The main finding of the present study is that adolescents with episodic migraine had significantly lower tendency to seek sensory input compared to healthy controls.
Although both groups did not significantly differ in sensory sensitivity and avoidance, the prevalence of adolescents with migraine found above norm values in both of these sensory patterns was twice higher. We have demonstrated that sensory avoidance was a predictor of migraine related disability, as reflected in the PedMIDAS score.
The possible connection between migraine and sensory processing patterns as expressed in daily living scenarios among patients with migraine has only rarely been reported. Nahman-Averbuch et al. [25] in a meta-analysis study, revealed a lower heat and pressure pain thresholds and higher pain ratings to cold stimuli, among patients with migraine. The perception of sensory stimuli such as sound, light, odors and somatosensory stimuli tend to be enhanced among patients with migraine [16, 26-28] between migraine attacks and might even be a trigger to migraine attacks. Coppola et al, [29] found abnormal cortical responses to light and Sand et al. [30] demonstrated, that different high frequency oscillations of the somatosensory evoked potential among migraine patients compared to controls. Noseda [31] found habituation difficulties among patients with migraine, as well as enhanced sensory sensitivity, using Quantitative Sensory Testing (QST) noting that patients with migraine may have greater reactivity to pain.
Studies about SPD in children also found habitation difficulties as measured in the Short Sensory Profile questionnaire [32] and in electrophysiological measures such as the electrodermal reactivity (EDR) [33]. Similar results were found in adults with SPD as manifested by the AASP and evoked response potentials [34].
These findings support the hypothesis that patients with migraine have abnormalities in sensory processing and integration [35]. Recently, Goadsby [36] found that both the aura and the migraine attack, may represent a form of hypersensitivity due to sensory processing difficulties. Mainero et al. [37] demonstrated that patients with migraine have stronger connectivity between the ventrolateral periaqueductal gray (PAG) and other brain areas that are involved in nociceptive and somatosensory processing. Other authors [38] suggested that sensory hypersensitivity may result from activation of subcortical brain areas receiving convergent inputs and then project to different cortical brain areas involved in integrating multiple sensory modalities such as visual, auditory and olfactory. As suggested by Tommaso et al., [35] studies should further explore sensory processing in patients with migraine. These studies should implement objective measures such as neuroimaging to reflect temporal patterns of sensory processing in patients with migraine and correlated them with the accompanying anatomical and functional changes.
Yet, these findings are related to adults with migraine, and less is known about extreme sensory processing among younger patients with migraine. In a previous study [18] we also found that young children (6-12 years of age) with migraine had greater prevalence of extreme sensory processing patterns, expressed in hypersensitivity, which also correlated with their low quality of life. The negative effects that extreme sensory processing patterns may have on daily function [39] and quality of life [18], and their prevalence among children, emphasize the need to elaborate the knowledge about this relationship in adolescents as well and explore the association between sensory processing patterns, pain experience – catastrophization and related disability.
In the present study, the pain catastrophizing scale for children (PCS-C) was used to measure the functional and psychological consequences of pain among adolescents with migraine. Catastrophizing about pain is a critical variable in how we understand adjustment to pain and has a unique contribution in predicting pain intensity. The theoretical bases were defined by Sullivan et al. [9] who considered catastrophizing as a part of the appraisal model [40] that described rumination and magnification as primary appraisal processes in which patients place emphasis on the fear from pain sensations. Helplessness is related to secondary appraisal processes in which patients under evaluate their ability to manage pain effectively. Magnification and rumination usually cause pain avoidance.
In the present study, among adolescents with migraine, pain magnification correlated with sensory avoidance, probably because both factors represent the same hypersensitivity - to non-aversive stimuli of daily scenarios as well as to painful stimuli. A main characterizes of individuals with sensory hypersensitivity is their magnification of the sensation, the inability to control the overwhelming sensation and adapt to it similar to people with pain catastrophizing [8]. In line with the "Appraisal Model" [41] the ineffective coping with threatful sensory stimuli and the inability to use effective coping strategy to manage and adapt to this inconvenience, characterizes both individuals with pain catastrophizing, with sensory hypersensitivity [42] , and thus in individuals with migraine.
Recently, Sciruicchio et al [12] evaluated pain catastrophizing among children with migraine and found no difference in total pain catastrophizing score (PCS-C) between children with episodic versus chronic migraine. In our study, adolescents with episodic migraine had significantly higher rates of rumination and helplessness and this may affect their pain experience, fear and lead to lower tendency to seek for sensory input. Sciruicchio et al [12] also reported that PCS-C did not correlate with the PedMIDAS score. In our study migraine severity correlated with elevated rumination. It might be effective to refer to the PCS-C scales and not only to the total scores, in order to better understand what are the pain catastrophizing parameters that play a role in migraine. How they are related to other characteristics of individuals with migraine, such as their sensory processing patterns, and how it is related to their daily function.
These findings, together with our current report on the connection between migraine and sensory avoidance, raises a new prospective to migraine treatment in adolescents. Intervention programs should consider anxiety or depressive disorders and other forms of psychopathology in adolescence with migraine [43-45] with respect to extreme sensory processing patterns. The extreme sensory processing patterns may be related to the low academic performance and school refusal, as well as with somatic and emotional complaints in adolescents with migraine [46]. Intervention, focusing on coping strategies to deal with pain perception and the extreme sensory processing patterns as expressed in daily scenarios should be applied to optimize function and quality of life. By that, the negative consequences of migraine and related difficulties in terms of social, academic and personal adjustment may be reduced [47-48].
Limitations: The study consisted on a relatively small sample. Although patterns of sensory sensitivity and avoidance were not significantly different between both groups, the larger children with migraine found above norms in these patterns, raise the need to further examine the relationships between these sensory patterns and pain perception on larger samples in order to enable generalizability of the results.