Association between attentional bias to experimentally induced pain and to pain-related words in healthy individuals: the moderating role of interpretation bias

A randomized controlled trial modifying insomnia-consistent interpretation bias in students

This study aimed to determine the causal role of insomnia-consistent interpretation bias within the cognitive model of insomnia, by modifying this bias in students experiencing subclinical levels of insomnia and assessing subsequent effects on sleep parameters. A sample of 128 students underwent randomization to receive either a single session of online Cognitive Bias Modification-Interpretation (CBM-I) or a sham training. Participants then tracked their pre-sleep worry and sleep parameters for seven consecutive days. Interpretation bias was assessed using an encoding-recognition task specifically designed for insomnia-related interpretation bias. The CBM-I manipulation utilized ambiguous scenarios to redirect participants away from making insomnia-related interpretations. Results revealed that CBM-I effectively decreased insomnia-consistent interpretation bias compared to the sham treatment, with interpretation bias being absent post-training in the CBM-I group. This reduction did not lead to improvements in pre-sleep worry or any sleep parameters. This study has been the first to investigate the causal role of interpretation bias on symptoms of insomnia. Although results indicated this bias to be modifiable, its causality within the cognitive model proves to be more complicated. Future research focusing on optimization of cognitive bias modifications could shed more light on the effects of biased cognitions on insomnia symptoms.

The Interrelationships Between Cognitive Biases for Pain: An Experimental Study

Contemporary pain models highlight cognitive-processing biases (ie, attention bias [AB], interpretation bias [IB], and memory bias [MB]) as key processes that contribute to poor pain outcomes. However, existing research has yielded inconsistent findings regarding the presence and impact of these biases on pain outcomes. Recognizing the need to explore these biases simultaneously, contemporary pain models suggest that cognitive biases (CBs) are interrelated, and may have a combined impact upon pain problems. The current study aims to investigate the interrelationships between CBs using the PainAIM paradigm, a novel approach enabling simultaneous evaluation of pain-related AB, IB, and MB using cues signaling actual pain rather than symbolic information. We hypothesized the presence and positive associations of biases for pain-related cues and the predictive value of combined AB and IB for poor pain outcomes. Eighty-four healthy participants completed the PainAIM paradigm, followed by a cold pressor task probing pain experience and pain-related task interference. The results indicated an inverse relationship between AB and IB for ambiguous pain cues. In addition, there was a positive association between participants' AB for ambiguous pain and their MB for the same cues. Contrary to our hypotheses, CB indices did not predict experimental pain outcomes. These findings provide support for the interrelationships between pain-related CBs. However, future research on the temporal order of CBs and their combined impact on pain outcomes is needed. By overcoming the limitations associated with traditional paradigms, the PainAIM paradigm offers a promising research tool for the further study of combined CBs in the context of pain. PERSPECTIVE: The current study provides insight into the associations between pain-related CBs (AB, IB, and MB) using ecologically valid (ambiguous) pain cues. The results indicated an inverse association between pain-related AB and IB, while a positive association was found between AB and MB. CBs did however not predict experimental pain outcomes.

Associations Between Temporomandibular Disorders and Brain Imaging-Derived Phenotypes

OBJECTIVE

Temporomandibular disorders (TMD) affect the temporomandibular joint and associated structures. Despite its prevalence and impact on quality of life, the underlying mechanisms of TMD remain unclear. Magnetic resonance imaging studies suggest brain abnormalities in patients with TMD. However, these lines of evidence are essentially observational and cannot infer a causal relationship. This study employs Mendelian randomisation (MR) to probe causal relationships between TMD and brain changes.

METHODS

Genome-wide association study (GWAS) summary statistics for TMD were collected, along with brain imaging-derived phenotypes (IDPs). Instrumental variables were selected from the GWAS summary statistics and used in bidirectional 2-sample MR analyses. The inverse-variance weighted analysis was chosen as the primary method. In addition, false discovery rate (FDR) correction of P value was used.

RESULTS

Eleven IDPs related to brain imaging alterations showed significant causal associations with TMD (P-FDR < .05), validated through sensitivity analysis. In forward MR, the mean thickness of left caudal middle frontal gyrus (OR, 0.76; 95% CI, 0.67-0.87; P-FDR = 1.15  ×  10-2) and the volume of right superior frontal gyrus (OR, 1.24; 95% CI, 1.10-1.39; P-FDR = 2.26  ×  10-2) exerted significant causal effects on TMD. In the reverse MR analysis, TMD exerted a significant causal effect on 9 IDPs, including the mean thickness of the left medial orbitofrontal cortex (β = -0.10; 95% CI, -0.13 to -0.08; P-FDR = 2.06 × 10-11), the volume of the left magnocellular nucleus (β = -0.15; 95% CI, -0.22 to -0.09; P-FDR = 3.26 × 10-4), the mean intensity of the right inferior-lateral ventricle (β = -0.09; 95% CI, -0.14 to -0.04; P-FDR = 2.23 × 10-2), the volume of grey matter in the anterior division of the left superior temporal gyrus (β = 0.09; 95% CI,  0.04-0.14; P-FDR = 1.69 × 10-2), and so forth.

CONCLUSIONS

This study provides genetic evidence supporting the bidirectional causal associations between TMD and brain IDPs, shedding light on potential neurobiological mechanisms underlying TMD development and its relationship with brain structure.

Acute Itch Induces Attentional Avoidance of Itch-related Information

Attention is known to modulate itch intensity. In contrast, the reverse relationship, i.e. the degree to which the presence of an acute itch affects attention, is currently not well understood. The aims of this study were to investigate whether acute itch induces an attentional bias towards or away from visual itch-related stimuli, and if so, whether it occurs in the early or later stages of processing. A volunteer sample of 60 healthy individuals were subjected to a skin prick (either histamine or placebo), followed by completion of a spatial cueing paradigm using itch-related and neutral words as cues, in order to obtain reaction time estimates of attentional bias. The results suggest that experience of acute itch induces attentional avoidance of visual itch threats. This attentional avoidance occurs at a later processing stage in the form of facilitated disengagement of attention from itch and/or delayed disengagement from neutral information.