markers. A review of the literature on sinus histiocytosis with massive lymphadenopathy, with particular emphasis on cutaneous manifestations, is given.

The relationship between demographic variables and NART performance in normal subjects

The relationship between NART performance and demographic variables was examined in a group of subjects free of neurologic or psychiatric disorder (n = 201). NART estimated IQ was significantly correlated with education, social class and age. The correlation between age and NART IQ was no longer significant after partialling out either education or social class. There was no evidence of a curvilinear relationship between age and NART performance. There was no significant sex difference in NART performance. Nelson's (1982) report of a high split-half reliability was confirmed.

Estimation of premorbid intellectual status in depression

The validity of the NART and Vocabulary subtest of the WAIS as measures of premorbid IQ in depression was assessed by comparing a group of depressed patients (n = 39) with matched controls. The Vocabulary performance of the depressed group was significantly poorer than controls but there was no significant difference in NART performance.

Differential diagnosis in dementia using the cerebral blood flow agent 99mTc HM-PAO: a SPECT study

One of the potential clinical uses of the new cerebral blood flow agent 99mTc-hexamethylpropyleneamineoxime (HM-PAO) is the investigation of dementia, in particular to differentiate between dementia of the Alzheimer type (DAT) and multiinfarct dementia (MID). In this study 27 patients, 17 with DAT and 10 with MID, and three normal volunteers were imaged both with single photon emission CT and magnetic resonance. The HM-PAO perfusion deficits were much more common in the DAT group than in the MID group, especially in the temporoparietooccipital (TPO) regions. The two groups of patients were found to be significantly different (p less than 0.02), as regards the frequency of occurrence of bilateral TPO perfusion deficits. Four of the 17 DAT patients did not have bilateral TPO deficits but these included the three least impaired patients as assessed by psychometric testing.

Nuclear magnetic resonance imaging and single photon emission tomography with radio-iodine labelled compounds in the diagnosis of dementia

White matter lesions and T1 changes were identified using NMR and then compared between groups of patients suffering from dementia of the Alzheimer type (DAT), Multiple infarct dementia (MID) and normal controls. All DAT and MID patients were also imaged with a gamma camera using 123Iodo-n-isopropyl-amphetamine, a radiopharmaceutical whose uptake in the brain follows the regional blood flow. While NMR was not able to differentiate between DAT and MID, 19 out of 21 DAT patients compared to four out of 18 MID patients showed bilateral parietal lesions on IMP scans.