Q-Coh: A tool to screen the methodological quality of cohort studies in systematic reviews and meta-analyses

The evaluation of the methodological quality of primary studies in a systematic review is a key process to enhance the likelihood of achieving valid results. When considering non-randomized designs as cohort studies, this process becomes even more critical, since these designs are more susceptible to bias than randomized controlled trials are. Taking this into account, a tool, named Q-Coh, was designed with the aim to screen the methodological quality of the primary studies with a cohort design priming specificity over sensitivity in a reasonable application time. After applying it to 21 prospective cohort studies by three raters, all domains had a moderate to good agreement, with all except one of them having statistically significant kappa values. Despite there is no gold standard for the methodological quality, arguments supporting its validity are given. Future research should assess the psychometric properties of Q-Coh in the context of real meta-analyses, evaluate the influence of the raters’ substantive and methodological expertise on these properties, and explore different ways of including the domains-based ratings of the quality provided by Q-Coh into meta-analyses.     

Rats learn to eat more to avoid hunger

Several recent experiments have provided evidence that the ingestion of a distinctive food by rats can be a learnt instrumental act as well as an associatively conditioned reaction. In the previous work, maintenance food was withheld for shorter and longer durations on different days following access to the training food. Extra eating before the longer fast was interpreted as avoidance of hunger. This interpretation was based on the evidence showing that extra eating as a result of classical conditioning comes from pairing food stimuli with the presence of little or no hunger because of repletion with energy nutrients. The theory that the extra eating arose from a response-depletion contingency was tested in the present experiment by training rats on only a long fast or only a short fast. Greater increase in intake was seen before the longer fast. The results also replicated previously seen cycles of increase, decrease, and renewed increase in putative deficit-avoidant eating over about three trials, indicating that the extra eating reduces the response-reinforcing hunger and that the consequent part-extinction restores reinforcement. The shape of the learning curve was consistent with these cycles occurring from the start of training, further supporting the view that the increase in food intake before a long delay in refeeding is hunger-reinforced instrumental behaviour.     

Speech in spinocerebellar ataxia

Spinocerebellar ataxias (SCAs) are a heterogeneous group of autosomal dominant cerebellar ataxias clinically characterized by progressive ataxia, dysarthria and a range of other concomitant neurological symptoms. Only a few studies include detailed characterization of speech symptoms in SCA. Speech symptoms in SCA resemble ataxic dysarthria but symptoms related to phonation may be more prominent. One study to date has shown an association between differences in speech and voice symptoms related to genotype. More studies of speech and voice phenotypes are motivated, to possibly aid in clinical diagnosis. In addition, instrumental speech analysis has been demonstrated to be a reliable measure that may be used to monitor disease progression or therapy outcomes in possible future pharmacological treatments.     

Psychopathy and aggression: Examining the role of psychopathy factors in predicting laboratory aggression under hostile and instrumental conditions

Psychopathy is a problematic configuration of traits and behaviors that is consistently correlated with aggressive, criminal behavior. Studies have suggested that psychopathy is composed of related but distinct factors that manifest divergent relations with a host of constructs including aggression. In the current study, we used a sample of 126 men to examine whether these psychopathy factors are differentially related to aggression manifested in two conditions (instrumental and hostile/reactive aggression) of a laboratory aggression paradigm. Traits related to an antagonistic interpersonal style and emotional detachment (i.e., Factor 1) were related to aggression in both conditions whereas traits related to negative emotionality, impulsivity, and an antagonistic style (i.e., Factor 2) were related to aggression only in the hostile/reactive condition. Potential explanations for these findings are put forth.     

Associations in human instrumental conditioning

Four experiments were conducted to study the contents of human instrumental conditioning. Experiment 1 found positive transfer between a discriminative stimulus (S^D) and an instrumental response (R) that shared the outcome (O) with the response that was originally trained with the S^D, showing the formation of an S^D → O association. Experiment 2 found that post-acquisition devaluation of an outcome selectively reduced the response trained with that outcome, showing the formation of a R → O association. In Experiment 3, changing the outcome did not prevent participants from giving the response learned with each S^D, even though none of the responses was appropriate for the new outcome, showing evidence of the formation of S^D → R associations in instrumental learning. The three binary associations were shown within the same basic experimental situation. Finally, Experiment 4 found evidence of the formation of the higher order association S^D(R → O) in human instrumental conditioning.     

People with intellectual disability who are ageing: Perceived needs assessment

Background/Objective: Ageing and progressive increase in life expectancy in people with intellectual disability present significant challenges. The present study is to examine the needs that arise in the aging process of this population. To detect these needs is fundamental to ensure personal wellbeing; almost no psychometrically sound instruments have been developed. Method: A structured interview was developed and evaluated by a panel of 20 experts to obtain evidence of content validity. The interview was then applied to 1,173 people with intellectual disability. The ages ranged from 35 to 80 (M = 52.27; SD = 7.5). Results: The interview consisted of 93 items evaluating four areas: perceived needs, personal problems, future perspectives, and solutions required. The results demonstrated the proximity and relationship of the various needs evaluated. In addition it was observed that those with intellectual disability who were older, male and users of residential services tended to indicate more needs, problems, and required more solutions. Conclusions: The instrument has adequate evidence of validity, allowing the evaluation of specific needs of people with intellectual disability. The results advocate the design of transversal intervention policies in order to effectively meet the needs and requirements of this population.     

Instrumental learning in hyperdopaminergic mice

In two experiments we investigated the effects of elevated dopaminergic tone on instrumental learning and performance using dopamine transporter knockdown (DAT KD) mice. In Experiment 1, we showed that both DAT KD mice and wild-type controls were similarly sensitive to outcome devaluation induced by sensory specific satiety, indicating normal action-outcome learning in both groups. In Experiment 2, we used a Pavlovian-to-instrumental transfer procedure to assess the potentiation of instrumental responding by Pavlovian conditional stimuli (CS). Although during the Pavlovian training phase the DAT KD mice entered the food magazine more frequently in the absence of the CS, when tested later both groups showed outcome-selective PIT. These results suggest that the elevated dopaminergic tone reduced the selectivity of stimulus control over conditioned behavior, but did not affect instrumental learning.