The role of awareness in the control of frontalis muscle activity

Can doubt attenuate access to internal states? Implications for obsessive-compulsive disorder

BACKGROUND AND OBJECTIVES

We have previously reported that obsessive-compulsive individuals perform more poorly on tasks that require accurate perception of internal states. As these individuals are also characterized by elevated levels of doubt regarding internal states, the causal relationship between doubt and accurate perception remained unclear. The presented study examines whether undermining participants' confidence in their ability to accurately produce a specific internal state would affect their performance on a task that requires accurate perception of this state.

METHODS

Participants were trained to produce specific levels of forearm muscle tension and then required to produce various tension levels in four experimental phases. The first three alternated in terms of whether the participants viewed a biofeedback monitor while the fourth offered participants several times the choice to view the monitor. Prior to the task, half of the participants received instructions that undermined their confidence in their ability to accurately assess their own muscle tension. We measured participants' accuracy in producing the required muscle tension levels and the number of times they requested to view the monitor in the final phase.

RESULTS

Undermined confidence participants were less accurate in producing the required muscle tension levels in the absence of biofeedback, and were also more likely to request the monitor in the final phase.

CONCLUSIONS

Doubt can affect performance on tasks that require perceiving and experiencing internal states. This finding supports the possibility that access to internal states in OCD is attenuated due to elevated levels of doubt regarding these states.

Obsessive-compulsive tendencies and undermined confidence are related to reliance on proxies for internal states in a false feedback paradigm

BACKGROUND AND OBJECTIVES

We have previously hypothesized that obsessive-compulsive (OC) tendencies are associated with a general lack of subjective conviction regarding internal states, which leads to compensatory seeking of and reliance on more discernible substitutes (proxies) for these states (Lazarov, A., Dar, R., Oded, Y., & Liberman, N. (2010). Behaviour Research and Therapy, 48, 516-523). This article presents two studies designed to provide further support to this hypothesis by using false biofeedback as a proxy for internal states.

METHODS

In Study 1 we presented high and low OC participants with pre-programmed false feedback showing either increasing or decreasing levels of muscle tension. In Study 2 we presented similar false feedback on level of relaxation to non-selected participants, half of which received instructions that undermined their confidence in their ability to assess their own level of relaxation.

RESULTS

In Study 1, high OC participants were more affected by false biofeedback when judging their own level of muscle tension than were low OC participants. In Study 2, undermined confidence participants were more affected by false biofeedback when judging their own level of relaxation as compared to control participants.

LIMITATIONS

Our findings are based on a non-clinical, highly functioning, largely female student sample and their generalization to OCD requires replication with a sample of OCD patients.

CONCLUSIONS

These results provide converging evidence for our hypothesis by replicating and extending our previous findings. We discuss the implication of our hypothesis for the understanding and treatment of OCD and outline directions for future research.

Interoception

During the last two decades, research on interoception has experienced a surprising renaissance. New experimental approaches and methods have revealed much about the processing of afferent signals from the inner organs of the body, and have allowed more accurate descriptions of these processes, as well as a more accurate determination of their functional significance in the experience and behavior of humans. Besides neuromuscular, respiratory, and gastrointestinal interoceptive processes, the cardiovascular afferent influences are now known to be very important. Invariably, the central questions concern sensitivity to signals from the body, factors which may influence judgement of perception, and the degree to which conventional hypotheses regarding the interoceptive capabilities of humans may require revision. Findings from general psychological and clinical studies have shown that humans may attain remarkable levels of interoceptive performance. On the other hand, they also show how deep the chasm is between visceral processes and perception, and between that which is perceived and the reports thereof. Only interdisciplinary approaches to these complex processes promise success.

The role of EMG awareness in EMG biofeedback learning

Underlying most research on biofeedback learning is a theoretical model of the processes involved. The current study tested a prediction from the Awareness Model: High initial EMG awareness should facilitate response control during EMG biofeedback training. Seventy-two undergraduates were assessed for forehead EMG awareness by asking them to produce target responses from 1.0 to 5.0 microV every 15 s for 16 trials. Based on this assessment, two groups (high and low awareness) were trained for 64 trials to produce these target levels with either EMG biofeedback, practice (no feedback), or noncontingent EMG feedback. A transfer task was identical to the initial assessment. During training, the biofeedback group deviated less from target than the practice and noncontingent groups. The biofeedback group was the only group to improve from initial EMG awareness activity. During transfer, only the low awareness biofeedback group remained below initial EMG awareness level. These findings can be interpreted in terms of the Two-Process Model.

A new procedure for assessment of proprioception

A new method for the assessment of proprioception was developed and tested with 40 healthy subjects on two facial muscles (i.e., masseter and zygomatic muscles). The experiment was repeated after 3 1/2 months. In our study, proprioception was studied with respect to sensations arising from the muscle spindles and tendon organs. Therefore, myesthesia was investigated, which was assessed by the correspondence between a voluntary muscle contraction and its immediate replication. Good perception was defined by a small integral of differences, standardized by duration and intensity of the contraction, and its replication. Results show that this measure is independent of the characteristics of muscle activation. In concordance with our hypothesis, myesthesia was superior in a muscle richly supplied with muscle spindles and afferent fibers (i.e., masseter muscle), to that for a muscle less prepared for afferent information processing (i.e., zygomatus major).

Psychophysics of muscle tension in psychiatric inpatients

Twelve psychiatric inpatients and 16 control subjects each took part in a psychophysics experiment in which the method of production was used to study the perception of tension in the frontalis and forearm extensor muscles. Subjects tensed each muscle between 0% and 50% maximum effort, with 25% effort repeated every third trial, and used as a reference stimulus. Patients showed significantly lower correlations between frontalis EMG and percent effort than the control subjects, but no between-groups differences were found for forearm. Correlations were higher for differences between successive trials than for absolute values because of apparent baseline shifts in perception and/or production of muscle tension. The performance among the patients was not correlated with severity of psychiatric symptoms, antipsychotic medication, abnormal movements, or parkinsonian symptoms, although the n was small. Analysis of the regression of EMG on percent effort revealed approximately equal descriptive strength for three functions: a linear relationship, Stevens' power function, and Fechner's law. The implications of these findings for self-regulation therapies are discussed.

The effects of electromyographic feedback training on suppression of the oral-lingual movements associated with tardive dyskinesia

The efficacy of electromyographic feedback training in reducing the magnitude and frequency of the oral-lingual movements associated with tardive dyskinesia (TD) was investigated in a groups design. Twenty adult male inpatients diagnosed as having TD using the Abnormal Involuntary Movements Scale (AIMS) were randomly assigned to one of two treatment conditions. Following identification, all participants were initially reduced to the lowest effective dosage of neuroleptics, and then discontinued from anticholinergics. Following one month on this regimen, they were given a course of feedback training consisting of ten 14-minute sessions. Group one participants were provided with a tone contingent upon oral-lingual movements above a yoked threshold. Group two participants were given noncontingent feedback tones generated randomly. Weekly AIMS were administered as well as an initial baseline during each session to determine current level of oral-lingual activity. An analysis of session effects indicated significantly more suppression of oral-lingual activity in the contingent group versus the noncontingent feedback group. Jaw and forehead activity also measured showed reductions of similar magnitudes for both groups.