Calm with horses? A systematic review of animal-assisted interventions for improving social functioning in children with autism.

LAY ABSTRACT: Children with autism typically experience difficulties interacting socially with others when compared to their non-autistic peers. Establishing how effective interventions are for improving social functioning is important to help inform what should be offered to children with autism. This study reviewed how effective interventions that involved interaction with a live animal, known as animal-assisted interventions, are in improving social functioning in children with autism. A systematic search of the evidence on this topic found nine studies, which were explored for the effectiveness of animal-assisted interventions and the quality of methods used. Overall, these studies showed improvements in social functioning following equine-assisted or therapeutic horse-riding interventions, with initial evidence showing improvements are sustained in the short and medium term. However, several issues were identified, which limit the strength of any conclusions that can be drawn from this evidence. For example, in many studies people assessing the children were aware that they received the intervention or were in a control group. There was also not enough evidence available to draw conclusions on the effectiveness of other animal-assisted interventions. Future research should address the limitations that were common in the designs of these studies and investigate the potential benefit of other animal populations, such as dogs and cats.

Is Transcranial Direct Current Stimulation (tDCS) Effective for the Treatment of Pain in Fibromyalgia? A Systematic Review and Meta-Analysis.

BACKGROUND: Fibromyalgia is a debilitating condition characterized by chronic widespread pain. It is believed to be caused by dysfunction of the central nervous system (CNS) but current treatments are largely ineffective. Transcranial direct current stimulation (tDCS), a neuromodulation technique that targets the CNS, may offer a new line of treatment. OBJECTIVE: To systematically review the most up-to-date literature and perform a meta-analysis of the effects of tDCS on pain intensity in fibromyalgia. METHODS: The following databases were searched from inception: Medline (Ovid), PsychInfo, CINAHL, Cochrane Library, and Web of Science. Studies were eligible if they were randomized controlled trials, quasi-randomized trials, and nonrandomized. Crossover and parallel-group design studies were included. Risk of bias was assessed for all included studies. Meta-analysis was conducted on studies investigating pain intensity after tDCS in participants with fibromyalgia and analyzed using standardized mean difference and 95% confidence intervals. RESULTS: Fourteen clinical studies were included. Ten were controlled trials and 4 were within-subjects crossover studies. Meta-analysis of data from 8 controlled trials provides tentative evidence of pain reduction when active tDCS is delivered compared to sham. However, substantial statistical heterogeneity and high risk of bias of primary studies prevent more conclusive recommendations being made. CONCLUSIONS: tDCS is a safe intervention with the potential to lower pain intensity in fibromyalgia. However, there is a need for more empirical research of the neural target sites and optimum stimulation parameters to achieve the greatest effects before conducting further clinical studies. PERSPECTIVE: This systematic review and meta-analysis synthesizes current evidence for the clinical effectiveness of tDCS in the treatment of fibromyalgia pain. There is only tentative evidence of pain reduction when active tDCS is compared to sham. High heterogeneity and risk of bias across studies suggest a need for further empirical research.

The effect of interactive virtual reality on pain perception: a systematic review of clinical studies.

Purpose: The aim of this systematic review was to evaluate the effect of immersive and non-immersive interactive virtual reality on pain perception in patients with a clinical pain condition.Methods: The following databases were searched from inception: Medline (Ovid), PsychInfo, CINAHL, Cochrane library and Web of Science. Two reviewers screened reports and extracted the data. A third reviewer acted as an arbiter. Studies were eligible if they were randomized controlled trials, quasi-randomized trials, and uncontrolled trials. Crossover and parallel-group designs were included. Risk of bias was assessed for all included studies.Results: Thirteen clinical studies were included. The majority of studies investigated a sample of participants with chronic pain. Six were controlled trials and seven uncontrolled studies. Findings from controlled research suggest that interactive virtual reality may reduce pain associated with ankylosing spondylitis and post-mastectomy, but results are inconsistent for patients with neck pain. Findings from uncontrolled studies suggest that interactive virtual reality may reduce neuropathic limb pain, and phantom limb pain, but had no effect on nonspecific chronic back pain.Conclusions: There is a need for more rigorous randomized control trials in order to conclude on the effectiveness of the use of virtual reality for the management of pain.Implications for rehabilitationInteractive virtual reality has been increasingly used in the rehabilitation of painful conditions.Interactive virtual reality using exergames may promote distraction from painful exercises and reduce pain post-mastectomy and in patients with ankylosing spondylitis.Interactive virtual representation of limbs may reduce neuropathic and phantom limb pain.

Transcranial alternating current stimulation at 10 Hz modulates response bias in the Somatic Signal Detection Task.

Ongoing, pre-stimulus oscillatory activity in the 8-13 Hz alpha range has been shown to correlate with both true and false reports of peri-threshold somatosensory stimuli. However, to directly test the role of such oscillatory activity in behaviour, it is necessary to manipulate it. Transcranial alternating current stimulation (tACS) offers a method of directly manipulating oscillatory brain activity using a sinusoidal current passed to the scalp. We tested whether alpha tACS would change somatosensory sensitivity or response bias in a signal detection task in order to test whether alpha oscillations have a causal role in behaviour. Active 10 Hz tACS or sham stimulation was applied using electrodes placed bilaterally at positions CP3 and CP4 of the 10-20 electrode placement system. Participants performed the Somatic Signal Detection Task (SSDT), in which they must detect brief somatosensory targets delivered at their detection threshold. These targets are sometimes accompanied by a light flash, which could also occur alone. Active tACS did not modulate sensitivity to targets but did modulate response criterion. Specifically, we found that active stimulation generally increased touch reporting rates, but particularly increased responding on light trials. Stimulation did not interact with the presence of touch, and thus increased both hits and false alarms. TACS stimulation increased reports of touch in a manner consistent with our observational reports, changing response bias, and consistent with a role for alpha activity in somatosensory detection.

Managing limb pain using virtual reality: a systematic review of clinical and experimental studies.

Purpose: The aim of this systematic review was to assess the effect of virtual representation of body parts on pain perception in patients with pain and in pain-free participants exposed to experimentally induced pain.Methods: Databases searched: Medline, PsycInfo, CINAHL, and Web of Science. Studies investigating participants with clinical pain or those who were pain free and exposed to experimentally induced pain were analysed separately.Results: Eighteen clinical studies and seven experimental studies were included. Randomised controlled clinical trials showed no significant difference between intervention and control groups for pain intensity. Clinical studies with a single group pretest-posttest design showed a reduction in pain after intervention. In the studies including a sample of pain free participants exposed to experimentally induced pain there was an increase in pain threshold when the virtual arm was collocated with the real arm, when it moved in synchrony with the real arm, and when the colour of the stimulated part of the virtual arm became blue. Observing a virtual arm covered with iron armour reduced pain.Conclusions: The use of virtual representations of body parts to reduce pain is promising. However, due to the poor methodological quality and limitations of primary studies, we could not find conclusive evidence.Implications for rehabilitationVirtual reality has been increasingly used in the rehabilitation of painful and dysfunctional limbs.Virtual reality can be used to distract attention away from acute pain and may also provide corrective psychological and physiological environments.Virtual representation of body parts has been used to provide a corrective re-embodiment of painful dysmorphic body parts, and primary research shows promising results.

Transcranial Alternating Current Stimulation at Alpha Frequency Reduces Pain When the Intensity of Pain is Uncertain.

Alpha activity directly before pain onset has been implicated in pain experience with higher prestimulus alpha associated with lower reported pain. However, expectations about pain intensity also seem to affect prestimulus alpha activity. To date, evidence for a relationship between alpha activity and pain experience has been largely correlational. Transcranial alternating current stimulation at alpha frequency (alpha tACS) permits direct manipulation of alpha activity and therefore an examination of the potential causal relationship between alpha activity and pain. We investigated whether somatosensory alpha tACS could reduce pain experience and whether this was influenced by uncertainty about pain intensity. In a within-subjects design, perceived pain intensity and unpleasantness were assessed in 23 participants during alpha tACS and sham stimulation. Visual cues preceding the pain stimulus were used to manipulate uncertainty. A significant tACS × Uncertainty × Stimulus intensity interaction was found for reported pain intensity (F2,44 = 4.50, P = .017, partial η2 = .17) and unpleasantness (F1,22 = 4.78, P = .040, partial η2 = .18). Pain experience during the application of somatosensory alpha tACS was significantly lowered compared with sham stimulation, but only when the intensity of an upcoming stimulus was uncertain. PERSPECTIVE: To our knowledge, this is the first study to suggest that somatosensory alpha tACS might lead to a reduction in pain. Interventions targeting alpha activity may have the potential to alleviate chronic pain. However, a patient's expectation about the intensity of upcoming pain must also be taken into account.

Spatial limits of visuotactile interactions in the presence and absence of tactile stimulation.

The presence of a light flash near to the body not only increases the ability to detect a weak touch but also increases reports of feeling a weak touch that did not occur. The somatic signal detection task (SSDT) provides a behavioural marker by which to clarify the spatial extent of such visuotactile interactions in peripersonal space. Whilst previous evidence suggests a limit to the spatial extent over which visual input can distort the perception of tactile stimulation during the rubber hand illusion, the spatial boundaries of light-induced tactile sensations are not known. In a repeated measures design, 41 participants completed the SSDT with the light positioned 1 cm (near), 17.5 cm (mid) or 40 cm (far) from the tactile stimulation. In the far condition, the light did not affect hit, or false alarm rates during the SSDT. In the near and mid conditions, the light significantly increased hit rates and led to a more liberal response criterion, that is, participants reported feeling the touch more often regardless of whether or not it actually occurred. Our results demonstrate a spatial boundary over which visual input influences veridical and non-veridical touch perception during the SSDT, and provide further behavioural evidence to show that the boundaries of the receptive fields of visuotactile neurons may be limited to reach space.

Changing the size of a mirror-reflected hand moderates the experience of embodiment but not proprioceptive drift: a repeated measures study on healthy human participants.

Mirror visual feedback is used for reducing pain and visually distorting the size of the reflection may improve efficacy. The findings of studies investigating size distortion are inconsistent. The influence of the size of the reflected hand on embodiment of the mirror reflection is not known. The aim of this study was to compare the effect of magnifying and minifying mirror reflections of the hand on embodiment measured using an eight-item questionnaire and on proprioceptive drift. During the experiment, participants (n = 45) placed their right hand behind a mirror and their left hand in front of a mirror. Participants watched a normal-sized, a magnified and a minified reflection of the left hand while performing synchronised finger movements for 3 min (adaptive phase). Measurements of embodiment were taken before (pre) and after (post) synchronous movements of the fingers of both hands (embodiment adaptive phase). Results revealed larger proprioceptive drift post-adaptive phase (p = 0.001). Participants agreed more strongly with questionnaire items associated with location, ownership and agency of the reflection of the hand post-adaptive phase (p < 0.001) and when looking at the normal-sized reflection (p < 0.001). In conclusion, irrespective of size, watching a reflection of the hand while performing synchronised movements enhances the embodiment of the reflection of the hand. Magnifying and minifying the reflection of the hand has little effect on proprioceptive drift, but it weakens the subjective embodiment experience. Such factors need to be taken into account in future studies using this technique, particularly when assessing mirror visual feedback for pain management.

Pre-stimulus alpha oscillations over somatosensory cortex predict tactile misperceptions.

Fluctuations of pre-stimulus oscillatory activity in the somatosensory alpha band (8-14Hz) observed using human EEG and MEG have been shown to influence the detection of supra- and peri-threshold somatosensory stimuli. However, some reports of touch occur even without a stimulus. We investigated the possibility that pre-stimulus alpha oscillations might also influence these false reports of touch - known as tactile misperceptions. We recorded EEG while participants performed the Somatic Signal Detection Task (SSDT), in which participants must detect brief, peri-threshold somatosensory targets. We found that pre-stimulus oscillatory power in the somatosensory alpha range exhibited a negative linear relationship with reporting of touch at electrode clusters over both contralateral and ipsilateral somatosensory regions. As pre-stimulus alpha power increased, the probability of reporting a touch declined; as it decreased, the probability of reporting a touch increased. This relationship was stronger on trials without a somatosensory stimulus than on trials with a somatosensory stimulus, although was present for both trial types. Spatio-temporal cluster-based permutation analysis also found that pre-stimulus alpha was lower on trials when touch was reported - irrespective of whether it was present - over contralateral and ipsilateral somatosensory cortices, as well as left frontocentral areas. We argue that alpha power may reflect changes in response criterion rather than sensitivity alone. Low alpha power relates to a low barrier to reporting a touch even when one is not present, while high alpha power is linked to less frequent reporting of touch overall.

I see how you feel: Recipients obtain additional information from speakers' gestures about pain.

OBJECTIVE: Despite the need for effective pain communication, pain is difficult to verbalise. Co-speech gestures frequently add information about pain that is not contained in the accompanying speech. We explored whether recipients can obtain additional information from gestures about the pain that is being described. METHODS: Participants (n=135) viewed clips of pain descriptions under one of four conditions: 1) Speech Only; 2) Speech and Gesture; 3) Speech, Gesture and Face; and 4) Speech, Gesture and Face plus Instruction (short presentation explaining the pain information that gestures can depict). Participants provided free-text descriptions of the pain that had been described. Responses were scored for the amount of information obtained from the original clips. FINDINGS: Participants in the Instruction condition obtained the most information, while those in the Speech Only condition obtained the least (all comparisons p<0.001). CONCLUSIONS: Gestures produced during pain descriptions provide additional information about pain that recipients are able to pick up without detriment to their uptake of spoken information. PRACTICE IMPLICATIONS: Healthcare professionals may benefit from instruction in gestures to enhance uptake of information about patients' pain experiences.

Brain Areas Involved in Anticipation of Clinically Relevant Pain in Low Back Pain Populations With High Levels of Pain Behavior.

UNLABELLED: The purpose of this study was to identify neural correlates of pain anticipation in people with nonspecific low back pain (NSLBP) that correlated with pain-related distress and disability, thus providing evidence for mechanisms underlying pain behavior in this population. Thirty NSLBP sufferers, with either high levels of pain behavior or low levels on the basis of Waddell signs, were scanned with functional magnetic resonance imaging while a straight-leg raise (of the side deemed to cause moderate pain in the lower back) was performed. On each trial colored stimuli were presented and used to indicate when the leg definitely would be raised (green; 100% certainty), might be raised (yellow; 50% certainty), or would definitely not be raised (red; 100% certainty). In response to expected versus unexpected pain the group difference in activation between patients with high levels of pain behavior and low levels of pain behavior covaried as a function of anxiety scores in the right insula and pregenual anterior cingulate cortex and as a function of catastrophizing in prefrontal and parietal cortex and hippocampus. The results suggest NSLBP populations with the highest levels of pain-related distress are more likely to attend to and infer threat from innocuous cues, which may contribute to the maintenance of pain behavior associated with some chronic pain states. PERSPECTIVE: This article shows a likely neural network for exacerbating pain anticipation in NSLBP contributing to high levels of pain behavior in some people. This information could potentially help clinicians and patients to understand how anticipation of pain may contribute to patient pain and disability.

Somatosensory pleasure circuit: from skin to brain and back.

The skin senses serve a discriminative function, allowing us to manipulate objects and detect touch and temperature, and an affective/emotional function, manifested as itch or pain when the skin is damaged. Two different classes of nerve fibre mediate these dissociable aspects of cutaneous somatosensation: (i) myelinated A-beta and A-delta afferents that provide rapid information about the location and physical characteristics of skin contact; and (ii) unmyelinated, slow-conducting C-fibre afferents that are typically associated with coding the emotional properties of pain and itch. However, recent research has identified a third class of C-fibre afferents that code for the pleasurable properties of touch - c-tactile afferents or CTs. Clinical application of treatments that target pleasant, CT-mediated touch (such as massage therapy) could, in the future, provide a complementary, non-pharmacological means of treating both the physical and psychological aspects of chronic skin conditions such as itch and eczema.

Externalizing the private experience of pain: a role for co-speech gestures in pain communication?

Despite the importance of effective pain communication, talking about pain represents a major challenge for patients and clinicians because pain is a private and subjective experience. Focusing primarily on acute pain, this article considers the limitations of current methods of obtaining information about the sensory characteristics of pain and suggests that spontaneously produced "co-speech hand gestures" may constitute an important source of information here. Although this is a relatively new area of research, we present recent empirical evidence that reveals that co-speech gestures contain important information about pain that can both add to and clarify speech. Following this, we discuss how these findings might eventually lead to a greater understanding of the sensory characteristics of pain, and to improvements in treatment and support for pain sufferers. We hope that this article will stimulate further research and discussion of this previously overlooked dimension of pain communication.

Increased pain intensity is associated with greater verbal communication difficulty and increased production of speech and co-speech gestures.

Effective pain communication is essential if adequate treatment and support are to be provided. Pain communication is often multimodal, with sufferers utilising speech, nonverbal behaviours (such as facial expressions), and co-speech gestures (bodily movements, primarily of the hands and arms that accompany speech and can convey semantic information) to communicate their experience. Research suggests that the production of nonverbal pain behaviours is positively associated with pain intensity, but it is not known whether this is also the case for speech and co-speech gestures. The present study explored whether increased pain intensity is associated with greater speech and gesture production during face-to-face communication about acute, experimental pain. Participants (N = 26) were exposed to experimentally elicited pressure pain to the fingernail bed at high and low intensities and took part in video-recorded semi-structured interviews. Despite rating more intense pain as more difficult to communicate (t(25)  = 2.21, p =  .037), participants produced significantly longer verbal pain descriptions and more co-speech gestures in the high intensity pain condition (Words: t(25)  = 3.57, p  = .001; Gestures: t(25)  = 3.66, p =  .001). This suggests that spoken and gestural communication about pain is enhanced when pain is more intense. Thus, in addition to conveying detailed semantic information about pain, speech and co-speech gestures may provide a cue to pain intensity, with implications for the treatment and support received by pain sufferers. Future work should consider whether these findings are applicable within the context of clinical interactions about pain.

Illness behavior in patients with chronic low back pain and activation of the affective circuitry of the brain.

OBJECTIVE: Patients with chronic low back pain (cLBP) show a range of behavioral patterns that do not correlate with degree of spinal abnormality found in clinical, radiological, neurophysiological, or laboratory investigations. This may indicate an augmented central pain response, consistent with factors that mediate and maintain psychological distress in this group. METHODS: Twenty-four cLBP patients were scanned with functional magnetic resonance imaging while receiving noxious thermal stimulation to the right hand. Patients were clinically assessed into those with significant pain-related illness behavior (Waddell signs [WS]-H) or without (WS-L) based on WS. RESULTS: Our findings revealed a significant increase in brain activity in WS-H versus WS-L patients in response to noxious heat in the right amygdala/parahippocampal gyrus and ventrolateral prefrontal and insular cortex (at a VoxelPThreshold = 0.01). We found no difference between groups for heat pain thresholds (t(22) = -1.17, p = .28) or sensory-discriminative pain regions. CONCLUSIONS: Patients with cLBP displaying major pain behavior have increased activity in the emotional circuitry of the brain. This study is the first to suggest an association between a specific clinical test in cLBP and neurobiology of the brain. Functional magnetic resonance imaging may provide a tool capable of enhancing diagnostic accuracy and affecting treatment decisions in cases where no structural cause can be identified.

Pain ratings reflect cognitive context: a range frequency model of pain perception.

When painful stimuli are evaluated at the time they are experienced, judgments are made not in isolation but with reference to other experienced stimuli. We tested a specific quantitative model of how such context effects occur. Participants experienced 3 blocks of 11 different pressure pain stimuli, and rated each stimulus on a 0-10 scale of intensity. Stimulus distribution was varied between participants. Study 1 found that that the rating of a stimulus of a particular pressure was higher in the context in which it ranked highest. Study 2 found that pain ratings were higher in a context where most stimuli were relatively intense, even when the mean stimulus was constant. It is suggested that pain judgments are relative, involve the same cognitive processes as are used in other psychophysical and socioemotional judgments, and are well described by range frequency theory. This approach can further inform the existing body of research on context-dependent pain evaluation.

Pleasant touch moderates the subjective but not objective aspects of body perception.

Un-myelinated C tactile afferents (CT afferents) are a key finding in affective touch. These fibers, which activate in response to a caress-like touch to hairy skin (CT afferents are not found in palm skin), may have more in common with interoceptive systems encoding body ownership, than afferent systems processing other tactile stimuli. We tested whether subjective embodiment of a rubber hand (measured through questionnaire items) was increased when tactile stimulation was applied to the back of the hand at a rate optimal for CT afferents (3 cm/s) vs. stimulation of glabrous skin (on the palm of the hand) or at a non-optimal rate (30 cm/s), which should not activate these fibers. We also collected ratings of tactile pleasantness and a measure of perceived limb position, proprioceptive drift, which is mediated by different mechanisms of multisensory integration than those responsible for feelings of ownership. The results of a multiple regression analysis revealed that proprioceptive drift was a significant predictor of subjective strength of the illusion when tactile stimuli were applied to the back of the hand, regardless of stroking speed. This relationship was modified by pleasantness, with higher ratings when stimulation was applied to the back of the hand at the slower vs. faster stroking speed. Pleasantness was also a unique predictor of illusion strength when fast stroking was applied to the palm of the hand. However, there were no conditions under which pleasantness was a significant predictor of drift. Since the illusion was demonstrated at a non-optimal stroking speed an integrative role for CT afferents within the illusion cannot be fully supported. Pleasant touch, however, does moderate the subjective aspects of the rubber hand illusion, which under certain tactile conditions may interact with proprioceptive information about the body or have a unique influence on subjective body perception.

Brief body-scan meditation practice improves somatosensory perceptual decision making.

We have previously found that attention to internal somatic sensations (interoceptive attention) during a heart beat perception task increases the misperception of external touch on a somatic signal detection task (SSDT), during which healthy participants erroneously report feeling near-threshold vibrations presented to their fingertip in the absence of a stimulus. However, it has been suggested that mindful interoceptive attention should result in more accurate somatic perception, due to its non-evaluative and controlled nature. To investigate this possibility, 62 participants completed the SSDT before and after a period of brief body-scan mindfulness meditation training, or a control intervention (listening to a recorded story). The meditation intervention reduced tactile misperception and increased sensitivity during the SSDT. This finding suggests that the perceptual effects of interoceptive attention depend on its particular nature, and raises the possibility that body-scan meditation could reduce the misperception of physical symptoms in individuals with medically unexplained symptoms.

Dialysis and sexuality.

End stage renal disease is a major health issue in the United States. Dialysis, the major form of renal replacement therapy, has physical and psychological implications that can have a major impact on both men's and women's sexuality and sexual performance. Nurses are in a key position to assist men and women on dialysis to develop healthy and realistic approaches to their sexuality. This article reviews the literature on dialysis and sexuality, and recommends nursing interventions that can assist persons on dialysis achieve the level of sexual intimacy and satisfaction they desire.

Role of functional brain imaging in understanding rheumatic pain.

Rheumatic pain and, in particular, rheumatoid arthritis, osteoarthritis and fibromyalgia, are common and debilitating chronic pain syndromes. Recently, human functional neuroimaging, for example EEG, fMRI, and PET has begun to reveal some of the crucial central nervous system mechanisms underlying these diseases. The purpose of this review is to summarise current knowledge on the brain mechanisms of rheumatic pain revealed by functional neuroimaging techniques. The evidence suggests that two mechanisms may be largely responsible for the clinical pain associated with these rheumatic diseases: abnormalities in the medial pain system and/or central nervous system sensitisation and inhibition. If we can understand how functioning of the central nociceptive system becomes altered, even in the absence of peripheral nociceptive input, by using functional neuroimaging techniques, in the future we may be able to develop improved, more effective treatments for patients with chronic rheumatic pain.