Changes to the object recognition system in patients with dementia of the Alzheimer's type

Do DAT patients show category-specific deficits in object identification, and do they arise from semantic or visual damage? Participants decided whether line drawings of living and nonliving objects matched names at superordinate, basic, or subordinate levels. Patients were most impaired with superordinate decisions. Controls had most difficulty with subordinate decisions. No category-specific deficit was found with patients. Impaired superordinate decisions by the patients support semantic damage. If category-specific deficits arise from damaged semantics, they should have been found. Since they were not, and since patients performed subordinate decisions the best, a visual basis to category specificity is supported. Finally, a living advantage was found with normal observers which cannot be spurious due to differences in concept familiarity since living and nonliving objects were matched for this variable.     

Bender-Gestalt Test performance in senile dementia of the Alzheimer type

Bender-Gestalt Test performances of 144 persons with very mild, mild, or moderate senile dementia of the Alzheimer type (SDAT) and 96 healthy older adults ranging in age from 63 to 95 were compared. Total scores and error types according to the modified Hutt-Briskin scoring system are reported. The Bender-Gestalt Test does not appear to be useful in differentiating very mild or mild SDAT from normal aging.     

Primate learning tasks reveal strong impairments in patients with presenile or senile dementia of the Alzheimer type

Eight subjects with the likely diagnosis of presenile or senile dementia of the Alzheimer type were tested on two frequently used primate learning tasks: a concurrent object discrimination task and a delayed non-match-to-sample task. In addition, various tests for cognitive, mnemonic, perceptual, and language functions were applied. The results suggest a severe decline of the Alzheimer subjects in all measures when compared with 10 control subjects matched for age, gender, and education. The two animal learning tasks revealed strong impairments, thus demonstrating a high sensitivity for the detection and assessment of human amnesic disorders. Implications of these findings for human neuropsychological, and especially comparative neuropsychological, research are discussed.     

Pattern of semantic memory impairment in dementia of Alzheimer's type

The specific pattern of semantic memory impairment in patients with dementia of Alzheimer's type (DAT) remains unclear. Specifically, the presence of a category-specific deficit for biological concepts (reflected in anomia for these concepts) has been questioned. We studied 9 DAT patients using a semantic association judgement test in which they had to decide which of the two given words was most like a target word (e.g., lamb: goat, sheep). The 150 target words were drawn from 6 categories: animals, clothing and furniture, fruits and vegetables, tools, action verbs, and abstract nouns. Age- and education-matched control subjects performed equivalently (between 86 and 90% correct) in all categories. Compared to control subjects, DAT patients made significantly more errors in abstract and biological nouns, but not in verbs and man-made artifacts. This pattern of semantic memory impairment--a sparing of verbs and a selective deficit of nouns in the biological category--has been documented in patients with temporal lobe damage, suggesting a critical dysfunction in the temporal lobes of DAT.     

Characteristic patterns of word association responses in institutionalized elderly with and without senile dementia

This study examined the responses of 91 institutionalized elderly persons to the Goldfarb-Halpern Word Association Test (1981), Journal of Speech and Hearing Research, 24, 233–246. Subjects with senile dementia evidenced a characteristic pattern of responses which included marked reduction of paradigmatic responses, no decrease in syntagmatic responses, and a marked increase in unclassifiable and multiword responses not previously reported in the literature. The declines and increases appeared linear and progressive with severity of dementia. The pattern was distinct from that of any other adult group previously tested with this tool. Institutionalized elderly subjects without senile dementia performed similarly to previously tested noninstitutionalized elderly. Theoretical and clinical implications are discussed.     

Public discourse and the myth of religious speech

Critics of public religious speech have proposed various strategies for limiting the presence of religion in the public square, while proponents of public religious speech argue that such limitations constitute an infringement of the freedom of speech. For theoretical, practical, and ethical reasons, I argue for dismissing the category of ‘religious speech’, which rests on the erroneous assumption of a clear distinction between ‘the religious’ and ‘the secular’. ‘Religious speech’ should be regarded no differently from any other kind of speech; it therefore ought not to be subject to either special limitations or protections. Regarding religious speech as nothing other than free speech ensures the right of religious citizens publicly to express their views, while simultaneously preserving the right of other citizens to provide a critique to arguments that are framed in religious terms.     

The effects of age and dementia of the Alzheimer's type on phonological false memories

The authors conducted 3 experiments that examined the effects of age and dementia of the Alzheimer's type (DAT) on phonological false memories. In addition, the study was designed to investigate the role of inhibitory control in mediating phonological false memories. In Experiment 1, both young-old and old-old participants exhibited increased susceptibility to false remembering, compared with young adults. In Experiment 2, auditory Stroop interference was used as an index of inhibitory abilities and was found to account for a significant percentage of the variance in false recollection. Experiment 3 provided converging evidence for the importance of inhibitory control in phonological false memories by demonstrating that DAT patients are more susceptible to false recall and recognition than healthy older adults. The results are discussed within the inhibitory deficit framework of cognitive aging.     

Context processing and context maintenance in healthy aging and early stage dementia of the Alzheimer's type

Declines in the ability to process context information may represent a fundamental mechanism of age-related cognitive changes. Two components of context processing--activation/updating and maintenance--were examined in a sample of healthy younger and older adults, along with individuals suffering from early stage dementia of the Alzheimer's type (DAT). All older adult groups showed context activation/updating impairments, whereas context maintenance was only impaired in the oldest adults (age>75 years) and was further exacerbated in DAT individuals. The results suggest that context processing may be composed of functionally dissociable components and point to the utility of this construct in understanding the timecourse of cognitive decline in healthy and pathological aging.     

Evidence for a shrinking span of personal and present existence in dementia of the Alzheimer's type

Severely impaired episodic memory deprives patients with Alzheimer's disease (AD) of a sense of personal continuity in their daily lives, yet there are no tests that accurately measure this impairment. Recently, Zakzanis, Leach, and Moscovitch (1999) examined the integrity of memory function in terms of temporal continuity in a way that would engage the patient in everyday behavior, such as informal conversation, but still allow memory function to be quantified. The task allowed the measurement of the duration of continuous, conscious experience of the present and was therefore termed "span of temporal continuity (STC)." Given that we were able to document static and growing STCs, we wanted to know whether our measure could track progressive memory loss. Accordingly, we followed a patient we believed was in the very early stages of AD to measure the change of his STC longitudinally. Along with his STC, we present our neuropsychological and brain imaging findings over the course of the investigation.     

The semantic category effect increases with worsening anomia in Alzheimer's type dementia

A large number of patients (n=72) with probable Alzheimer's type dementia (DAT) and mild cognitive impairment (MCI) carried out a picture naming task which comprised stimuli from biological and nonbiological categories. The results were stratified into five ranges of overall naming ability. Every group except those with scores within the range of elderly normal individuals demonstrated better nonbiological naming than biological naming, an effect which increased with worsening impairment. In general, patients diagnosed with other dementia (n=15) did not fit well within the pattern of the DAT/MCI participants, except those known to have a significant semantic impairment. A category effect favoring nonbiological items appears to be robust and produce a predictable pattern across progressive levels of impairment in AD.     

Equivalent spatial location memory deficits in rats with medial septum or hippocampal formation lesions and patients with dementia of the Alzheimer's type

College students, healthy elderly subjects, patients diagnosed with mild or moderate dementia of the Alzheimer's type, as well as rats with small or large lesions of the medial septum (MS), dorsal hippocampal formation (DHF) or nucleus basalis magnocellularis (NBM) were tested on an item memory task for a five- or six-item list of varying spatial locations. Equivalent patterns of item memory deficits as a function of serial order position were observed in rats with small or large MS or DHF lesions and patients with mild or moderate dementia of the Alzheimer's type. No deficits were found for NBM-lesioned rats. The results provide support for the possibility that rats with MS and DHF lesions mimic the mnemonic symptomatology of patients with Alzheimer's disease.     

The role of the right hemisphere in speech act comprehension

In this research the role of the RH in the comprehension of speech acts (or illocutionary force) was examined. Two split-screen experiments were conducted in which participants made lexical decisions for lateralized targets after reading a brief conversation remark. On one-half of the trials the target word named the speech act performed with the preceding conversation remark; on the remaining trials the target did not name the speech act that the remark performed. In both experiments, lexical decisions were facilitated for targets representing the speech act performed with the prior utterance, but only when the target was presented to the left visual field (and hence initially processed by the RH) and not when presented to the right visual field. This effect occurred at both short (Experiment 1: 250 ms) and long (Experiment 2: 1000 ms) delays. The results demonstrate the critical role played by the RH in conversation processing.     

Self-referential tags in the discourse of people with Alzheimer's disease

In a study of the discourse of 100 people with Alzheimer's disease treated for 12 months with donepezil, we observed that, as a group, they used a form of tag, described here as a self-referential tag (SRT), 14 times more frequently than did caregivers. Patients use SRTs to check propositions dependent on episodic memory as in I haven't seen the doctor recently, have I? and to monitor information flow as in I told you that already, didn't I? Based on criteria developed for distinguishing checking from monitoring tags, we document the type and frequency of patients' SRT use in the ACADIE corpus and analyze these in relation to standard measures of cognitive function (Mini Mental State Exam and Alzheimer's Disease Assessment Scale-cognitive sub-scale) at baseline and 12 months. Patients using monitoring SRTs (N=31), with or without checking SRTs, show significantly better cognitive test scores at 12 months, than are seen in patients who never use tags (N=29), or who only use checking tags (N=40). SRT use may be an independent measure of potential treatment responsiveness.     

Semantic feature knowledge and picture naming in dementia of Alzheimer's type: a new approach

This study addresses continuing controversies concerning the nature of semantic impairment in early dementia of the Alzheimer type (DAT), and the relationship between conceptual knowledge and picture naming. A series of analyses of fine-grained feature knowledge data show that: (1) distinctive features of concepts were more vulnerable than shared; (2) the amount of attribute knowledge about a concept was associated reliably, and in a graded fashion, with the ability to name a picture of that item; (3) sensory features were differentially important in naming; and (4) the degree of disruption to different types of attribute knowledge did not vary between items from living and nonliving domains. These findings are discussed in the context of contemporary cognitive and computational models of semantic memory organisation.     

Contrasting speech patterns in apraxia of speech and phonemic paraphasia

This study was designed to determine if perceptual phonological analysis would reveal distinctions between patients with apraxia of speech and patients with phonemic paraphasic speech. Test findings from 10 Broca's aphasics with apraxia of speech were compared to findings from 10 paraphasic speakers (5 conduction and 5 Wernicke's aphasics). Several marked differences were revealed. Predominant locus of errors and relative difficulty of different classes of phonemic segments were significant discriminators. There was a nonsignificant trend for substituted phonemes to be further from target phonetically in the paraphasic patients. In addition, the two groups showed certain consistent differences in the types of errors they produced. Apraxic patients produced many errors of transitionalization, while sequencing errors were more typical of the patients with phonemic paraphasia. The findings are interpreted in relation to a neuropsychological model of speech. It is suggested that phonemic paraphasia represents a breakdown mainly in the retrieval of phonological word patterns, while apraxia of speech is characterized predominantly by a disturbance in encoding phonological patterns into appropriate speech movements.     

Divergent thinking in Alzheimer's and frontotemporal dementia

Twenty-three patients with mild dementia of the Alzheimer's type (DAT) or frontotemporal type (DFT) and age- and education-matched control subjects were administered tests of complex fluency involving divergent thinking and tests of letter, category, and figural fluency. The tests of complex fluency discriminated the dementia patients from control subjects more strongly than did the other fluency tests. The results suggest that divergent thinking as assessed by complex fluency tests is a cognitive domain that is impaired early in the course of dementia. The sensitivity of complex fluency tests compared to that of letter, category, and figural fluency tests may be related to greater demands for conceptualization in relating stimulus attributes to function and greater demands for flexible thinking during self-directed search processes.     

Linguistic authority and convention in a speech act analysis of pornography

Recently, several philosophers have recast feminist arguments against pornography in terms of Speech Act Theory. In particular, they have considered the ways in which the illocutionary force of pornographic speech serves to set the conventions of sexual discourse while simultaneously silencing the speech of women, especially during unwanted sexual encounters. Yet, this raises serious questions as to how pornographers could (i) be authorities in the language game of sex, and (ii) set the conventions for sexual discourse—questions which these speech act-theoretic arguments against pornography have thus far failed to adequately answer. I fill in this gap of the argumentation by demonstrating that there are fairly weak standards for who counts as an authority or convention-setter in sexual discourse. With this analysis of the underpinnings of a speech act analysis of pornography in mind, I discuss a range of possible objections. I conclude that (i) the endorsement of censorship by a speech act analysis of pornography competes with its commitment to the conventionality of speech acts, and, more damningly, that (ii), recasting anti-pornography arguments in terms of linguistic conventions risks an unwitting defence of a rapist's lack of mens rea—an intolerable result; and yet resisting this conclusion requires that one back away from the original claim to women's voices being ‘silenced’.