Possible selves of individuals with Alzheimer's disease

This study is one of the first to examine self-goals and their relationship to affect among individuals with Alzheimer's disease (AD). Using the construct of possible selves, the authors collected data from 50 participants with mild to moderate AD and 50 demographically similar cognitively intact older adults. Findings suggest a resourcefulness and flexibility of the self-system in response to the presence of dementia-related concerns. Positive affect was associated with family-related self-goals of AD participants, indicating particular importance of this domain. Some of these responses may represent goal modifications that result in a more satisfactory adjustment to the illness; further inquiry may lead to a better understanding of resiliency and quality of life in persons with AD.     

Predictors of burden in spouse caregivers of individuals with Alzheimer's disease

This study used the following model of distress: Distress = [Exposure to Stress + Vulnerability]/[Psychological and Social Resources]. The constructs in the model were operationalized as (a) distress in response to caregiver experiences (burden); (b) exposure to stress (care recipient functional impairment in activities of daily living [ADLs]); (c) vulnerability (caregiver health problems, anger, and anxiety); and (d) resources (coping, outlook on life, and social supports). Long-term burden (15-18 months after entry) was predicted by several baseline variables: burden, care recipient ADLs, vulnerability and resource variables, and specific interactions of burden, ADLs, vulnerability, and resource variables. The interactions showed that caregivers with high vulnerability and low resources had higher burden scores than caregivers with other combinations of these variables.     

Evaluation of prospective memory training for individuals with mild Alzheimer's disease

Prospective memory (PM) refers to the timely execution of a previously formed intention. PM deficits are one of the earliest measurable deficits in Alzheimer's disease (AD; Huppert & Beardsall, 1993) and yet, there has been little systematic research devoted to identifying ways in which these deficits can be compensated for or minimized. In this pilot study, individuals with mild AD participated in a new training program aimed at improving PM performance on an experimental PM task. PM training consisted of errorless learning and spaced retrieval techniques taught in six sessions in subjects' homes. Results showed that compared to untrained AD controls. AD patients who received PM training performed a PM task successfully across 7 weeks posttreatment (over 90% accuracy; controls 16-33% accuracy).     

Sensitivity to prosodic structure in left- and right-hemisphere-damaged individuals

An experiment was conducted in order to determine whether left- (LHD) and right-hemisphere-damaged (RHD) patients exhibit sensitivity to prosodic information that is used in syntactic disambiguation. Following the work of, a cross-modal lexical decision task was performed by LHD and RHD subjects, as well as by adults without brain pathology (NC). Subjects listened to sentences with attachment ambiguities with either congruent or incongruent prosody, while performing a visual lexical decision task. Results showed that each of the unilaterally damaged populations differed from each other, as well as from the NCs in terms of sensitivity regarding prosodic cues. Specifically, the RHD group was insensitive to sentence prosody as a whole. This was in contrast to the LHD patients, who responded to the prosodic manipulation, but in the unexpected direction. Results are discussed in terms of current hypotheses regarding the hemispheric lateralization of prosodic cues.     

Generalizing prosodic patterns by a non-vocal learning mammal

Prosody, a salient aspect of speech that includes rhythm and intonation, has been shown to help infants acquire some aspects of syntax. Recent studies have shown that birds of two vocal learning species are able to categorize human speech stimuli based on prosody. In the current study, we found that the non-vocal learning rat could also discriminate human speech stimuli based on prosody. Not only that, but rats were able to generalize to novel stimuli they had not been trained with, which suggests that they had not simply memorized the properties of individual stimuli, but learned a prosodic rule. When tested with stimuli with either one or three out of the four prosodic cues removed, the rats did poorly, suggesting that all cues were necessary for the rats to solve the task. This result is in contrast to results with humans and budgerigars, both of which had previously been studied using the same paradigm. Humans and budgerigars both learned the task and generalized to novel items, but were also able to solve the task with some of the cues removed. In conclusion, rats appear to have some of the perceptual abilities necessary to generalize prosodic patterns, in a similar though not identical way to the vocal learning species that have been studied.     

Temporal patterns of negative and positive behavior among nursing home residents with Alzheimer's disease

Although clinical observations suggest a late-day peak in disruptive behavior in persons with dementia, results from studies of temporal patterns of behavior are equivocal. This study used direct observation methods and systematic time sampling to examine temporal patterns of negative and positive behavior in 177 residents of 2 long-term care facilities with clinically diagnosed Alzheimer's disease (AD). The authors found small statistically significant diurnal variation in both negative and positive behavior, characterized by a curvilinear pattern with a single peak. This pattern was unaffected by seasonal differences in length of day, severity of cognitive impairment, level of behavior, or sleep disturbances. Time when behavior peaked differed by type of behavior and by facility, and there was substantial heterogeneity in behavior patterns.     

A characterization of the prosodic loss in Parkinson's disease

Prosodic contours in the verbal output of 30 patients with Idiopathic Parkinson's disease were contrasted to those of fifteen age-, sex-, and educationally matched normal subjects. All subjects were tested for language disorder, dementia, depression, and the comprehension of linguistic prosody. The striking disorder of prosody in Parkinson's disease relates to motor control, not to a loss of the linguistic knowledge required to make prosodic distinctions. It appears that prosody, language and the motor planning of speech are integrated at a basal ganglia level.     

Impaired processing of prosodic and musical patterns after right hemisphere damage

The distinction between the processing of musical information and segmental speech information (i.e., consonants and vowels) has been much explored. In contrast, the relationship between the processing of music and prosodic speech information (e.g., intonation) has been largely ignored. We report an assessment of prosodic perception for an amateur musician, KB, who became amusic following a right-hemisphere stroke. Relative to matched controls, KB's segmental speech perception was preserved. However, KB was unable to discriminate pitch or rhythm patterns in linguistic or musical stimuli. He was also impaired on prosodic perception tasks (e.g., discriminating statements from questions). Results are discussed in terms of common neural mechanisms that may underlie the processing of some aspects of both music and speech prosody.     

Semantic processing in patients with Alzheimer's disease

Ten patients with dementia of the Alzheimer type and 10 normal controls performed a lexical decision, semantic facilitation task. The performance of the patients differed from that seen in normals. A post hoc subdivision of the data suggested that the diviation from normality was not uniform throughout the patient population. Six of the 10 Alzheimer patients showed an advantage of related primes over unrelated primes, while 4 of the 10 were actually faster in the unrelated condition than in the related condition. Nevertheless, both group of Alzheimer patients showed lexical decision latency differences between unrelated and related prime words, suggesting that patients with Alzheimer's disease are sensitive to the semantic relationships between words.     

Different patterns of cognitive slowing produced by Alzheimer's disease and normal aging

Aging has previously been shown to produce a generalized proportional slowing of all cognitive operations. In contrast, the present results suggested that Alzheimer's disease produces a disproportionate reduction in the speed with which patients carry out one or more mental operations. The tasks that demented patients found particularly difficult involved either a self-directed search of their lexicon or the use of familiarity information.     

Word segmentation with universal prosodic cues

When listening to speech from one’s native language, words seem to be well separated from one another, like beads on a string. When listening to a foreign language, in contrast, words seem almost impossible to extract, as if there was only one bead on the same string. This contrast reveals that there are language-specific cues to segmentation. The puzzle, however, is that infants must be endowed with a language-independent mechanism for segmentation, as they ultimately solve the segmentation problem for any native language. Here, we approach the acquisition problem by asking whether there are language-independent cues to segmentation that might be available to even adult learners who have already acquired a native language. We show that adult learners recognize words in connected speech when only prosodic cues to word-boundaries are given from languages unfamiliar to the participants. In both artificial and natural speech, adult English speakers, with no prior exposure to the test languages, readily recognized words in natural languages with critically different prosodic patterns, including French, Turkish and Hungarian. We suggest that, even though languages differ in their sound structures, they carry universal prosodic characteristics. Further, these language-invariant prosodic cues provide a universally accessible mechanism for finding words in connected speech. These cues may enable infants to start acquiring words in any language even before they are fine-tuned to the sound structure of their native language.     

The attribute priming effect in patients with Alzheimer's disease

Experiments with semantic priming (SP) paradigms have documented early hypopriming in patients with AD when concepts are used as primes and attribute concept features as targets, suggesting that concept attributes are vulnerable to damage very early in the disease course. The aims of this study were to confirm early priming reduction in the attribute condition in patients with AD and to determine which of several semantic indexes (such as the level of distinctiveness, correlation or feature dominance of concept features) best predicts the priming effect size in AD. We administered an SP attribute condition paradigm to 20 mildly demented patients with AD and to 10 NCs. We used concept–attribute pairs for which normative data of semantic indexes relative to both concept primes (i.e., number, type, mean level of dominance, distinctiveness and correlation of features constituting the concepts) and target features (i.e., level of feature dominance, correlation and distinctiveness) were available. Results showed that compared to NCs, the AD group obtained very reduced priming facilitation. Furthermore, the item regression analyses showed that the priming decrement in the AD group was predicted by the feature dominance of the target in the related pairs; that is, the lower the target feature dominance, the lower the priming effect elicited. These results confirmed hypopriming in the attribute condition from the very early phase of AD and support the view that attributes which are more salient for the identification of a given concept are also those most resistant to semantic memory degradation in AD pathology.     

Semantic memory in Alzheimer's disease

Patients with Alzheimer's disease have been suggested to have a semantic memory impairment not present in the normal old. This article reviews the performance of Alzheimer patients on tests of various aspects of semantic memory, including word finding, knowledge of the semantic attributes, and associates of concepts, as well as their category membership. The effect that semantic context has on cognitive processes such as lexical and semantic priming and memory encoding is also reviewed. Finally, the ability of theoretical constructs such as implicit memory and automaticity to explain intertask variability in Alzheimer patients' semantic performance is discussed.     

Maze learning in Alzheimer's disease

Alzheimer's disease (AD) patients and normal elderly controls performed a block of 10 trials on a finger maze, followed by a 45-min period during which verbal learning measures were administered. Subjects then performed an additional 10 trials on the original maze, followed by 10 trials on a new maze. The AD patients and a subset of control subjects decreased mean completion time across Blocks 1 and 2, suggesting skill acquisition. Mean time on Block 3 was significantly less than mean time on Block 1, suggesting skill generalization. A subset of controls did not show the above pattern. The results of this study suggest that AD patients are able to acquire and generalize a cognitively mediated perceptual-motor skill.     

Confabulation in Alzheimer's disease.

Confabulation is present when memory is disturbed, but does it occur in Alzheimer's disease (AD) where memory abnormalities are often severe? In this study, confabulation was assessed prospectively in 26 AD patients and 15 normal elderly (NE) controls using a neuropsychological battery specifically designed to assess different types of memory errors. The results indicated that the AD group made significantly more verbal intrusions than the NE group. These findings provide evidence for the feasibility of eliciting confabulatory-type behavior during clinical assessment and support previous reports which have documented verbal intrusions as a common accompaniment of the memory impairment manifested by AD patients.     

Posture recognition in Alzheimer's disease

BACKGROUND: Apraxia is neurologically induced deficit in the ability perform purposeful skilled movements. One of the most common forms is ideomotor apraxia (IMA) where spatial and temporal production errors are most prevalent. IMA can be associated Alzheimer's disease (AD), even early in its course, but is often not identified possibly because the evaluation of IMA by inexperienced judges using performance tests is unreliable. The purpose of this study, therefore, is to learn if the Postural Knowledge Test (PKT), a praxis discrimination test that assesses knowledge of transitive (PKT-T subtest) and intransitive (PKT-I subtest) postures and does not require extensive training, is as sensitive and specific as the praxis performance tests. METHODS: We studied 15 subjects with probable AD as well as 18 age-matched controls by having them perform transitive and intransitive gestures to command and imitation, as well as having them discriminate between correct and incorrect transitive and intransitive postures. RESULTS: Overall on all tests, the control subjects performed better than those with AD. In addition all subjects had more trouble with transitive than intransitive gestures. Using a stepwise discriminative analysis, 81.8% of the subjects could be classified according to Group (94.4% of Controls, 66.7% of AD subjects). In this analysis, the PKT-T (transitive posture subtest) was the only measure that contributed to the discrimination of subjects. CONCLUSION: We found that having subjects select the correct transitive hand postures in this "booklet test" was more sensitive than grading their praxis performances even when using judges with extensive training. This suggests that this discrimination test might be an excellent means for diagnosing and screening patients for AD. The reason why recognition of transitive postures is relatively more difficult for our AD subjects is not known. Two possibilities are that the representations for intransitive movements are stronger than those for transitive movements, and hence, more resistant to degradation, or that intransitive acts are stored in parts of the brain not affected by AD.