Tool use in left brain damage and Alzheimer's disease: What about function and manipulation knowledge?

Tool use disorders are usually associated with difficulties in retrieving function and manipulation knowledge. Here, we investigate tool use (Real Tool Use, RTU), function (Functional Association, FA) and manipulation knowledge (Gesture Recognition, GR) in 17 left‐brain‐damaged (LBD) patients and 14 AD patients (Alzheimer disease). LBD group exhibited predicted deficit on RTU but not on FA and GR while AD patients showed deficits on GR and FA with preserved tool use skills. These findings question the role played by function and manipulation knowledge in actual tool use.     

The Portuguese version of Addenbrooke’s Cognitive Examination–Revised (ACE-R) in the diagnosis of subcortical vascular dementia and Alzheimer’s disease

The aim of this study was to investigate the accuracy of the Portuguese version of Addenbrooke’s Cognitive Examination–Revised (ACE-R) in detecting and differentiating early stage subcortical vascular dementia (SVD) from early stage Alzheimer’s disease (AD). Ninety-two subjects (18 SVD patients, 36 AD patients, and 38 healthy controls) were assessed using the ACE-R. Between-group’s differences were evaluated using the Quade’s rank analysis of covariance. The diagnostic accuracy and discriminatory ability of the ACE-R were examined via receiver operating characteristic (ROC) analysis. The ACE-R was able to successfully discriminate between patients and healthy subjects. The mean ACE-R total scores differed between SVD and AD patients; there were also significant differences in attention and orientation and in memory measures between the groups. An optimal cut-off of 72/73 was found for the detection of AD (sensitivity: 97%; specificity: 92%) and SVD (sensitivity: 100%; specificity: 92%).     

Effort to reduce postural sway affects both cognitive and motor performances in individuals with Parkinson’s disease

ObjectivesTo assess the effects of voluntarily reducing postural sway on postural control and to determine the attention level needed to do so in healthy adults (n = 16, 65.9 ± 9.7) and persons with PD (n = 25, 65.8 ± 9.5 years). Tasks: quiet and still standing conditions with and without a category task. Cognitive performance, center of pressure (CoP) displacement variability (RMSCoP) and velocity (VCoP) were assessed in the anterior-posterior (AP) and medial-lateral (ML) directions.Controls showed larger RMSCoP (AP) and VCoP (AP and ML) during still versus quiet standing (p < 0.01), while the PD group demonstrated no changes. In the PD group, RMSCoP and VCoP (ML) increased in still standing when performed with the cognitive task (p < 0.05). In both groups, cognitive responses decreased in still standing (p < 0.05).In PD, attempting to reduce postural sway did not affect postural control under single task conditions, however ML CoP variability and velocity did increase as a dual task. In older adults, increased displacement and velocity in both AP and ML directions was observed during single, but not dual task conditions. Therefore standing still might not be an adequate postural strategy as it increases the attentional demand and affects motor performance, putting persons with PD at greater risk for falls.