D-KEFS trail making test as an embedded performance validity measure.

OBJECTIVE: The Delis-Kaplan Executive Function System (D-KEFS) Trail Making Test (TMT) is a commonly used measure of processing speed and executive functioning that may also be useful as an embedded performance validity test (PVT). We evaluated the utility of several multi-condition indices on the D-KEFS TMT in three independent samples to determine an optimal multi-condition index and cutoff on the D-KEFS TMT. METHOD: Classification accuracy statistics for multiple multi-condition indices on the D-KEFS TMT were evaluated in three independent samples, including a sample with history of mild traumatic brain injury (TBI; n = 267) classified into psychometrically defined performance-valid and performance-invalid subgroups, the D-KEFS national normative sample (n = 1713), and a sample of middle- and older-aged adults diagnosed with mild cognitive impairment (MCI; n = 70). RESULTS: The D-KEFS TMT Conditions 1-5 summation index maximized sensitivity at .31 while maintaining adequate specificity at ≥.9. This index also had acceptable classification accuracy in both the D-KEFS national normative and MCI cross-validation samples, with the exception of the oldest subgroup of the national norming sample (i.e., individuals' ages 80-89), in which the observed failure rates for all multi-condition indices tested were greater than 10%. CONCLUSION: Our study provides support for the use the D-KEFS TMT Conditions 1-5 summation index as an embedded PVT among individuals younger than 80 years-old and from a range of conditions spanning from cognitively normal to mildly impaired; however, further validation is necessary.

Brainstem white matter integrity is related to loss of consciousness and postconcussive symptomatology in veterans with chronic mild to moderate traumatic brain injury.

We investigated associations between DTI indices of three brainstem white matter tracts, traumatic brain injury (TBI) injury characteristics, and postconcussive symptomatology (PCS) in a well-characterized sample of veterans with history of mild to moderate TBI (mTBI). 58 military veterans (mTBI: n = 38, mean age = 33.2, mean time since injury = 90.9 months; military controls [MC]; n = 20; mean age = 29.4) were administered 3T DTI scans as well as a comprehensive neuropsychiatric evaluation including evaluation of TBI injury characteristics and PCS symptoms (e.g., negative mood, dizziness, balance and coordination difficulties). Tractography was employed by seeding ROIs along 3 brainstem white matter tracts (i.e., medial lemniscus-central tegmentum tract [ML-CTT]; corticospinal tracts [CST], and pontine tegmentum [PT]), and mean DTI values were derived from fractional anisotropic (FA) maps. Results showed that there were no significant difference in FA between the MC and TBI groups across the 3 regions of interest; however, among the TBI group, CST FA was significantly negatively associated with LOC duration. Additionally, lower FA of certain tracts-most especially the PT-was significantly associated with increased PCS symptoms (i.e., more severe vestibular symptoms, poorer physical functioning, and greater levels of fatigue), even after adjusting for PTSD symptoms. Our findings show that, in our sample of veterans with mTBI, tractography-based DTI indices of brainstem white matter tracts of interest are related to the presence and severity of PCS symptoms. Findings are promising as they show linkages between brainstem white matter integrity and injury severity (LOC), and they raise the possibility that the pontine tegmentum in particular may be a useful marker of PCS symptoms. Collectively, these data point to important neurobiological substrates of the chronic and complex constellation of symptoms following the 'signature injury' of our combat-exposed veterans.

Distinct profiles of brain and cognitive changes in the very old with Alzheimer disease.

OBJECTIVE: To determine whether age-standardized brain morphometric and cognitive profiles differ in young-old (aged 60-75 years) and very-old (aged 80-91 years) patients with Alzheimer disease (AD). METHODS: Using a case-control retrospective design, we compared hippocampal volume and cortical gray matter thickness in areas known to be affected by AD in 105 patients with AD and 125 healthy control (HC) participants divided into young-old and very-old subgroups. Brain morphometric and cognitive scores of the AD groups were standardized to their respective age-appropriate HC subgroup and then compared. RESULTS: Several cognitive domains (executive function, immediate memory, and attention/processing speed) were less abnormal in the very old with AD than in the young old with AD. Similarly, the very old with AD showed less severe cortical thinning than the young old with AD in the left posterior cingulate cortex, right lateral temporal cortex, and bilateral parietal cortex and in overall cortical thickness. This effect is partially explained by an age-related decrease in cortical thickness in these brain regions in the HC participants. CONCLUSIONS: The typical pattern of AD-related cognitive and morphometric changes seen in the young old appear to be less salient in the very old. Thus, mild cases of AD in the very old may go undetected if one expects to see the prototypical pattern and severity of cognitive or brain changes that occur in the young old with AD. These results underscore the importance of interpreting neuropsychological test performance and morphometric brain measures in reference to the individual's age.

Global clinical dementia rating of 0.5 in MCI masks variability related to level of function.

OBJECTIVE: To evaluate whether ratings on Clinical Dementia Rating (CDR) items related to instrumental activities of daily living (IADL) are associated with cognitive or brain morphometric characteristics of participants with mild cognitive impairment (MCI) and global CDR scores of 0.5. METHODS: Baseline cognitive and morphometric data were analyzed for 283 individuals with MCI who were divided into 2 groups (impaired and intact) based on their scores on the 3 CDR categories assessing IADL. Rates of progression to Alzheimer disease (AD) over 2 years were also compared in the 2 groups. RESULTS: The impaired IADL MCI group showed a more widespread pattern of gray matter loss involving frontal and parietal regions, worse episodic memory and executive functions, and a higher percentage of individuals progressing to AD than the relatively intact IADL MCI group. CONCLUSIONS: The results demonstrate the importance of considering functional information captured by the CDR when evaluating individuals with MCI, even though it is not given equal weight in the assignment of the global CDR score. Worse impairment on IADL items was associated with greater involvement of brain regions beyond the mesial temporal lobe. The conventional practice of relying on the global CDR score as currently computed underutilizes valuable IADL information available in the scale, and may delay identification of an important subset of individuals with MCI who are at higher risk of clinical decline.

Elevated pulse pressure is associated with age-related decline in language ability.

Recent research suggests that pulse pressure (PP), a putative marker of vascular integrity, may be associated with brain microvascular damage and age-related cognitive decline. Thus, the present study examined the relationship between PP and cognition in a sample of healthy nondemented older adults. One hundred nine participants were administered neurological and neuropsychological evaluations and determined to be nondemented. Regression analyses were used to examine the relationships among pulse pressure (PP) [systolic blood pressure (SBP)--diastolic blood pressure (DBP)], age, and cognition. PP and related measures were inversely correlated with global cognitive functioning and scores on a composite measure of language function, even after adjusting for age, education, and relevant vascular risk factors. Results indicate that increases in the pulsatile component of blood pressure may convey added risk of global cognitive decline and specific impairment in language abilities.

Decreased white matter integrity in late-myelinating fiber pathways in Alzheimer's disease supports retrogenesis.

The retrogenesis model of Alzheimer's disease (AD) posits that white matter (WM) degeneration follows a pattern that is the reverse of myelogenesis. Using diffusion tensor imaging (DTI) to test this model, we predicted greater loss of microstructural integrity in late-myelinating WM fiber pathways in AD patients than in healthy older adults, whereas differences in early-myelinating WM fiber pathways were not expected. We compared 16 AD patients and 14 demographically-matched healthy older adults with a whole-brain approach via tract-based spatial statistics (TBSS), and a region of interest (ROI) approach targeting early-myelinating (posterior limb of internal capsule, cerebral peduncles) and late-myelinating (inferior longitudinal fasciculus [ILF], superior longitudinal fasciculus [SLF]) fiber pathways. Permutation-based voxelwise analysis supported the retrogenesis model. There was significantly lower fractional anisotropy (FA) in AD patients compared to healthy older adults in late-myelinating but not early-myelinating pathways. These group differences appeared to be driven by loss of myelin integrity based on our finding of greater radial diffusion in AD than in healthy elderly. ROI analyses were generally in agreement with whole-brain findings, with significantly lower FA and increased radial diffusion in the ILF in the AD group. Consistent with the retrogenesis model, AD patients showed demonstrable changes in late-myelinating WM fiber pathways. Given greater change in the ILF than the SLF, wallerian degeneration secondary to cortical atrophy may also be a contributing mechanism. Knowledge of the pattern of WM microstructural changes in AD and its underlying mechanisms may contribute to earlier detection and intervention in at-risk groups.

Neurocognitive functioning in dually diagnosed middle aged and elderly patients with alcoholism and schizophrenia.

BACKGROUND: Alcohol abuse and dependence have important clinical implications for managing patients with schizophrenia. Alcoholism in schizophrenia patients can interfere with the course and prognosis of the schizophrenic illness. OBJECTIVE: The purpose of the present study was to compare the cognitive status, symptom profile and quality of life of middle aged and older patients (>44 years old) with schizophrenia and alcohol abuse/dependence vs those without alcohol abuse/dependence. We initially hypothesized that more males in this age group with schizophrenia would exhibit alcoholism. We also examined the characteristics of the 45-54 year age group with those of the > or = 55 year old group and hypothesized that comorbidity with alcohol would be associated with worse cognition and quality of life in later life. METHODS: Data were obtained from a database from the Center for Services and Interventions research at the University of California, San Diego. Patients had diagnoses of schizophrenia or schizoaffective disorder. Data collected included demographic characteristics, cognitive status (tested with the Mattis Dementia Rating Scale learning, the Figural and Story Memory Test of the Wechsler Memory Scale-Revised and the California Verbal Learning Test [CVLT]). In addition, patients had undergone psychopathologic assessment and were screened for quality of life using the Quality of Well Being scale. RESULTS: We demonstrated that the older aged patients with alcoholism had worse scores assessing cognition relative to the same aged group without alcoholism. In addition, they had worse cognitive scores relative to the younger group (45-54 year old) with alcoholism. There was no significant difference with regards to quality of life. In addition, more males than females exhibited alcoholism. CONCLUSION: The results are consistent with the premise that the higher cognitive function in the younger schizophrenia patients with alcoholism appear to mask the effects of alcohol use on cognition at that age. However, for the older group of schizophrenia patients, the effects of alcohol use on neuropsychological functioning appear to be deleterious.

Comparison of the serial position effect in very mild Alzheimer's disease, mild Alzheimer's disease, and amnesia associated with electroconvulsive therapy.

Individuals given a series of words to memorize normally show better immediate recall for items from the beginning and end of the list than for mid-list items. This phenomenon, known as the serial position effect, is thought to reflect the concurrent contributions of secondary and primary memory, respectively, to recall performance. The present study compared the serial position effects produced on Trial 1 of the California Verbal Learning Test (CVLT) in mildly demented (N = 25; M MMSE = 20.0) and very mildly demented (N = 25; M MMSE = 25.5) patients with Alzheimer's disease (AD), and age- and education-matched normal control (NC) participants (N = 50). In addition, the serial position effects of the very mildly demented AD patients were compared to those of patients with a transient, circumscribed amnesia arising from a prescribed series of electroconvulsive therapy (ECT) treatments for the relief of depressive illness (N = 11). While the NC group exhibited the typical serial position effect, AD patients recalled significantly fewer words than NC participants overall, and exhibited a significantly reduced primacy effect (i.e., recall of the first 2 list items) with a normal recency effect (i.e., recall of the last 2 list items). Patients with circumscribed amnesia due to ECT were as impaired as the very mildly demented AD patients on most standard CVLT measures of learning and memory, but exhibited primacy and recency effects, which were within normal limits. These results suggest that a reduction in the primacy effect, but not the recency effect, is an early and ubiquitous feature of the memory impairment of AD. It is not, however, a necessary feature of all causes of memory impairment.

Neuropsychological function and apolipoprotein E genotype in the preclinical detection of Alzheimer's disease.

Nondemented older adults genotyped for the Apolipoprotein E (ApoE) epsilon4 allele (n = 43) were neuropsychologically compared to participants without a copy of the epsilon4 allele (n = 90). At baseline, the groups did not differ on age, education, gender, or global cognitive status. ApoE-epsilon4 participants demonstrated significantly poorer mean performances on delayed recall, but no significant group differences emerged on attention, language, constructional skills, psychomotor speed, or executive function. Significantly more ApoE-epsilon4 participants developed probable or questionable Alzheimer's disease (AD) compared with non-epsilon4 participants, suggesting that the group differences resulted from a preponderance of preclinical AD cases within the epsilon4 group and not from a direct influence of ApoE genotype on cognition. Cox proportional hazards analysis, adjusting for age, years of education, and global cognitive status, revealed that ApoE-epsilon4 allele status and measures of recall performance were significant and independent predictors of conversion to AD. Results support the importance of specific episodic memory changes and possession of the ApoE-epsilon4 allele in the preclinical detection of AD.

Regional cerebral volume loss associated with verbal learning and memory in dementia of the Alzheimer type.

Twenty-seven research participants with dementia of the Alzheimer type were studied with the California Verbal Learning Test (D. C. Delis, J. H. Kramer, E. Kaplan, & B. A. Ober, 1987) and standardized volume measures of the mesial temporal cortical gray matter, neocortical gray matter, thalamus, and caudate nuclei, from magnetic resonance imaging. A pattern of atrophic brain changes in the mesial temporal lobes (MTL) and the thalamus, with relatively less severe atrophy in the neocortical gray matter, was associated with poorer learning of the word list. Similar patterns of brain atrophy were observed for measures of delayed recall and recognition hits. However, for delayed recall, neither contribution was statistically significant, and for recognition hits, MTL was only at the trend level for significance. These results provide evidence that the verbal memory deficit of Alzheimer's disease (AD) is associated not only with the mesial temporal limbic cortex, thought to be the site of earliest and most severe pathology in AD, but also with damage in the thalamus.

Verbal learning and memory in alcohol abusers and polysubstance abusers with concurrent alcohol abuse.

To define the combined effects of drug and alcohol abuse on verbal learning and memory, 70 alcoholic and 80 polysubstance abuse (PSA) individuals with concurrent alcohol abuse were compared on a list learning task, the California Verbal Learning Test (CVLT). Despite demonstrating similar learning strategies, response styles, and error patterns, the PSA group nontheless exhibited significantly greater recall deficits than the alcoholic group on the CVLT. These deficits were particularly evident in those who were heaviest abusers of cocaine. PSA participants did not, however, evidence greater recognition memory deficits. This pattern of greater deficits on recall than on recognition memory, as well as poor consolidation, is consistent with the initiation-retrieval difficulties of patient groups with subcortical dysfunction. It is concluded that the combined use of alcohol and drugs, cocaine in particular, may compound memory difficulties beyond what is typically observed in alcoholic individuals.

Very early changes in olfactory functioning due to Alzheimer's disease and the role of apolipoprotein E in olfaction.

Alzheimer's disease (AD) is a progressive neurodegenerative illness marked by memory loss and at least one other cognitive disturbance. Early diagnosis of the disease has proved difficult and has therefore been the focus of much research. Apolipoprotein E (ApoE), a protein manufactured and distributed throughout the body, has shown specificity of binding to the beta A4 peptide, the primary component in the senile plaques of AD. Furthermore, the ApoE, epsilon 4 (epsilon 4) allele, is overrepresented in AD. These two lines of evidence suggest that ApoE, specifically the epsilon 4 allele, plays an important role in the development of AD. Further support for this hypothesis appears in neuropsychological data showing cognitive decrements in ostensibly nondemented individuals with the epsilon 4 allele, compared to those without the allele. It is also well known that olfaction is compromised in AD. Thus, the purpose of this study was twofold: (1) to examine very early changes in olfactory functioning due to AD and (2) to examine the role of ApoE in olfactory functioning in people at risk for AD by virtue of early cognitive decline. Results demonstrated changes in olfactory threshold the year immediately preceding change in diagnosis from normal control to AD. Also, in individuals with mild cognitive impairment, those with the ApoE epsilon 4 allele show poorer thresholds than those without the epsilon 4 allele.

Apolipoprotein E status is associated with odor identification deficits in nondemented older persons.

Alzheimer's disease (AD) patients with moderate dementia show losses in olfactory threshold, odor identification and odor memory. Sensitivity and specificity of olfactory testing is significant, with the greatest power of accurate diagnosis in the more cognitively loaded olfactory tasks. In patients with very mild AD or in patients at risk for the disease because of their mild cognitive impairment, losses are apparent for odor identification, odor recognition memory and odor threshold, with the best sensitivity in the identification task. Persons who are either heterozygous or homozygous for the epsilon 4 allele of apolipoprotein E (ApoE) have an increased risk of Alzheimer's disease, although they show no dementia in the preclinical period. Evidence of olfactory dysfunction in this population might be reflective of an incipient dementing process. We have recently examined olfactory function in a group of normal elderly persons who have undergone genetic testing for the Apoe4 allele. These individuals consisted of all normal control subjects at the University of California, San Diego (UCSD) Alzheimer's Disease Research Center (ADRC) who had undergone both the genetic testing and testing for olfactory function. All had been diagnosed as normal control participants by two different neurologists who applied the National Institute of Neurological Disorders and Stroke and the Alzheimer's Disease and Related Disorders Association (NINDS-ADRDA) criteria for dementia. Persons with a history of alcoholism, drug abuse, learning disability or neurologic or psychiatric illness (including depression) were excluded. In this population, persons with the Apoe4 allele showed significantly poorer odor identification than those without an epsilon 4 allele. Early appearance of olfactory deficits in the progression to AD in persons with the epsilon 4 allele suggests diagnostic utility in olfactory testing.

A population-based analysis of qualitative features of the neuropsychological test performance of individuals with dementia of the Alzheimer type: implications for individuals with questionable dementia.

Qualitative features of the neuropsychological test performance of individuals with dementia of the Alzheimer type (DAT) were examined in a population-based study. Qualitative error scores were derived from measures of verbal and figural memory, verbal fluency and confrontation naming for 38 patients with clinically diagnosed DAT, 236 normal elderly (NE) individuals, and 72 others who were questionably demented and at risk (AR) for DAT. Persons with DAT made a greater proportion of intrusion and perseverative errors, and more lexical and semantic naming errors, than the NE participants. These measures provided fair specificity but poor sensitivity for the diagnosis of DAT, and a logistic model based on these measures correctly classified 98% of the NE participants, but only 29% of the DAT participants. The AR participants demonstrated a pattern of errors that was highly similar to that of the DAT patients, and when their scores were subjected to the logistic model, 90% were classified as NE and 10% as DAT. These results indicate that specific error types that have been associated with DAT in self-referred or clinic-based samples also occur in the general population to a greater degree in individuals with DAT or questionable dementia than in NE individuals. Furthermore, these qualitative features may have some diagnostic usefulness in that their presence provides reasonable specificity for DAT or questionable dementia.

Hippocampal sclerosis contributes to dementia in the elderly.

OBJECTIVE: To assess the relevance of hippocampal sclerosis (HS) to dementia in the elderly. BACKGROUND: HS is a prominent pathologic finding in some demented elderly, but the anatomic substrate and cognitive profiles of this dementia have not been well established. DESIGN/METHODS: An autopsy series, including dot-immunobinding assay to estimate neocortical synaptic density, of eight patients (three men, five women) with HS on whom extensive antemortem neuropsychological testing was available. RESULTS: Mean age at onset was 72.0 (+/-9.8) (range, 59 to 89) with a mean duration of symptoms of 6.5 (+/-2.9) years. Patients were only mildly impaired with a mean MMSE of 20.9 (+/-4.9) and a mean DRS of 103.1 (+/-12.5) at presentation. Cardiovascular disease was present in 88%, with a mean Hachinski score of 3.4 (+/-2.2). No patient had a history of seizures. Sixty-three percent had depression or depressive symptoms. Neuropsychologically, most patients presented with prominent memory and language deficits and became progressively demented. Neuropathologically, isolated HS was a rare finding; many patients had either very mild or neocortical "plaque only or plaque predominant" Alzheimer's disease (AD) in addition to HS changes. Midfrontal neocortical synaptophysin counts were significantly reduced in all HS patients compared with controls (p = 0.0006). CONCLUSIONS: In the elderly, HS can be a neuropathologic substrate of dementia. Clinically, it can be associated with a course that is difficult to distinguish from AD although cardiac disease and depression are frequent concomitants. Deterioration of cognitive function in these subjects may relate to other pathologic features such as neocortical synapse loss.

Deterioration of generic knowledge in patients with Alzheimer's disease: evidence from the Number Information Test.

Semantic memory for generic knowledge was assessed in patients with probable Alzheimer's disease (AD; n = 142) and elderly normal control (NC; n = 78) subjects using the Number Information Test (NIT), a test that consists of 24 general knowledge questions that require a single number for an answer (e.g., "How many days are in a year?"). The results showed that patients with AD were impaired, even in the mildest stage of dementia, and that this impairment grew as the severity of their dementia increased over time. In addition, patients with AD were highly consistent in the individual items they missed in subsequent test sessions conducted 1 or 2 years later. These results indicate that semantic memory for generic knowledge is impaired relatively early in AD, deteriorates throughout the course of the disease, and may be due to a loss of knowledge rather than to a retrieval deficit.

Longitudinal examination of American National Adult Reading Test (AMNART) performance in dementia of the Alzheimer type (DAT): validation and correction based on degree of cognitive decline.

The American National Adult Reading Test (AMNART) was constructed to provide a valid and stable estimate of premorbid verbal IQ (VIQ) in dementing individuals. However, recent studies have brought into question its validity in patients with dementia of the Alzheimer type (DAT). The present study was designed to longitudinally assess the validity of the AMNART in 40 DAT patients and 40 demographically matched normal control (NC) subjects. The results showed that VIQ estimates for patients with DAT were significantly lower than those of NC subjects and declined significantly over time with increasing dementia severity as measured by the Mini-Mental State Examination (MMSE) and the Dementia Rating Scale (DRS). An MMSE-based correction factor was derived for the DAT group which allows for the effective estimation of premorbid VIQ in these patients.

Episodic memory changes are associated with the APOE-epsilon 4 allele in nondemented older adults.

OBJECTIVE: To compare the memory performances of nondemented older adults with and without the epsilon 4 allele of the apolipoprotein E (APOE-epsilon 4). BACKGROUND: Few studies have examined the cognitive status of subjects at high risk for the development of dementia of the Alzheimer type (DAT). A newly reported risk factor for DAT allows for an examination of the cognitive performances of nondemented subjects who are at risk by virtue of being either heterozygous or homozygous for the APOE-epsilon 4 allele. METHODS: The California Verbal Learning Test (CVLT) was administered to 52 nondemented older adults. Subjects were divided into two groups on the basis of the presence (n = 17) or absence (n = 35) of one or two APOE-epsilon 4 alleles. RESULTS: APOE- epsilon 4 and non-epsilon 4 groups did not significantly differ in demographic, mental status, and functional characteristics. APOE-epsilon 4 subjects demonstrated significantly poorer mean performances than non-epsilon 4 subjects on nine CVLT variables. Seven group differences remained significant, and three approached significance (0.05 < p < 0.10), after the effects of age and gender were taken into account. Six of the 14 APOE-epsilon 4 subjects who completed annual follow-up evaluations developed either DAT or questionable DAT, whereas none of the 26 non-epsilon 4 subjects who received follow-up demonstrated any cognitive decline. CONCLUSIONS: Results suggest that episodic memory changes in older adults are associated with APOE-epsilon 4 allele; sensitive cognitive markers such as those of the CVLT may precede the subsequent development of DAT.

Clinical validity of the Mattis Dementia Rating Scale in detecting Dementia of the Alzheimer type. A double cross-validation and application to a community-dwelling sample.

OBJECTIVE: To assess the clinical validity of the Dementia Rating Scale (DRS) in detecting patients with dementia of the Alzheimer type (DAT). BACKGROUND: The DRS is widely used to evaluate cognitive functioning in older adults. Adequate normative data are unavailable; studies addressing the clinical validity of the DRS are limited by small sample sizes. DESIGN AND METHODS: Administered the DRS to 254 outpatients with DAT and 105 healthy elderly subjects. Performed (1) multiple regressions of demographic factors on the DRS and its subscales; (2) derivation of optimal DRS cutoff scores using receiver operating characteristic curves; (3) double cross-validation with stepwise logistic regressions; and (4) application of results to a community-dwelling sample. RESULTS: Age- and education-adjusted DRS scores were computed. The optimal DRS cutoff score for DAT of 129 or less revealed a sensitivity of 98% and a specificity of 97%. The logistic regressions resulted in a combination of the Memory and Initiation/Perseveration subscales that correctly classified 98% of all subjects, 92% of a subsample of 76 patients with mild DAT, and 100% of the 51 patients with autopsy-confirmed DAT. The resultant equation was then applied to a community-dwelling sample (238 healthy elderly subjects and 44 patients with DAT): 91% of patients and 93% of normal subjects were correctly classified. Of an additional 77 individuals with questionable DAT, 43 were classified as demented and 34 were classified as nondemented. CONCLUSIONS: The DRS is a clinically valid psychometric test for the detection of DAT. The Memory and Initiation/Perseveration subscales are its best discriminative indexes for an abbreviated version.

Discrimination of cortical from subcortical dementias on the basis of memory and problem-solving tests.

This study compared the discriminative utility of problem-solving and memory tasks in patients with Alzheimer's and Huntington's disease and in age-, education-, and gender-matched normal control subjects. Problem-solving was assessed with a modified version of the Wisconsin Card Sorting Test. Memory was measured with a 10-item, 6-trial version of the Buschke Selective Reminding Test. Receiver Operating Characteristic curves were plotted to determine which measure provided the highest sensitivity (i.e., hit rate) and specificity (i.e., correct rejection rate). Both tests provided excellent detection of dementia (88 to 98% classification accuracy), but were less robust in differentiating between dementia groups. Findings underscore the suitability of both measures to detect mild dementia, but emphasize the importance of specific memory measures to differentiate between cortical and subcortical dementia.