Confrontation naming impairment in dementia

Boston Naming Test in Alzheimer's disease

The 60-item Boston Naming Test (BNT) was administered to 55 subjects: 15 mildly-to-moderately demented patients meeting NINCDS-ADRDA criteria for "probable" Alzheimer's disease (AD), 15 age-equivalent normal control (NC) subjects, and--for purposes of validation--25 additional subjects with other forms of dementia (OD). A cutting score of 51 correctly classified 80% of AD patients and 86% of NC subjects. To facilitate rapid screening of confrontation-naming performance in these populations, three 30-item shortened versions of the BNT were constructed. Even and Odd Versions were equivalent for AD, NC, and OD subjects; high correlations between these two and the 60-item BNT permit easy extrapolation to a total BNT score. A new Empirical Version, derived from performance of our AD and NC reference groups, maintained most of the intergroup discrimination of the full BNT.

The problem of naming in SDAT: a relative deficit

Research relating to language disorder in senile dementia of the Alzheimer type (SDAT) has focused primarily on naming impairment, formally termed anomia or nominal aphasia/dysphasia. Data resulting from this research have been insufficiently informed by a comparative linguistic framework in which performance on naming tasks is contrasted with performance on other forms of language tasks. The present study involves the comparison of 21 adults with SDAT and 18 demographically controlled normal elderly adults on the Test for Syntactic Complexity and fifteen subtests of the Western Aphasia Battery. Performance on naming is compared with performance on oral language variables of repetition, yes/no response, auditory word recognition, sequential commands, syntactic processing, as well as with performance on reading tasks and non-verbal tasks. Findings relating to oral language tasks show that structured syntactic processing requiring explicit interpretation and sequential commands are significantly more difficult for the SDAT sample than are three of four naming tasks. Further, significant SDAT performance variability is found across naming tasks. The generative categorical naming task is found to be significantly more difficult for the SDAT patient than are the other three naming tasks. It is concluded that the generative categorical naming task should be regarded as a meta-naming task. In sum, it is found that although language dysfunction in SDAT has anomic components, the essential character of the language disorder is not best conceptualized as a problem of naming.

Equivalent spatial-rotation deficits in normal aging and Alzheimer's disease

Two tests of spatial-rotation ability were administered to 17 young normals, 23 aged normals, and 51 patients with diagnoses of Alzheimer's disease (AD). The AD patients consisted of 28 early dementia patients and 23 advanced dementia patients. On a computerized version of the Boston Naming Test, 40 objects were presented for naming, 20 of which were rotated 180 degrees. The subjects' capacity for mental rotation was assessed on the basis of their accuracy of naming of rotated vs. unrotated objects. On Money's Standardized Road Map Test, in which the subject is asked whether turns on a map are to the left or to the right, spatial-rotation ability was assessed on the basis of the subject's left-right orientation on turns with movement away from the subject (requiring no rotation) vs. turns with movement toward the subject (requiring rotation). Performance on both tasks was progressively worse in the young normal, aged normal, early dementia, and advanced dementia groups. Both tasks demonstrated a clear spatial-rotation deficit in the elderly. Although the spatial-rotation effect was superimposed upon deficits in naming and left-right orientation in the demented subjects, the magnitude of the rotation effect did not significantly differ in the aged normal vs. the early dementia group on either task, suggesting that early AD produces no further impairment of spatial-rotation abilities than is produced by normal aging.

Lexical and semantic priming deficits in patients with Alzheimer's disease

Two experiments utilizing priming procedures examined the status of semantic memory in demented and amnesic patients. In the first investigation, lexical priming was assessed in patients with dementia of the Alzheimer type (DAT), Huntington's Disease (HD), alcoholic Korsakoff's syndrome (KS), and in intact control subjects. Subjects were first exposed to a list of words in a rating task and then required to complete three-letter stems with the "first word that comes to mind". Half of the stems could be completed with the previously presented words and the other half were used to assess baseline guessing rates. Recall and recognition of incidentally exposed words was also assessed. Although all three patient groups were impaired on tests of recall and recognition, only the DAT patients exhibited a priming deficit on the stem-completion task. In the second experiment, DAT, HD, and intact control subjects were administered a semantic priming test which required the subject to "free associate" to the first words of previously presented semantically associated word pairs. The results for this association task showed that DAT patients were significantly less likely to produce the second word of the semantically related pair than were the other subject groups. The results of these two experiments suggest that the memory capacities of DAT patients are characterized by a breakdown in the structure of semantic memory and that this impairment is evident on some "automatic" as well as "effortful" processing tasks.

Integrity of semantic fields in Alzheimer's disease

It has been suggested that Alzheimer patients retain general semantic knowledge about concrete objects (e.g., category membership) but lose information about objects' distinctive features and functions. To test this hypothesis, normal young and old subjects and Alzheimer patients were given a concrete concept. They were then shown a series of words and for each had to say whether it was related to the concept. Of the words that were related to a given concept, one was a physical feature, another a function, another the object's superordinate category, and another a generally associated concept. In comparison to the normals, Alzheimer patients were not disproportionately worse at making decisions about features and actions than they were about categories and general associates. Also, while Alzheimer patients were less accurate in generating features, actions and associates to a given concept than were normals, they were not differentially more impaired on any one type.

On the neurolinguistic nature of language abnormalities in Huntington's disease

Spontaneous language of 18 patients suffering from Huntington's disease and 15 dysarthric controls suffering from Friedreich's ataxia were investigated. In addition, language functions in various modalities were assessed with the Aachen Aphasia Test (AAT). The Huntington patients exhibited deficits in the syntactical complexity of spontaneous speech and in the Token Test, confrontation naming, and language comprehension subtests of the AAT, which are interpreted as resulting from their dementia. Errors affecting word access mechanisms and production of syntactical structures as such were not encountered.

Language and dementia: a review

In the literature on dementia the presence or absence of language deficits has come to occupy a pivotal position with respect to certain nosological and nosographical issues. These are reviewed critically, together with the results of experimental investigations which have sought to elucidate the nature of the language deficit(s) in patients with dementia, especially that of the Alzheimer type. Attention is drawn to important gaps in current knowledge and suggestions are made regarding the direction of future research.

Intellectual impairment in Parkinson's disease: clinical, pathologic, and biochemical correlates

The prevalence of overt dementia in 27 studies representing 4,336 Parkinson's disease (PD) patients was 39.9%. The studies reporting the highest incidence of intellectual impairment (69.9%) used psychologic assessment techniques, whereas studies identifying the lowest prevalence of dementia (30.2%) depended on nonstandardized clinical examinations. Neuropsychologic investigations reveal that PD patients manifest impairment in memory, visuospatial skills, and set aptitude. Language function is largely spared. Intellectual deterioration in PD correlates with age, akinesia, duration, and treatment status. Neuropathologic and neurochemical observations demonstrate that PD is a heterogeneous disorder: the classic subcortical pathology with dopamine deficiency may be complicated by atrophy of nucleus basalis and superimposed cortical cholinergic deficits, and a few patients have the histopathologic hallmarks of Alzheimer's disease. Mild intellectual loss occurs with the classic pathology, and the more severe dementia syndromes have cholinergic alterations or Alzheimer's disease. Thus, PD includes several syndromes of intellectual impairment with variable pathologic and neurochemical correlates.

Cognitive and brain imaging measures of Alzheimer's disease

Diagnosis of Alzheimer's disease (AD) during life relies upon clinical and neurobehavioral symptoms but is presumptive without microscopic verification of neuropathology. Studies in this review observed considerable heterogeneity in AD symptoms and did not agree on how to detect the earliest symptoms. Problems exist in diagnosis. Differences in symptoms and diagnosis result from how AD is defined neurobehaviorally and on the model used for description. The studies reviewed have been considered under three basic models: A severity (staging) model; a heterogeneity (subtyping) model; and an information processing model. Differences in model intent have resulted in differences in disease description. Brain imaging measures have not invalidated models but add the neural substrate needed to examine correlation of measures within each model.

The use of phonemic cueing with Alzheimer's disease patients

Variables influencing responsiveness to phonemic cueing, although studied extensively in the aphasia population, have not been identified in the Alzheimer's disease population. In this study, four variables were analyzed in relation to successfulness of phonemic cueing: severity of dementia, confrontational naming ability, auditory comprehension, and speech fluency. All three language measures showed a significant positive correlation with cueing. Severity of dementia showed a significant inverse correlation with responsiveness to cueing and was the best predictor of successful use of cueing. It was concluded that phonemic cueing aided in label retrieval, problematic in the early stages of Alzheimer's disease, prior to significant erosion of semantic meaning.

Lexical decision and priming in Alzheimer's disease

Patients with probable Alzheimer's disease (AD) were no faster at making lexical decisions to targets preceded by a semantic prime than to those preceded by an unrelated prime, in contrast to the facilitatory effect of semantic primes for controls. Fewer errors were made by both subject groups on the targets that followed related items, indicating the preservation of associative relationships in AD. The AD patients and controls showed similar effects on lexical decision of repetition priming, word frequency, and the degree to which nonwords approximated real words. The abnormal priming effect in AD may stem from increased susceptibility to lateral inhibition in the semantic network.

Naming errors in healthy aging and dementia of the Alzheimer type

Naming errors were analyzed for healthy younger and older adults and patients with a diagnosis of senile dementia of the Alzheimer type (SDAT). Three types of errors were identified, varying in relatedness to the target word: near synonyms; semantically related naming errors; and unrelated naming errors. Older adults made relatively more related errors than did younger adults. SDAT patients were distinguished by the number of unrelated responses given. In addition, SDAT patients who scored within the normal range were identified by the high number of response attempts relative to the number of initial errors. We suggest that error patterns on naming tasks may potentially serve as clinical markers to distinguish healthy older persons with mild naming disorders from patients with SDAT.

Representation of semantic and spatial knowledge in Alzheimer's patients: implications for models of preserved learning in amnesia

Patients with Alzheimer's disease may exhibit severe, but variable patterns of cognitive deficits which can complicate and confound investigations of memory. Three patients are described with comparable levels of intellectual and memory abilities as assessed by the Wechsler scales. One patient (W) had a relatively circumscribed impairment of word-finding ability concurrent with intact visuospatial and constructional skill. Another patient (C) showed the opposite profile of abilities, while the third patient (G) exhibited deficits in both domains. All three patients were severely and globally amnesic when tested with traditional recall and recognition procedures. Patient W was able to demonstrate preserved semantic knowledge on a superordinate and category level but not for specific object attributes. Patient C demonstrated a remarkably preserved ability to generate and copy complex, meaningful, but not meaningless material. Corresponding profiles of preserved learning were revealed, but only under conditions that limited the demands on encoding and retrieval processes. Models were offered to account for these contrasting patterns of impairment. In addition, the possibility that medial temporal structures contribute to the ability to consciously reconstruct prior experiences was discussed.

Anomia in cerebral diseases

Naming performance was studied in demented patients, age-matched controls, left-hemisphere stroke patients with aphasia and right-hemisphere stroke patients. The experimental naming test compared four levels of perceptual difficulty and two language variables: word frequency and word length. Naming accuracy and error types were compared among subject groups. Perceptual difficulty influenced naming in the demented and right-hemisphere stroke patients, but not in aphasics and controls. Visual errors, likewise, characterized the former two groups. Semantically-related errors and circumlocutions characterized the naming of aphasic and demented patients, while phonemic errors were common only in aphasics. The results suggested differing patterns of anomia in different patient groups.

Subcortical dementia. Neuropsychology, neuropsychiatry, and pathophysiology

Subcortical dementia refers to a clinical syndrome characterised by slowing of cognition, memory disturbances, difficulty with complex intellectual tasks such as strategy generation and problem solving, visuospatial abnormalities, and disturbances of mood and affect. The syndrome was first described by Kinnier Wilson, but further progress in development of the concept has occurred only within the past ten years. Subcortical dementia occurs in degenerative extrapyramidal disorders and has also been identified in inflammatory, infectious, and vascular conditions. Histologic, metabolic, and neurochemical investigations implicate dysfunction primarily of subcortical neurotransmitter systems and subcortical structures or subcortical-frontal connections in the genesis of the syndrome. Subcortical dementia contrasts neuropsychologically and anatomically with disorders such as dementia of the Alzheimer type that affect primarily the cerebral cortex. The clinical characteristics of subcortical dementia reflect the interruption of fundamental functions (motivation, mood, timing, arousal) mediated by phylogenetically and ontogenetically early maturing structures.

Towards a behavioral typology of Alzheimer's patients

Neuropsychological test performance and estimates of regional rates of cortical glucose metabolism obtained via positron emission tomography are presented for patients with Alzheimer's disease (AD). Analyses of these data indicated the presence of distinct subgroups characterized by qualitatively different profiles of cognitive impairment and corresponding patterns of cerebral hypometabolism. No subgroup differences were noted with regard to age at onset or reported duration of symptoms. These findings indicate that, in a given individual, AD may initially invade a relatively circumscribed cortical region. Thus, although AD may constitute a single disease process, it does not result in a unitary neuropsychological syndrome.

Assessment of the accuracy of regression equations proposed for estimating premorbid intellectual functioning on the Wechsler Adult Intelligence Scale

This investigation examined the accuracy of regression equations proposed by Wilson et al. (1978) for estimating premorbid intellectual quotients (IQs) on the Wechsler Adult Intelligence Scale (WAIS). Actual Verbal, Performance, and Full Scale IQs in a sample of 69 neurologically normal adults were compared against their estimated premorbid levels. While the equations provided an adequate overall fit to the data, actual IQ values at the extremes of the WAIS Scales were found to be most susceptible to underestimation (high actual IQ values) or overestimation (low actual IQ values). The clinical importance of this finding and possible applications of the equations are discussed.

Controlled and automatic information processing in senile dementia: a review

The evidence on cognitive decline in senile dementia is reviewed with respect to the distinction between controlled and automatic processing. It is argued that controlled processing, which requires the attentional resources of the individual, declines in early senile dementia. However, automatic processing, which does not require attentional resources, is well maintained until late in the disorder. Implications of this view are drawn for the development of effective screening instruments which can be used for the early detection of dementia in the general population.

Retrieval from semantic memory in Alzheimer-type dementia

Retrieval from semantic memory, measured by tasks requiring subjects to name items from a given category, was studied in mild Alzheimer-type dementia (Mild-ATD) subjects, moderate-to-severe Alzheimer-type dementia (MS-ATD) subjects, and normal controls. Semantic retrieval performance was shown to be highly sensitive to both the presence and the severity of ATD. Retrieval from both semantic categories and letter categories showed differences in the rate of production of correct responses between subject groups. These rate differences were not due to differences in accessibility of low-dominance semantic category members or low-frequency letter category members. An increase in errors as well as a decrease in correct responses contributed to the performance deficits of the ATD subjects. Furthermore, the pattern of errors changed from Mild- to MS-ATD. Qualitative as well as quantitative differences were also observed in the performance of Mild- versus MS-ATD groups on a third type of semantic retrieval task--the supermarket task. As performance of the ATD subjects declined on these semantic retrieval tasks, so did their performance on other tasks assessing primarily attention, language, and memory. The findings are discussed in terms of the progressive breakdown in both attentional and semantic memory functions which are associated with ATD.

Dementia of the Alzheimer type. An inventory of diagnostic clinical features

An Inventory presenting characteristics useful in the clinical identification of dementia of the Alzheimer type (DAT) is presented. The Inventory includes aphasia, amnesia, abnormal cognition and visuospatial skills, inappropriate lack of concern, and normal motor functions. In a retrospective study of 50 consecutive dementia patients, the DAT Inventory correctly identified 100% of DAT subjects and 94% of non-DAT cases. Utilization of positive criteria can aid in the identification of DAT and can facilitate recognition of treatable illnesses masquerading as DAT.

Lexical retrieval in healthy aging

Lexical retrieval for common nouns and verbs was measured using 2 picture naming tests in 162 healthy female and male subjects aged 30 to 79 years. Responses were scored for correctness, responsivity to cueing, and response type. The ability to name both word types declined with age, especially after age 70 in healthy subjects. More errors were made on object names than action names, especially for older subjects. Subjects of all ages were equally able to utilize phonemic cues. With increasing age subjects produced more circumlocutions and fewer semantic errors. Response type difference need not reflect qualitative differences in lexical retrieval; rather, they reflect the quantitatively greater difficulty of the task for healthy older people as compared to younger adults. The naming difficulty for healthy aging, we conclude, is at the label retrieval stage.

Neuropsychological test performances and normal aging

This study was designed to assess the relevance of normal aging to performance in a variety of neuropsychological tests, in a wide range of age groups. The battery included tests of several cognitive abilities of varying complexity (attention, orientation, memory, self-regulation, categorial ability and so on). The results showed that some tests (Orientation, Attention, Digit Span, Naming, Block Design, Self-regulation, Calculation, Weigl) are not significantly affected by aging while in others performance clearly declines with age. However, the age at onset of the decline is far from uniform. In some tests (Logical Memory, delayed recall section of Supraspan Test, Hooper Test, Finger Tapping Test) it is manifest in early middle age while in others (Faces Recognition, Set Test, Reproduction of Geometric Designs) it does not appear until much later in life.

The Stroop color-word test: indicator of dementia severity

The Stroop color-word test was used to examine patterns of cognitive decline in Alzheimer-type dementia (ATD) and non-Alzheimer dementia. Slowing on color naming and word reading was observed, and was greater in moderate than in mild dementia subjects. However, error scores were unrelated to dementia type and severity. The Stroop interference effect, measured with reaction time, was high in individuals with mild ATD and mild non-Alzheimer dementia. In contrast, the more severely impaired ATD subjects showed less Stroop interference effect than mildly impaired subjects when the reaction time was adjusted for color naming performance. These findings are attributed to variation in speed-accuracy tradeoff for the patient groups due to differences in information processing deficits, linguistic impairment, and attitudes to errors. This study demonstrates the importance of partialling out underlying deficits for the understanding of complex cognitive processes in dementia.

Altered patterns of word associations in dementia and aphasia

The word associations of 38 demented, 17 aphasic, and 22 normal subjects were studied. Both normal and brain-injured subjects appear to make judgments about the grammatical class of the word stimulus. Certain stimulus words (especially nouns and adjectives) elicit paradigmatic responses whereas other words (especially verbs and adverbs) elicit syntagmatic responses. The mechanism producing syntagmatic responses seems relatively resistant to deterioration in dementia or aphasia. However, in dementia the mechanism that generates paradigmatic responses becomes progressively less efficient (possibly due to a loss of semantic markers) and consequently more random (idiosyncratic) responses emerge. Perseverative responses, inhibited in normal subjects, are more prevalent in dementia. Anomic aphasics show a pattern of word associations similar to that of subjects with mild dementia. Broca's aphasics, while making fewer paradigmatic associations than normals, retain enough self-monitoring mechanisms so that few idiosyncratic and perseverative responses are made while more null responses occur. Wernicke's aphasics show a marked shift away from a paradigmatic word association strategy, possibly due to an inability to access semantic markers or a true loss of these markers. Metalinguistic deficits (i.e., a failure to adopt an appropriate strategy) may also contribute to this shift away from paradigmatic associations. Furthermore, a disruption of self-monitoring mechanisms in Wernicke's aphasia leads to an increase in perseverative and idiosyncratic responses.

Recent advances in the neuropsychology of Alzheimer's disease

Memory, language, and visuospatial impairments are prominent neuropsychological deficits in Alzheimer's disease. The neuropsychological characteristics of Alzheimer's disease are unique, and contrast with those of other brain diseases. Neuropsychological study of patients with Alzheimer's disease may be useful in discovering the neuronal basis of cognitive processes, in differential diagnosis of dementia, and in evaluating treatment.

The naming disorder of dementia

Naming impairment is a common feature of the language disorder of dementia, yet agreement has not been reached on its mechanisms. In this study, the confrontation naming performance of twelve demented subjects was compared to that of age-matched controls. Naming deficits were studied in relation to overall language and cognitive dysfunction and analysed to assess the importance of both perceptual and linguistic factors. Naming dysfunction occurred even in mild dementia, in patients whose overall language function remained normal, and worsened in proportion to the degree both of language deficit and overall cognitive dysfunction. Perceptual difficulty and word frequency, but not word length, were important determinants of naming performance in demented patients.