Semantic Feature Disturbance in Alzheimer Disease: Evidence from an Object Decision Task.

BACKGROUND AND OBJECTIVE: It is widely held that semantic disturbance in Alzheimer disease (AD) involves the loss of distinctive features but the relative sparing of nondistinctive features. Many previous studies of semantic feature disturbance have used cognitively challenging tasks with verbal stimuli that allow for potential cognitive confounds. Our objective was to use a task with lower memory demands to investigate distinctive feature disturbance in AD. METHODS: We used an object decision task to compare the processing of distinctive and nondistinctive semantic features in people with AD and age-matched controls. The task included six conditions based on the relationship between each prime and target object. We tested the processing of distinctive and nondistinctive features by selectively altering distinctive and nondistinctive semantic features between prime and target pairs. RESULTS: Performance accuracy was significantly lower for participants with AD than for age-matched controls when distinctive features were manipulated, but no difference was found when nondistinctive features were manipulated. CONCLUSIONS: Our results provide evidence of semantic content disturbance in AD in the context of a task with low cognitive demands.

Evaluating the MESSAGE Communication Strategies in Dementia training for use with community-based aged care staff working with people with dementia: a controlled pretest-post-test study.

AIMS AND OBJECTIVES: The study aims to evaluate the effects of a communication skills training programme on community aged care staff's knowledge of communication support in dementia and on staff's care experience. BACKGROUND: Dementia can lead to impairments in communication. Therefore, quality community-based dementia care requires that staff be skilled communicators, equipped to facilitate interactions with people with dementia. The current investigation evaluated the effectiveness of the MESSAGE Communication Strategies in Dementia for Care Staff training programme with respect to knowledge of communication support and the staff/caregiver experience. DESIGN: A multi-centre controlled pretest/post-test design with randomised cohort allocation was used. Outcome measures were completed at baseline, immediately after training (training group only), and at three-month follow-up. METHODS: Thirty-eight care staff working in community aged care participated and completed all outcome measures (training = 22; control = 16).Training and control groups completed the following outcome measures: knowledge of communication support strategies, self-efficacy, preparedness to provide care, strain in nursing care and attitude to dementia care. Staff in the training group provided written feedback on the training. RESULTS: A significant improvement in knowledge scores from baseline was found for the training group both immediately after training and at three-month follow-up. There was also a significant training effect for self-efficacy and preparedness to provide care. No significant difference was found for the control group for any measure. No significant training effects were found for measures of strain or attitudes to dementia care. Feedback from staff suggests that the training was well received. CONCLUSIONS: The MESSAGE training was positively received by staff and had a significant effect on care staff knowledge, and confidence to provide care for people with dementia. RELEVANCE TO CLINICAL PRACTICE: The easily accessible multimedia training programme is well received by staff and has the potential to improve quality of care.

Balancing Self-Tracking and Surveillance: Legal, Ethical and Technological Issues in Using Smartphones to Monitor Communication in People with Health Conditions.

Smartphones are being used to track the health of individuals in their own environments. For example, a smartphone app could be used to monitor the impact and progression of Parkinson's disease, as well as indicate whether treatments may need to be adjusted, based on an analysis of voice and discourse. The app uses smartphone audio sensors to detect when conversations are taking place and activates an app to record the conversation. But what happens if a background conversation is also collected by the recording? The participants of the background conversation are unaware of and have not consented to the recording. Unauthorised recording could also raise legal issues under surveillance devices legislation and has ethical implications. It is a complex task to balance the potential benefits of self-tracking of health conditions to consumers and the health system, with the legalities and ethical issues related to privacy. The health-related monitoring industry is moving so rapidly that current legal and ethical processes and protocols may fail to balance these concerns. This article explores Australian legal and ethical perspectives on how to achieve the potential benefits of these technological approaches while preserving privacy.

A dual task priming investigation of right hemisphere inhibition for people with left hemisphere lesions.

BACKGROUND: During normal semantic processing, the left hemisphere (LH) is suggested to restrict right hemisphere (RH) performance via interhemispheric suppression. However, a lesion in the LH or the use of concurrent tasks to overload the LH's attentional resource balance has been reported to result in RH disinhibition with subsequent improvements in RH performance. The current study examines variations in RH semantic processing in the context of unilateral LH lesions and the manipulation of the interhemispheric processing resource balance, in order to explore the relevance of RH disinhibition to hemispheric contributions to semantic processing following a unilateral LH lesion. METHODS: RH disinhibition was examined for nine participants with a single LH lesion and 13 matched controls using the dual task paradigm. Hemispheric performance on a divided visual field lexical decision semantic priming task was compared over three verbal memory load conditions, of zero-, two- and six-words. Related stimuli consisted of categorically related, associatively related, and categorically and associatively related prime-target pairs. Response time and accuracy data were recorded and analyzed using linear mixed model analysis, and planned contrasts were performed to compare priming effects in both visual fields, for each of the memory load conditions. RESULTS: Control participants exhibited significant bilateral visual field priming for all related conditions (p < .05), and a LH advantage over all three memory load conditions. Participants with LH lesions exhibited an improvement in RH priming performance as memory load increased, with priming for the categorically related condition occurring only in the 2- and 6-word memory conditions. RH disinhibition was also reflected for the LH damage (LHD) group by the removal of the LH performance advantage following the introduction of the memory load conditions. CONCLUSIONS: The results from the control group are consistent with suggestions of an age related hemispheric asymmetry reduction and indicate that in healthy aging compensatory bilateral activation may reduce the impact of inhibition. In comparison, the results for the LHD group indicate that following a LH lesion RH semantic processing can be manipulated and enhanced by the introduction of a verbal memory task designed to engage LH resources and allow disinhibition of RH processing.

Memory and communication support strategies in dementia: effect of a training program for informal caregivers.

BACKGROUND: People with dementia have a range of needs that are met by informal caregivers. A DVD-based training program was developed using research-based strategies for memory and communication in dementia. The effectiveness of the training on the caregiver experience and the well-being of the person with dementia was evaluated. METHODS: A pre-test/post-test controlled trial was undertaken with caregiver-care-recipient dyads living in the community. Measures of the carers' knowledge of memory and communication strategies, burden, positive perceptions of caregiving, and perceptions of problem behaviors were taken pre- and three months post-intervention. The depression and well-being of the person with dementia were also evaluated. Satisfaction with the training and feedback were measured. RESULTS: Twenty-nine dyads (13 training group, 16 control group) participated. Bonferroni's correction was made to adjust for multiple comparisons, setting α at 0.00385. A significant improvement was found in caregivers' knowledge for the training group compared to the control group (p = 0.0011). The training group caregivers reported a reduction in the frequency of care recipient disruptive behaviors (p = 0.028) and increased perceptions of positive aspects of caregiving (p = 0.039), both at a level approaching significance. The training group care recipients had increased frequency of verbally communicated depressive behaviors at a level approaching significance (p = 0.0126). The frequency of observed depressive behaviors was not significantly different between groups. CONCLUSIONS: This approach to training for caregivers of people with dementia appears promising for its impact on knowledge and the caregiving experience. Further research could monitor the impact of the training on broader measures of depression and well-being, with a larger sample.

We are not educating the future clinical health professional workforce adequately for e-health competence: findings of an Australian study.

This paper reports on a national study of the present approaches in Australian tertiary education, to preparing future clinical health professionals to work competently in an increasingly e-health enabled healthcare sector. The argument for increasing clinical health professionals' knowledge about e-health and health informatics has been advanced repeatedly over past decades in Australia and elsewhere. However, peer-reviewed accounts of good practice in implementing and evaluating e-health education in health profession degrees anywhere are scarce. Our study reports on surveying approximately 100 degree coordinators in 40 clinical health professions in 30 universities across Australia. It finds that currently, teaching and assessment of future clinical health professionals does not ensure that Australia will have a clinical workforce that is adequately professionally empowered to work with e-health. This paper provides important baseline data for planning improvements to e-health education for Australia's future clinical health professionals.

Acute nicotine enhances strategy-based semantic processing in Parkinson's disease.

Nicotinic mechanisms may play a role in the cognitive deficits of Parkinson's disease (PD). Recently, on a cognitively demanding strategy-based priming task, nicotine selectively affected controlled semantic processing in young adult non-smokers as reported by Holmes et al. (International Journal of Neuropsychopharmacology 11, 389-399, 2008). Such controlled semantic processing is compromised in PD. This study investigated the effects of acute transdermal nicotine on controlled semantic processing in non-smokers with PD (n = 10) and non-smoking matched controls (n = 16) using a strategy-based semantic priming paradigm. Transdermal nicotine patches (7 mg/24 h) were administered in a double-blind, placebo-controlled, crossover design. Participants were instructed to expect target words from specified semantic categories based on the primes, while unexpected targets were also presented. Priming conditions included those concurring with trained expectations (expected-related and expected-unrelated), those which did not (unexpected-related and unexpected-unrelated), and neutral-baseline conditions. Controls evidenced significant expectancy effects (i.e. reaction-time differences for expected vs. unexpected conditions) under both drug states. An expectancy effect was not evident for PD under placebo due to a lack of reaction-time slowing for unexpected conditions. However, under nicotine an expectancy effect was present for PD at a level comparable to controls. Overall the findings indicate that nicotine can improve impaired controlled semantic processing in PD possibly via enhanced expectancy or inhibitory mechanisms.

Memory and communication support in dementia: research-based strategies for caregivers.

BACKGROUND: Difficulties with memory and communication are prominent and distressing features of dementia which impact on the person with dementia and contribute to caregiver stress and burden. There is a need to provide caregivers with strategies to support and maximize memory and communication abilities in people with dementia. In this project, a team of clinicians, researchers and educators in neuropsychology, psychogeriatrics, nursing and speech pathology translated research-based knowledge from these fields into a program of practical strategies for everyday use by family and professional caregivers. METHODS: From the available research evidence, the project team identified compensatory or facilitative strategies to assist with common areas of difficulty, and structured these under the mnemonics RECAPS (for memory) and MESSAGE (for communication). This information was adapted for presentation in a DVD-based education program in accordance with known characteristics of effective caregiver education. RESULTS: The resultant DVD comprises (1) information on the nature and importance of memory and communication in everyday life; (2) explanations of common patterns of difficulty and preserved ability in memory and communication across the stages of dementia; (3) acted vignettes demonstrating the strategies, based on authentic samples of speech in dementia; and (4) scenarios to prompt the viewer to consider the benefits of using the strategies. CONCLUSION: Using a knowledge-translation framework, information and strategies can be provided to family and professional caregivers to help them optimize residual memory and communication in people with dementia. Future development of the materials, incorporating consumer feedback, will focus on methods for enabling wider dissemination.

Conversations between carers and people with schizophrenia: a qualitative analysis using leximancer.

We examined conversations between people with schizophrenia (PwS) and family or professional carers with whom they interacted frequently. We allocated PwS to one of two communication profiles: Low-activity communicators talked much less than their conversational partners, whereas high-activity communicators talked much more. We used Leximancer text analytics software to analyze the conversations. We found that carers used different strategies to accommodate to the PwS's behavior, depending on the PwS's communication profile and their relationship. These findings indicate that optimal communication strategies depend on the PwS's conversational tendencies and the relationship context. They also suggest new opportunities for qualitative assessment via intelligent text analytics technologies.

Impaired semantic inhibition during lexical ambiguity repetition in Parkinson's disease.

Impairments of semantic processing and inhibition have been observed in Parkinson's disease (PD), however, the consequences of faulty meaning selection and suppression have not been considered in terms of subsequent lexical processing. The present study employed a lexical ambiguity repetition paradigm where the first presentation of an ambiguity paired with a target biasing its dominant or subordinate meaning (e.g., bank - money or bank - river) was followed after several intervening trials by a presentation of the same ambiguity paired with a different target that biases the same (congruent) or a different (incongruent) meaning to that biased on the first presentation. Meaning dominance (dominant or subordinate weaker meanings) and interstimulus interval (ISI) were manipulated. Analyses conducted on the second presentation indicated priming of congruent meanings and no priming for the incongruent meanings at both short and long ISIs in the healthy controls, consistent with suppression of meanings competing with the representation biased in the first presentation. In contrast, the PD group failed to dampen activation for the incongruent meaning at the long ISI when the first presentation was subordinate. This pattern is consistent with an impairment of meaning suppression which is observed under controlled processing conditions and varies as a function of meaning dominance of the first presentation. These findings further refine our understanding of lexical-semantic impairments in PD and suggest a mechanism that may contribute to discourse comprehension impairments in this population.

Semantic activation in Parkinson's disease patients on and off levodopa.

Research suggests that dopamine may exert a neuromodulatory influence on automatic spreading activation within semantic networks. In order to investigate the influence of dopamine depletion on semantic activation in Parkinson's disease (PD), nine patients with PD performed a lexical decision task when on and off levodopa medication. Eleven healthy controls matched to the PD patients in terms of sex, age and education also participated in the study. Both directly related word pairs (e.g., tiger - stripe) and indirectly related word pairs (word pairs related via a mediating word, e.g., chalk - black) were used to measure semantic activation across stimulus onset asynchronies (SOAs) of 270msec, 520msec and 1020msec. Analysis of variance statistics revealed that the activation of directly related and indirectly related targets was slower for the PD group relative to the control group. Within group comparisons revealed further changes to semantic activation in PD patients off medication, with no activation of directly or indirectly related target words evident in PD patients off medication. These results further clarify the nature of dopamine's neuromodulatory influence on semantic activation, and suggest that the nature of altered semantic activation in PD may depend on the magnitude of dopamine depletion.

Verbal fluency, semantics, context and symptom complexes in schizophrenia.

Lexical-semantic access and retrieval was examined in 15 adults diagnosed with schizophrenia and matched controls. This study extends the literature through the inclusion of multiple examinations of lexical-semantic production within the same patient group and through correlating performance on these tasks with various positive and negative clinical symptoms. On tasks of verbal fluency, meaning generation, sentence production using contextual information and confrontation naming, participants with schizophrenia made significantly more semantic errors on naming tasks; produced fewer meanings for homophones; produced fewer items on semantic, phonological, cued and switching fluency tasks; and produced more errors on sentence production tasks when compared to healthy controls. Significant correlations were also observed between ratings of psychomotor poverty and measures of semantic production and mental inflexibility. This study has provided additional evidence for deficits in lexical-semantic retrieval which are not due to underlying semantic store degradation, do not involve phonological based retrieval, and at the level of sentence generation appear to vary as a function of the contextual constraints provided.

Conversational trouble and repair in dementia: Revision of an existing coding framework.

A decline in the effectiveness of everyday conversation is often observed for people with dementia. This study explored conversational trouble and repair between people with dementia residing in residential care and professional care staff. The aim was to examine the utility of an existing conversational trouble and repair framework by Watson, Carter and Chenery (1999) in a comparatively larger sample. Twenty conversations were coded for dementia-specific trouble and repair; however, the original framework could not adequately accommodate the variety of trouble and repair within the dataset. The data was subsequently used to inform a revised framework, which captures a wide spectrum of trouble and repair in dementia and offers more precise codes to researchers and clinicians working with this clinical population. Examples of divergent coding strategies between the original and revised framework are provided as well as examples of trouble and repair patterns observed in both carers and people with dementia.

Estimation of neuronal firing rates with the three-state biological point process model.

In the subcortex of the human brain, neuronal firing events are stochastic and the inter-arrival times of action potentials (APs) are highly irregular. It has been shown that stimulation of the subthalamic nucleus (STN), a small subcortical structure located within the basal ganglia, can help ameliorate the motor symptoms associated with Parkinson's disease (PD). However, success of image guided stereotactic surgery is reliant upon the refinement of the anatomic target (in this case the STN) based on micro-electrode recordings (MERs) of background activity and firing rate. In practice MERs must be analysed on-line and in real-time. Currently, the most common method of performing on-line MER analysis is a manual thresholding procedure. However, this is subjective in nature and often complicated by the presence of variable amounts of background noise. Therefore, in this paper, we present an automated adaptive thresholding technique, based on a modified 'top-hat' operator, which detects APs exceeding the local background activity. We then go on to model these inter-arrival times using a coupled Poisson process that provides improved estimates of both inter-burst and intra-burst neuronal firing activity in the STN.

The basal ganglia circuits, dopamine, and ambiguous word processing: a neurobiological account of priming studies in Parkinson's disease.

Research into the processing of lexical ambiguities has provided a valuable paradigm for investigating the functional architecture of the language processing system in normal and neurologically impaired populations and specifically, how basal ganglia circuits and the neurotransmitter dopamine may act to enhance and/or suppress various meanings relative to the context in which the lexical ambiguity appears. In this review, we develop the hypothesis that an integrated basal ganglia thalamocortical circuit linking the striatum and inferior frontal cortex is involved in the enhancement and suppression of ambiguous word meanings when a lexical ambiguity is presented within a linguistic context. Reference to behavioral, neurophysiological, and neurochemical studies of subcortical function in both healthy populations and people with Parkinson's disease will be used to provide further support for the proposal that the subcortex is integrally involved in ambiguous word processing.

Subthalamic stimulation affects homophone meaning generation in Parkinson's disease.

Deep brain stimulation (DBS) of the subthalamic nucleus (STN) in individuals with Parkinson's disease (PD) has often been associated with reduced verbal fluency performance. This study aimed to directly assess semantic switching as a function of STN stimulation in PD participants with the Homophone Meaning Generation Test (HMGT). Seventeen participants with PD who had received STN DBS completed the HMGT in on and off stimulation conditions. Twenty-one non-neurologically impaired participants acted as controls. PD participants (in both on and off stimulation conditions) generated significantly fewer meanings than control participants and consistent with the previous reports of verbal fluency impairment, PD participants produced fewer definitions in the on stimulation condition. PD participants (in both on and off stimulation conditions) also had greater difficulty generating definitions for nonhomographic homophones compared with homographic homographs. The results of this study indicate that STN stimulation exacerbates impairment in semantic switching.

Semantic and affective priming as a function of stimulation of the subthalamic nucleus in Parkinson's disease.

Lexical-semantic and emotional processing deficits have been associated with Parkinson's disease. This study investigated automatic and controlled lexical-semantic processing, the automatic activation of emotional evaluations, and the processing of words conveying negative and neutral emotional connotations in a combined affective and semantic priming paradigm. Eighteen participants with Parkinson's disease who had undergone surgery for deep brain stimulation (DBS) of the subthalamic nucleus (STN) completed a lexical decision task at short and long stimulus onset asynchronies (SOAs), during on and off stimulation conditions. Nineteen non-neurologically impaired participants acted as controls. The results indicated that automatic lexical-semantic and emotional evaluative processes are unimpaired in Parkinson's disease as reflected in the presence of comparable semantic and affective priming effects at the short SOA in on and off stimulation conditions compared with healthy controls. In contrast, participants with Parkinson's disease in the off stimulation condition showed a pattern of aberrant controlled lexical-semantic processing as evidenced by a lack of semantic priming effects at the long SOA condition. Controlled semantic priming was present, however, when the participants with Parkinson's disease were receiving stimulation of the STN, suggesting that STN stimulation modulates basal ganglia-thalamocortical circuits involved in such processes. Finally, delayed reaction times for negatively valenced targets compared with neutrally valenced targets was evident in participants with Parkinson's disease in the on stimulation condition and control participants, but not for participants with Parkinson's disease in the off stimulation condition, suggesting that the incidental evaluation of negatively versus neutrally valenced words in Parkinson's disease is modulated by basal ganglia-thalamocortical circuits.

The explicit learning of new names for known objects is improved by dexamphetamine.

A randomised, double-blind, placebo-controlled, between subjects study design (N=37) was used to investigate the effects of dexamphetamine on explicit new name learning. Participants ingested 10mg of dexamphetamine or placebo daily over 5 consecutive mornings before learning new names for 50 familiar objects plus fillers. The dexamphetamine group recognised and recalled the new names more accurately than the placebo group over the 5 days and 1 month later. Word learning success was not associated with baseline neuropsychological performance, mood, cardiovascular arousal, or sustained attention. These results may have implications for the pharmacological treatment of acquired naming difficulties.

Toward the Development of SMART Communication Technology: Automating the Analysis of Communicative Trouble and Repair in Dementia.

BACKGROUND AND OBJECTIVES: Communication difficulties have been reported as one of the most stress-inducing aspects of caring for people with dementia. Notably, with disease progression comes an increase in the frequency of communication difficulty and a reduction in the effectiveness of attempts to remedy breakdowns in communication. The aim of the current research was to evaluate the utility of an automated discourse analysis tool (i.e., Discursis) in distinguishing between different types of trouble and repair signaling behaviors, demonstrated within conversations between people with dementia and their professional care staff. RESEARCH DESIGN AND METHODS: Twenty conversations between people with dementia and their professional care staff were human-coded for instances of interactive/noninteractive trouble and typical/facilitative repair behaviors. Associations were then examined between these behaviors and recurrence metrics generated by Discursis. RESULTS: Significant associations were identified between Discursis metrics, trouble-indicating, and repair behaviors. DISCUSSION AND IMPLICATIONS: These results suggest that discourse analysis software is capable of discriminating between different types of trouble and repair signaling behavior, on the basis of term recurrence calculated across speaker turns. The subsequent recurrence metrics generated by Discursis offer a means of automating the analysis of episodes of conversational trouble and repair. This achievement represents the first step toward the future development of an intelligent assistant that can analyze conversations in real time and offers support to people with dementia and their carers during periods of communicative trouble.

Lexical-semantic inhibitory mechanisms in Parkinson's disease as a function of subthalamic stimulation.

Inhibitory control may be affected by Parkinson's disease (PD) due to impairment within the non-motor basal ganglia-thalamocortical circuits. The present study aimed to identify the effects of chronic stimulation of the subthalamic nucleus (STN) on lexical-semantic inhibitory control. Eighteen participants with PD who had undergone surgery for deep brain stimulation (DBS) of the STN, completed a picture-word interference (PWI) task and the Hayling test in on and off stimulation conditions. The results of PD participants were compared with 21 non-neurologically impaired control participants. PD participants performed no differently from controls on the PWI task, and no significant differences between on and off stimulation conditions were revealed, therefore suggesting that PD participants are not impaired in lexical-semantic interference control. In contrast, in the off stimulation condition, PD participants had significantly delayed reaction times and increased errors on the inhibition section of the Hayling test compared with the STN stimulation condition and control participants. These results suggest that PD patients are impaired in aspects of inhibitory control that are dependent on behavioural inhibition (such as the suppression of prepotent responses) and selection from competing alternatives without the presence of external cues. Furthermore, STN stimulation acts to restore these behavioural inhibitory processes.