Proprioception in somatoform disorders

Somatoform dissociation and somatosensory amplification are differentially associated with attention to the tactile modality following exposure to body-related stimuli

“…Moreover, one nonclinical study found that high SSAS scorers were actually less able to detect bodily sensations (heartbeats) than low scorers, suggesting a decreased somatosensory sensitivity in this group [23]. In contrast, Scholz et al [24] found that patients with somatoform disorders were more accurate than healthy controls at estimating their muscle tension during a biofeedback task.…”

Evidence that subclinical somatoform dissociation is not characterised by heightened awareness of proprioceptive signals

“…Paradigms investigating both interoceptive and proprioceptive awareness have sought to offer some insight into how these sensory signals are processed in those experiencing medically unexplained symptoms and somatoform disorders. Using an EMG-biofeedback task to investigate proprioceptive abilities, Scholz, Ott, & Sarnoch (2001) found that patients with somatoform disorder showed more precise proprioception for muscle tension than a control group, lending support to the suggestion of heightened body awareness in somatoform disorders. However there were no differences in subjective ratings of perceived intensity of proprioception between the two groups, as the amplification account would predict.…”

“…However, this finding could be accounted for by two alternative explanations. On one hand, it may be that the high-SDQ group had a greater awareness of the real position of their hidden limb, through increased body awareness or more precise proprioception (Scholz et al, 2001). In the rubber hand illusion, increased proprioceptive awareness could result in this sense being weighted more strongly than visual and tactile inputs during multisensory integration.…”

“…During the rubber hand illusion, in which there is a discrepancy between visuo-tactile and proprioceptive information, an increased reliance on proprioception could lead to a more stable and accurate sense of body position and, subsequently, reduced illusory experience. Whilst the paradigm used by Scholz et al (2001) was designed to investigate proprioceptive muscle accuracy, no studies have investigated specifically how proprioceptive information is integrated in those susceptible to somatoform dissociation. Therefore the aim of the current experiment was to test the hypothesis that people scoring highly on the Somatoform Dissociation Questionnaire would weight proprioceptive information more strongly under conditions of multisensory conflict.…”

“…Participants completed a hand localisation task following the introduction of a covert discrepancy between the visual and proprioceptive location of the hand. Based on the findings of Scholz et al (2001) and the apparently more stable sense of body position observed in the high symptom group in the Miles et al (2011) study, it was hypothesised that high symptom reporters would be more accurate at locating the position of their hidden hand following manipulation. Since reliance on proprioceptive information has been shown to increase when visual information about hand position is degraded or occluded (Bellan et al, 2015;Mon-Williams, Wann, Jenkinson, & Rushton, 1997;Welch & Warren, 1980), we also investigated perceptual drift across time in low and high symptom groups to further clarify the proprioceptive abilities in those susceptible to medically unexplained symptoms.…”