Laura Brennan

Association Between Cognition and Function in Patients With Parkinson Disease With and Without Dementia

Patients with Parkinsons disease (PD) often have cognitive deficits from the time of diagnosis. Except in patients with dementia, the impact of cognitive symptoms on daily function is not well documented. This study had two objectives: (1) to determine the functional significance of cognitive deficits in nondemented patients with PD and (2) to assess the sensitivity of two measures of global cognitive abilities to identify individuals with impaired ADL function. One hundred eleven subjects with PD and a range of cognitive abilities were included. Of these, 20 were diagnosed with PDD. All subjects were assessed with the Mattis Dementia Rating Scale to two (DRS‐2) and the Mini‐Mental State Examination (MMSE). ADL function was reported by an informant using the Alzheimers Disease Cooperative Study Activities of Daily Living Inventory (ADCS‐ADL). The ability of the DRS‐2 and MMSE to capture the impact of cognitive impairment on ADL function was assessed in the entire cohort and in subsets of nondemented individuals. After adjustment for covariates, cognition as measured by the DRS‐2 was strongly related to ADL function in the entire cohort (partial correlation coefficient = 0.55, P < 0.001). The association remained strong when only nondemented subjects were included (r = 0.42, P < 0.001). The DRS‐2 was significantly more accurate than the MMSE, particularly for detecting milder degrees of ADL impairment (ROC area = 0.87 vs. 0.75, P = 0.0008). Cognition is associated with impairment in ADL function, even in nondemented patients with PD. However, sensitive cognitive assessment measures may be needed to identify these functionally relevant impairments.

Characterization of Everyday Functioning in Mild Cognitive Impairment: A Direct Assessment Approach

Aims: To evaluate the degree and pattern of functional difficulties in mild cognitive impairment (MCI) via direct observation of everyday task performance. Methods: MCI (n = 25), mild Alzheimer’s disease (AD; n = 25), and control (n = 18) participants performed three everyday tasks of increasing complexity. Results: Although caregivers reported no functional difficulties in MCI, direct observation measures of overall impairment and total errors showed MCI participants performed worse than controls, but better than AD participants, even on simple tasks. MCI and control participants exhibited significantly more difficulty performing steps accurately (i.e. commission errors) than completing task steps (i.e. omission errors), but AD participants showed an even distribution of commissions and omissions. Conclusions: Diagnostic criteria for MCI should specify mild functional deficits due to the inefficient and imprecise execution of task steps. Functional deficits characterized by omission of major task segments may indicate a diagnosis of dementia.

Coffee With Jelly or Unbuttered Toast: Commissions and Omissions Are Dissociable Aspects of Everyday Action Impairment in Alzheimer's Disease

Relative to our understanding of the memory and language deficits associated with Alzheimers disease (AD), little is known about problems with everyday action performance (i.e., meal preparation, grooming). The resource theory proposes that everyday action problems are best explained by a unitary deficit in general cognitive resources. However, recent research suggests that omission and commission errors may reflect dissociable aspects of action impairment, with only omissions associated with resource limitations. This study examined everyday action performance in 70 participants with AD who also underwent a neuropsychological evaluation. First, correlation and principal component analyses were performed to examine the construct(s) that might explain everyday action impairment. Second, relations between everyday task component(s) and neuropsychological tests were examined by using correlation and regression analyses. Third, differences in everyday action error patterns were examined among participants of comparable overall impairment levels. Results showed omission and commission errors were uncorrelated and distinct components of everyday action performance, predicted by different neuropsychological tests, and differentially distributed even among participants with comparable overall impairment.

Environmental Adaptations Improve Everyday Action Performance in Alzheimer's Disease: Empirical Support From Performance-Based Assessment

Neuropsychologists often recommend that patients with dementia and their caregivers use environmental adaptations to improve everyday functioning. Although these recommendations are intuitive (e.g., reduce clutter), most have never been experimentally tested. This study examined whether and how environmental adaptations improved everyday action in Alzheimers disease (AD). Forty-six outpatients completed the Naturalistic Action Test (NAT; M. F. Schwartz, L. J. Buxbaum, M. Ferraro, T. Veramonti, & M. Segal, 2003), which requires completion of 3 everyday tasks. The NAT was administered under 2 conditions: standard and user centered. The standard NAT followed the procedures of the manual; object placement was standardized, but objects were not meaningfully arranged on the tabletop. In the user-centered NAT, objects were arranged in the order needed in the task, and a visual cue to monitor performance was placed on the table. These conditions were counterbalanced across participants. The user-centered condition improved performance on all NAT items and reduced commission and omission error rates. However, post hoc examination of commission error types showed improvement of substitution and off-task errors but no difference in anticipation and perseveration errors. Thus, environmental adaptations improved everyday performance in AD by facilitating task accomplishment, object selection, and task-congruent actions.

Everyday Action Impairment in Parkinson's Disease Dementia

This study examined everyday action impairment in participants with Parkinsons disease dementia (PDD) by comparison with participants with Parkinsons disease-no dementia (PD) or Alzheimers disease (AD) and in reference to a neuropsychological model. Participants with PDD (n = 20), PD (n = 20), or AD (n = 20) were administered performance-based measures of everyday functioning that allowed for the quantification of overall performance and error types. Also, caregiver ratings of functional independence were obtained. On performance-based tests, the PDD group exhibited greater functional impairment than the PD group but comparable overall impairment relative to the AD group. Error patterns did not differ between PDD and PD participants but the PDD group demonstrated a higher proportion of commission errors and lower proportion of omission errors relative to the AD group. Hierarchical regression analyses showed omission errors were significantly predicted by neuropsychological measures of episodic memory, whereas commission errors were predicted by both measures of general dementia severity (MMSE) and executive control. Everyday action impairment in PDD differs quantitatively from PD but qualitatively from AD and may be characterized by a relatively high proportion of commission errors-an error type associated with executive control deficits. (JINS, 2012, 18, 1-12).

The impact of goal cues on everyday action performance in dementia

Everyday action performance is impaired as a consequence of dementia. Omissions (i.e., not performing task steps) are a frequent source of error in everyday tasks among dementia patients. External cues or notes are often suggested to improve everyday functioning and might specifically address omission errors; however, the efficacy of such strategies has not been evaluated. Thus, the primary aim of this study was to assess the efficacy of goal cues (i.e., reminders of everyday task objectives) for improving dementia patients everyday action performance. Forty-four participants with mild to moderate dementia were administered the Naturalistic Action Test (NAT), a performance-based test that includes three everyday tasks. After participants indicated that they had completed each task, they were presented with a cue card restating the task goals. Videotapes were used to code task performance as well as responses to the cues. Most participants checked their work and showed significant improvement in task accomplishment/omission errors, but not commission errors, after the cues. However, effect sizes for the differences were small, and the proportion of cases in the impaired range did not differ before versus after the cues. Therefore, although statistically significant, we concluded that the goal cues did not meaningfully or clinically improve everyday functioning.

Neuropsychological Syndromes Associated with Alzheimer's/Vascular Dementia: A Latent Class Analysis

BACKGROUNDnEpidemiologic autopsy studies show mixed Alzheimers disease (AD)/vascular pathology in many patients. Moreover, clinical research shows that it is not uncommon for AD and vascular dementia (VaD) patients to be equally impaired on memory, executive, or other neurocognitive tests. However, this clinical heterogeneity has not been incorporated into the new diagnostic criteria for AD (Dubois et al., 2010; McKhann et al., 2011).nnnOBJECTIVEnThe current research applied Latent Class Analysis (LCA) to a protocol of six neuropsychological parameters to identify phenotypic subtypes from a large group of AD/VaD participants. Follow-up analyses examined difference between groups on neuroradiological parameters and neuropsychological measures of process and errors.nnnMETHODSn223 AD/VaD patients were administered a comprehensive neuropsychological protocol. Measures of whole brain and hippocampal volume were available for a portion of the sample (n = 76).nnnRESULTSnLCA identified four distinct groups: moderate/mixed dementia (n = 54; 24.21%), mild/mixed dementia (n = 91; 40.80%); dysexecutive (n = 49, 21.97%), and amnestic (n = 29, 13.00%). Follow-up analyses comparing the groups on neuropsychological process and error scores showed that the dysexecutive group exhibited difficulty sustaining mental set. The moderate/mixed group evidenced pronounced impairment on tests of lexical retrieval/naming along with significant amnesia. Amnestic patients also presented with gross amnesia, but showed relative sparing on other neuropsychological measures. Mild/mixed patients exhibited milder memory deficits that were intermediary between the amnestic and moderate/mixed groups.nnnCONCLUSIONSnThere are distinct neuropsychological profiles in patients independent of clinical diagnosis, suggesting that the two are not wholly separate and that this information should be integrated into new AD diagnostic paradigms.

A quantitative meta-analysis of olfactory dysfunction in mild cognitive impairment

Background The connection between Alzheimers disease (AD) and olfactory deficits is well documented and further, alterations in olfactory functioning may signal declines in functions associated with dementia. The aim of the present comprehensive meta-analysis was to investigate the nature of olfactory deficits in mild cognitive impairment (MCI). Methods Articles were identified through computerised literature search from inception to 30 June 2016 using PubMed, MEDLINE and PsychInfo databases. In order to control for differences in sample size during effect size computation, studies were weighted according to their inverse variance estimates. Results 31 articles (62 effects) were identified, which included 1993 MCI patients and 2861 healthy older adults (HOA). Included studies contrasted odour identification, discrimination, detection threshold and/or memory between cases and controls. Moderate to large and heterogeneous effects were seen for olfactory deficits in MCI relative to HOA (d=−0.76, 95% CI −0.87<δ<−0.64). Moderator analysis revealed that tests of odour identification yielded larger effect sizes than those of odour detection threshold or memory. In addition, a potential interaction between age and sex was observed, with male patients carrying a larger burden of olfactory deficit and older female patients performing better on olfactory tests. Conclusions and relevance Olfactory deficits are present and robust in MCI. Odour identification is most impaired in MCI, which parallels the most prominent sensory deficit seen in AD. As such, a simple-to-administer test of odour identification warrants inclusion in the screening of individuals at risk for developing AD.

The Penn Parkinson's Daily Activities Questionnaire-15: Psychometric properties of a brief assessment of cognitive instrumental activities of daily living in Parkinson's disease *

INTRODUCTIONnTo describe the psychometric properties of the Penn Parkinsons Daily Activities Questionnaire-15 (PDAQ-15), a 15-item measure of cognitive instrumental activities of daily living for Parkinsons disease (PD) patients derived from the original 50-item PDAQ.nnnMETHODSnPDAQ-15 items were chosen by expert consensus. Knowledgeable informants of PD participants (n = 161) completed the PDAQ-15. Knowledgeable informants were defined as an individual having regular contact with the PD participant. PD participants were assigned a diagnosis of normal cognition, mild cognitive impairment, or dementia based on expert consensus.nnnRESULTSnPDAQ-15 scores correlated strongly with global cognition (Dementia Rating Scale-2, r = 0.71, p < 0.001) and a performance-based functional measure (Direct Assessment of Functional Status, r = 0.83; p < 0.001). PDAQ-15 scores accurately discriminated between non-demented PD participants (normal cognition/mild cognitive impairment) and PD with dementia (ROC curve area = 0.91), participants with and without any cognitive impairment (normal cognition versus mild cognitive impairment/dementia, ROC curve area = 0.85) and between participants with mild cognitive impairment and dementia (ROC curve area = 0.84).nnnCONCLUSIONSnThe PDAQ-15 shows good discriminant validity across cognitive stages, correlates highly with global cognitive performance, and appears suitable to assess daily cognitive functioning in PD.

Differential Effects of Goal Cues on Everyday Action Errors in Alzheimer's Disease Versus Parkinson's Disease Dementia

OBJECTIVEnPrior research has shown that individuals with Parkinsons disease dementia (PDD) show a different pattern of error types on everyday tasks compared with individuals with Alzheimers disease (AD). This study evaluated whether these groups would respond differently to cues designed to remind participants of task goals and improve performance of everyday tasks (i.e., goal cues).nnnMETHODnParticipants with PDD (n = 20) and AD (n = 20), and a comparison group of individuals with Parkinsons disease and no dementia (n = 20), were administered performance-based tasks of everyday functioning that allowed for the quantification of errors before and after the presentation of goal cues.nnnRESULTSnAD participants showed a significantly greater response to the goal cues as compared with individuals with PDD. The goal cues facilitated the completion of task goals but did not promote error correction (i.e., the undoing of errors that had been made earlier during the task).nnnCONCLUSIONSnNot all dementia patients respond similarly to cues designed to improve everyday functioning. Understanding patients specific form of everyday action impairment is crucial for developing individualized interventions that target specific functional deficits.