Gait and risk of falls associated with frontal cognitive functions at different stages of Alzheimer's disease

ABSTRACT

The decline in frontal cognitive functions contributes to alterations of gait and increases the risk of falls in patients with dementia, a category which included Alzheimer's disease (AD). The objective of the present study was to compare the gait parameters and the risk of falls among patients at different stages of AD, and to relate these variables with cognitive functions. This is a cross-sectional study with 23 patients with mild and moderate AD. The Clinical Dementia Rating was used to classify the dementia severity. The kinematic parameters of gait (cadence, stride length, and stride speed) were analyzed under two conditions: (a) single task (free gait) and (b) dual task (walking and counting down). The risk of falls was evaluated using the Timed Up-and-Go test. The frontal cognitive functions were evaluated using the Frontal Assessment Battery (FAB), the Clock Drawing Test (CDT) and the Symbol Search Subtest. The patients who were at the moderate stage suffered reduced performance in their stride length and stride speed in the single task and had made more counting errors in the dual task and still had a higher fall risk. Both the mild and the moderate patients exhibited significant decreases in stride length, stride speed and cadence in the dual task. Was detected a significant correlation between CDT, FAB, and stride speed in the dual task condition. We also found a significant correlation between subtest Similarities, FAB and cadence in the dual task condition. The dual task produced changes in the kinematic parameters of gait for the mild and moderate AD patients and the gait alterations are related to frontal cognitive functions, particularly executive functions.     

Intrusive and non‐intrusive memories in a non‐clinical sample: The effects of mood and affect on imagery vividness

We studied the number, valence, and vividness of intrusive and non‐intrusive memories in two groups (N = 20) of pre‐screened non‐depressed mood and depressed mood undergraduate participants. They were asked to generate as many intrusive memories (IMs) as possible from the prior 2 weeks, together with pleasant and unpleasant non‐intrusive memories from the same period. They subsequently formed images of these memories and rated them on measures of vividness, valence, arousal, and overall affect, while having their heart rate, skin conductance, and electromyogram monitored. IMs were common, with participants generating a mean of 1.15 pleasant IMs and 1.60 unpleasant IMs, and there was some evidence that they were mood‐congruent. IMs were more vivid than non‐intrusive memories, a difference not due to either valence or arousal. We conclude that IMs are a general feature of human memory rather than just a symptom of certain clinical disorders.     

Pilot study testing the effects of a multicomponent intervention for increasing moderate-intensity physical exercise

Physical inactivity has been associated with several health problems, including diabetes, obesity, and heart disease. Although many of these health problems are preventable through regular exercise, a small percentage of the adult population engages in the recommended levels. Reinforcement-based interventions have been implemented successfully to promote physical activity, but studies targeting moderate or vigorous physical exercise using behavior-analytic interventions are scarce. The purpose of the current study was to investigate the feasibility of a multicomponent intervention that provided monetary incentives for increasing running, jogging, or brisk walking distance for five adults. The intervention lasted 6 weeks and comprised weekly goal setting, feedback, public posting, and group contingencies. The results of the study suggest that the intervention may be feasible and effective at increasing moderate physical activity to levels recommended by the federal guidelines, but further research is warranted.     

Moral violations reduce oral consumption

Consumers frequently encounter moral violations in everyday life. They watch movies and television shows about crime and deception, hear news reports of corporate fraud and tax evasion, and hear gossip about cheaters and thieves. How does exposure to moral violations influence consumption? Because moral violations arouse disgust and because disgust is an evolutionarily important signal of contamination that should provoke a multi-modal response, we hypothesize that moral violations affect a key behavioral response to disgust: reduced oral consumption. In three experiments, compared with those in control conditions, people drank less water and chocolate milk while (a) watching a film portraying the moral violations of incest, (b) writing about moral violations of cheating or theft, and (c) listening to a report about fraud and manipulation. These findings imply that “moral disgust” influences consumption in ways similar to core disgust, and thus provide evidence for the associations between moral violations, emotions, and consumer behavior.     

Eye closure reduces the cross-modal memory impairment caused by auditory distraction

Eyewitnesses instructed to close their eyes during retrieval recall more correct and fewer incorrect visual and auditory details. This study tested whether eye closure causes these effects through a reduction in environmental distraction. Sixty participants watched a staged event before verbally answering questions about it in the presence of auditory distraction or in a quiet control condition. Participants were instructed to close or not close their eyes during recall. Auditory distraction did not affect correct recall, but it increased erroneous recall of visual and auditory details. Instructed eye closure reduced this effect equally for both modalities. The findings support the view that eye closure removes the general resource load of monitoring the environment rather than reducing competition for modality-specific resources.     

The contribution of phonological short-term memory to artificial grammar learning

Three experiments investigated the contribution of phonological short-term memory (STM) to grammar learning by manipulating rehearsal during study of an auditory artificial grammar made up from a vocabulary of spoken Mandarin syllables. Experiment 1 showed that concurrent, irrelevant articulation impaired grammar learning compared with a nonverbal control task. Experiment 2 replicated and extended this finding, showing that repeating the grammatical strings at study improved grammar learning compared with suppressing rehearsal or remaining silent during learning. Experiment 3 found no effects of rehearsal on grammar learning once participants had learned the component syllables. The findings suggest that phonological STM aids artificial grammar learning via effects on vocabulary learning.     

Treatment Response in CP/ADHD Children with Callous/Unemotional Traits

The current study examines the role of callous/unemotional (CU) traits in response to treatment among children with conduct problems (CP) and attention-deficit/hyperactivity disorder (ADHD). Fifty-four children with CP/ADHD and 16 controls (age = 9.48, SD = 1.58) took part in a summer treatment and research program. Simple correlations showed that CU and CP were associated with a number of treatment outcome measures. When examined together in regression analyses, CU and CP were uniquely associated with three treatment outcomes each (CU—improvement in social skills and problem solving, negative behaviors in time-out; CP—time-outs per day, peer ratings, peer dislike). The implications for these findings with regard to treatment response in children with CP/ADHD with and without CU traits are explored.     

Dynamic visual noise reduces confidence in short-term memory for visual information

Previous research has shown effects of the visual interference technique, dynamic visual noise (DVN), on visual imagery, but not on visual short-term memory, unless retention of precise visual detail is required. This study tested the prediction that DVN does also affect retention of gross visual information, specifically by reducing confidence. Participants performed a matrix pattern memory task with three retention interval interference conditions (DVN, static visual noise and no interference control) that varied from trial to trial. At recall, participants indicated whether or not they were sure of their responses. As in previous research, DVN did not impair recall accuracy or latency on the task, but it did reduce recall confidence relative to static visual noise and no interference. We conclude that DVN does distort visual representations in short-term memory, but standard coarse-grained recall measures are insensitive to these distortions.     

Negative Intrusive Thoughts and dissociation as Risk Factors for Self‐Harm

Relationships between self‐harm and vulnerability factors were studied in a general population of 432 participants, of whom 30% reported some experience of self‐harm. This group scored higher on dissociation and childhood trauma, had lower self‐worth, and reported more negative intrusive thoughts. Among the non‐harming group, 10% scored similarly to the self‐harmers on the dissociation and self‐worth scales, and engaged in potentially maladaptive behaviors that are not defined as indicating clinical self‐harm, but experienced fewer negative intrusive thoughts. This group may be at risk of future self‐harm if they begin to experience negative intrusive thoughts. If negative intrusive thoughts are playing a causal role, then therapeutic approaches tackling them may help those who are currently self‐harming.