Research has predominantly classified fibromyalgia as a condition of disturbed pain processing suggested to reflect a general central sensitisation of the nervous system (Cagnie et al., 2014). Emerging evidence, however, suggests that disturbances in pain processing may also extend to different sensory modalities. For example, clinically, fibromyalgia sufferers report symptoms of increased sensitivity to sounds, lights and smells. Furthermore, in an experimental setting, research shows that across modalities, patients with fibromyalgia demonstrate increased noxiousness to sensory stimuli or a reduction in the intensity of a stimulus required to create an unpleasant or overwhelmed response, which we will collectively refer to as tolerance (e.g., McDermin, Rollman, & McCain, 1996; Geisser et al., 2008; Schweinhardt, Sauro, & Bushnell, 2008; Wilbarger & Cook, 2011). Evidence of increased sensitivity (e.g., reduced tolerance to sensory stimuli) across modalities has led to the suggestion that fibromyalgia may reflect a global disturbance in sensory processing (Geisser et al., 2008).
While patients may experience sensory hypersensitivity in one aspect of perception (indicated by reduced tolerance), research in the touch and pain modality of chronic pain conditions suggests that this may not transfer to other aspects of sensory processing. For example, patients with fibromyalgia display higher tactile temporal discrimination thresholds, indicative of an impairment, and a reduced accuracy in detecting internal bodily sensations which correlates with symptom severity (Gunendi, Polat, Vuralli, & Cengiz, 2019; Duschek, Montoro, & Reyes del Paso, 2017). Based on these findings, hypersensitivity to pain in fibromyalgia can be reasoned to be associated with impaired basic bodily perception in the pain and touch modality. Limited research has studied detection and discrimination abilities in fibromyalgia across modalities. The overall aim of the current study is to therefore investigate different aspects of sensory processing across sensory modalities in fibromyalgia via self-report methods.
Several self-report questionnaires have been developed to measure different aspects of sensory processing in clinical populations. These include the sensory perception quotient (SPQ) (Tavassoli, Hoekstra, & Baron-Cohen, 2014) and the sensory hypersensitivity scale (SHS) (Dixon et al., 2016). The SPQ was designed to measure basic perception by asking about specific abilities including discrimination and detection ability across five different sensory modalities in adults with autism (e.g., touch, hearing, vision, smell and taste). In contrast, the SHS was designed to serve as a proxy measure for central sensitisation and contains questions relating to increased noxiousness to sensory stimuli (which we refer to as tolerance) across nine separate subscales (e.g., allergies, heat, cold, light, pain, smell, hearing, taste and touch). In a fibromyalgia population, tolerance was found to be reduced relative to healthy controls across the nine modalities.
The first aim of this study is to compare fibromyalgia patients and healthy controls on both the SHS and the SPQ as they were originally developed. This will allow us to explore how our population compares to previous studies as well as informing whether any differences between groups are modality specific or more general.
To investigate how different aspects of perception are affected in fibromyalgia across modalities, the second aim of this study is to attempt to validate a new scale (containing questions from the SPQ and SHS) measuring three different aspects of perception (detection, discrimination and tolerance). For the purpose of this study, detection is defined as the ability to identify a stimulus (e.g., I would feel if a single hair touched the back of my hand). Discrimination refers to the ability to discriminate between stimuli (e.g., I would be able to taste the difference between two brands of salty potato chips/crisps). Finally, tolerance refers to the perceived sensitivity to a stimulus (e.g., I am sensitive to bright lights).

plus-circle Add Review

comment

Reviews