The Efficacy of Cognitive Intervention in Mild Cognitive Impairment (MCI): a Meta-Analysis of Outcomes on Neuropsychological Measures

Cognitive training in MCI may stimulate pre-existing neural reserves or recruit neural circuitry as “compensatory scaffolding” prompting neuroplastic reorganization to meet task demands (Reuter-Lorenz & Park, 2014). However, existing systematic reviews and meta-analytic studies exploring the benefits of cognitive interventions in MCI have been mixed. An updated examination regarding the efficacy of cognitive intervention in MCI is needed given improvements in adherence to MCI diagnostic criteria in subject selection, better defined interventions and strategies applied, increased use of neuropsychological measures pre- and post-intervention, as well as identification of moderator variables which may influence treatment. As such, this meta-analytic review was conducted to examine the efficacy of cognitive intervention in individuals diagnosed with mild cognitive impairment (MCI) versus MCI controls based on performance of neuropsychological outcome measures in randomized controlled trials (RCT). RCT studies published from January 1995 to June 2017 were obtained through source databases of MEDLINE-R, PubMed, Healthstar, Global Health, PSYCH-INFO, and Health and Psychological Instruments using search parameters for MCI diagnostic category (mild cognitive impairment, MCI, pre-Alzheimer’s disease, early cognitive decline, early onset Alzheimer’s disease, and preclinical Alzheimer’s disease) and the intervention or training conducted (intervention, training, stimulation, rehabilitation, or treatment). Other inclusion and exclusion criteria included subject selection based on established MCI criteria, RCT design in an outpatient setting, MCI controls (active or passive), and outcomes based on objective neuropsychological measures. From the 1199 abstracts identified, 26 articles met inclusion criteria for the meta-analyses completed across eleven (11) countries; 92.31% of which have been published within the past 7 years. A series of meta-analyses were performed to examine the effects of cognitive intervention by cognitive domain, type of training, and intervention content (cognitive domain targeted). We found significant, moderate effects for multicomponent training (Hedges’ g observed?=?0.398; CI [0.164, 0.631]; Z?=?3.337; p?=?0.001; Q?=?55.511; df?=?15; p?=?0.000; I ² ?=?72.978%; τ ² ?=?0.146) as well as multidomain-focused strategies (Hedges’ g?=?0.230; 95% CI [0.108, 0.352]; Z?=?3.692; p??< 0.001; Q?=?12.713; df?=?12; p?=?0.390; I ² ?=?5.612; τ ² ?=?0.003). The effects for other interventions explored by cognitive domain, training type, or intervention content were indeterminate due to concerns for heterogeneity, bias, and small cell sizes. In addition, subgroup and meta-regression analyses were conducted with the moderators of MCI category, mode of intervention, training type, intervention content, program duration (total hours), type of control group (active or passive), post-intervention follow-up assessment period, and control for repeat administration. We found significant overall effects for intervention content with memory focused interventions appearing to be more effective than multidomain approaches. There was no evidence of an influence on outcomes for the other covariates examined. Overall, these findings suggest individuals with MCI who received multicomponent training or interventions targeting multiple domains (including lifestyle changes) were apt to display an improvement on outcome measures of cognition post-intervention. As such, multicomponent and multidomain forms of intervention may prompt recruitment of alternate neural processes as well as support primary networks to meet task demands simultaneously. In addition, interventions with memory and multidomain forms of content appear to be particularly helpful, with memory-based approaches possibly being more effective than multidomain methods. Other factors, such as program duration, appear to have less of an influence on intervention outcomes. Given this, although the creation of new primary network paths appears strained in MCI, interventions with memory-based or multidomain forms of content may facilitate partial activation of compensatory scaffolding and neuroplastic reorganization. The positive benefit of memory-based strategies may also reflect transfer effects indicative of compensatory network activation and the multiple-pathways involved in memory processes. Limitations of this review are similar to other meta-analysis in MCI, including a modest number studies, small sample sizes, multiple forms of interventions and types of training applied (some overlapping), and, while greatly improved in our view, a large diversity of instruments used to measure outcome. This is apt to have contributed to the presence of heterogeneity and publication bias precluding a more definitive determination of the outcomes observed.     

Over-specified referring expressions impair comprehension: an ERP study

Speakers often include extra information when producing referring expressions, which is inconsistent with the Maxim of Quantity (Grice, 1975). In this study, we investigated how comprehension is affected by unnecessary information. The literature is mixed: some studies have found that extra information facilitates comprehension and others reported impairments. We used an attentional-cueing paradigm to assess how quickly participants could orient attention to an object upon hearing a referring expression, such as the red square. If there are two squares differing in color, then the modifier is required. However, if there is only one (red) square, then the modifier is unnecessary. We also recorded event-related potentials (ERPs) in order to investigate online processing. Reaction times were significantly longer for referring expressions that contained extra information, and ERPs revealed a centroparietal negativity (N400) that emerged approximately 200–300 ms after modifier onset. We conclude that referring expressions with an unnecessary pre-nominal modifier impair comprehension performance.     

Effect of Transcranial Direct Current Stimulation Combined With Virtual Reality Training on Balance in Children With Cerebral Palsy: A Randomized,Controlled, Double-Blind,Clinical Trial

The authors' aim was to investigate the effects of continuous transcranial direct current stimulation (tDCS) combined with virtual reality training on static and functional balance in children with cerebral palsy (CP). Twenty children with CP (6 girls and 14 boys; M age = 7 years 6 months ± 2 years) were randomly allocated to two groups. The experimental group received active tDCS and the control group received sham stimulation during the 10 sessions of virtual reality mobility training protocols. The children were evaluated on 3 occasions (preintervention, postintervention, and 1-month follow-up). Static balance was evaluated using a force plate under 4 conditions: feet on force plate with (a) eyes open and (b) with eyes closed, and feet on foam mat with (c) eyes open and (d) with eyes closed. Functional balance was evaluated using the Pediatric Balance Scale and the Timed Up and Go Test. The analyses demonstrated statistically significant postintervention and follow-up effects favoring the experimental group over the control group with regard to the Pediatric Balance Scale, Timed Up and Go Test, and area of oscillation of the center of pressure when standing on the force plate with eyes open. The present findings suggest that tDCS can potentiate the effects of virtual reality training on static and functional balance among children with CP.     

Electromechanical delay in ballistic movement of superior limb: comparison between karate athletes and nonathletes

The aim of the study was to analyze electromechanical delay in a ballistic movement of the superior limb. 10 male karate athletes and 9 nonathletes (without karate experience) performed a motor skill as fast and powerfully as possible, with impact on a makiwara (karate training instrument). For each participant, 10 choku-zuki performances were analyzed. Kinematics and surface electromyographic (EMG) activity of the anterior and posterior portions of deltoid, pectoralis major, latissimus dorsi, triceps brachii, and biceps brachii were recorded. Athletes had significantly shorter delay in arm flexion agonist muscles and significantly higher delay in arm flexion antagonist muscles and in forearm extension agonists. Results suggest that enhanced performance in athletes was mainly due to motor learning.     

Are phonological influences on lexical (mis)selection the result of a monitoring bias?

A monitoring bias account is often used to explain speech error patterns that seem to be the result of an interactive language production system, like phonological influences on lexical selection errors. A biased monitor is suggested to detect and covertly correct certain errors more often than others. For instance, this account predicts that errors that are phonologically similar to intended words are harder to detect than those that are phonologically dissimilar. To test this, we tried to elicit phonological errors under the same conditions as those that show other kinds of lexical selection errors. In five experiments, we presented participants with high cloze probability sentence fragments followed by a picture that was semantically related, a homophone of a semantically related word, or phonologically related to the (implicit) last word of the sentence. All experiments elicited semantic completions or homophones of semantic completions, but none elicited phonological completions. This finding is hard to reconcile with a monitoring bias account and is better explained with an interactive production system. Additionally, this finding constrains the amount of bottom-up information flow in interactive models.     

Taking a new look at looking at nothing

A crucial question in cognitive science is how linguistic and visual information are integrated. Previous research has shown that eye movements to objects in the visual environment are locked to linguistic input. More surprisingly, listeners fixate on now-empty regions that had previously been occupied by relevant objects. This 'looking at nothing' phenomenon has been linked to the claim that the visual system constructs sparse representations of the external world and relies on saccades and fixations to extract information in a just-in-time manner. Our model provides a different explanation: based on recent work in visual cognition and memory, it assumes that the visual system creates and stores detailed internal memory representations, and that looking at nothing facilitates retrieval of those representations.     

Team climate,climate strength and team performance. A longitudinal study

We tested the hypothesis that the relationship between team climate and team performance is moderated by climate strength. The study sample was composed of 155 bank branches, and a two‐wave panel design was implemented. We measured four team climate facets (support, innovation, goal achievement and enabling formalization). We obtained two subjective indicators of team performance (ratings provided by team members and by team managers) and a financial indicator of team performance. Seven out of the 12 interaction effects tested were statistically significant and showed the expected sign. When financial team performance was the criterion, only the interaction term was significant. This suggests that only strong climates are related to financial team performance over time.     

ENSEMBLE RECORDINGS IN AWAKE RATS: ACHIEVING BEHAVIORAL REGULARITY DURING MULTIMODAL STIMULUS PROCESSING AND DISCRIMINATIVE LEARNING

To meet an increasing need to examine the neurophysiological underpinnings of behavior in rats, we developed a behavioral system for studying sensory processing, attention and discrimination learning in rats while recording firing patterns of neurons in one or more brain areas of interest. Because neuronal activity is sensitive to variations in behavior which may confound the identification of neural correlates, a specific aim of the study was to allow rats to sample sensory stimuli under conditions of strong behavioral regularity. Our behavioral system allows multimodal stimulus presentation and is coupled to modules for delivering reinforcement, simultaneous monitoring of behavior and recording of ensembles of well isolated single neurons. Using training protocols for simple and compound discrimination, we validated the behavioral system with a group of 4 rats. Within these tasks, a majority of medial prefrontal neurons showed significant firing‐rate changes correlated to one or more trial events that could not be explained from significant variation in head position. Thus, ensemble recordings can be combined with discriminative learning tasks under conditions of strong behavioral regularity.     

Priming Sentence Production in Adolescents and Adults with Attention-Deficit/Hyper-Activity Disorder

Theoretical accounts of attention-deficit/hyperactivity disorder (ADHD) posit a prominent role for problems in response inhibition (Nigg 2006). A key avenue for impulsivity in children with ADHD is inappropriate language expression. In this study, we sought to determine whether poor inhibitory control affects language production in adolescents and adults with ADHD. One hundred and ninety-five participants (13–35 years old; 65% male) were presented with two pictures and a verb, and their task was to form a sentence. If deficits in response inhibition affect language production, then participants with ADHD should be more likely than non-ADHD controls to begin speaking before having formulated a plan that will allow a grammatical continuation. The results showed that the ADHD-combined subtype, in particular, was more likely to produce an ungrammatical sequence. Effects were not moderated by age or gender. These data suggest that response suppression deficits in ADHD adversely affect the basic processes of sentence formation.     

Benefits of physical exercise on executive functions in older people with Parkinson’s disease

The benefits of physical exercise on cognitive functioning have been reported in the literature, but the potential benefits to slow the eventual decline in executive functioning (EF) caused by neurodegeneration from Parkinson’s Disease (PD) have rarely been studied. Thus the objective of this study was to analyze the effects of a multimodal physical exercise program on EF in older people with Parkinson’s disease. The EF of the older people was evaluated by neuropsychological testing, and for confounding variables such as attention, depressive symptoms and anxiety, before and after intervention. The 20 participants were assigned into Control (CG) and Trained (TG) Groups. The TG participated in generalized physical training for 6 months. The ANOVA showed a significant interaction (p < .05) that indicated a beneficial contribution of training on EF. No significant interactions were found in the results for confounding variables between groups and pre- and post-intervention, which supports the beneficial findings of physical exercise training on EF.