Contents lists available at ScienceDirect Journal of Electromyography and Kinesiology journal homepage: www.elsevier.com/locate/jelekin Bridging the gap between temporomandibular disorders, static balance impairment and cervicogenic dizziness: Posturographic and clinical outcomes Andrea Viziano a, ⁎ , Alessandro Micarelli b,c , Pasquale Carlino b , Ivan Granito b , Marco Alessandrini a a University of Rome Tor Vergata, Department of Clinical Sciences and Translational Medicine, Italy b ITER Center for Balance and Rehabilitation Research (ICBRR), Rome, Italy c Institute of Mountain Emergency Medicine, Eurac Research, Bolzano, Italy ARTICLE INFO Keywords: Temporomandibular disorders Cervicogenic dizziness Cervical range of motion Posturography Spectral analysis Spine movement ABSTRACT Several studies have investigated the possible influence of temporomandibular disorders (TMD) on body posture and whether cervical spine disorders, such as cervicogenic dizziness (CGD) could play an additional role in affecting static balance. The purpose of this study was to analyze static postural behavior by means of static posturography, in patients affected by either TMD or CGD alone or by both conditions, and to compare findings with a group of healthy subjects. Significant changes in posturographic parameters were found among the three groups of patients and when compared with controls. When the three study groups were compared to each other, subjects affected by a combination of TMD and CGD showed worse postural performances with respect to subjects affected by CGD or TMD alone. Correlations with self-perceived dizziness, anxiety, depression and jaw functionality, investigated by means of validated questionnaires, were found among all patient groups. These results provide new evidences for the presence of static balance alterations in patients suffering from TMD with and without associated cervical spine impairment, by using a reliable diagnostic technique. Further studies are needed in order to identify any causal relation between these two disorders. 1. Introduction Clinical conditions involving the masticatory muscles and/or tem- poromandibular joints and associated structures have been collectively defined as temporomandibular disorders (TMD) (Nota et al., 2017). TMD originate from biomechanical, neuromuscular and biopsychoso- cial factors (Xu et al., 2018): due to such multifactorial etiopathogen- esis, disease definition is not unequivocal; TMD are generally divided between muscle-related (or myogenous) and related to joint dysfunc- tion (arthrogenous), mainly according to the presence or absence of destructive joint changes on radiograph (Jerjes et al., 2008; Nota et al., 2017). Several studies have investigated the possible influence of stoma- tognathic disorders on body posture, especially as regards symptoms overlapping with cervical spine dysfunction, such as dizziness, cervical pain, and muscle fatigue (Baldini et al., 2013; Borges et al., 2018; Rocha et al., 2013). A correlation between TMD and cervical posture has been highlighted by a literature review and indirect experimental evidences concluded subjects with TMD showed limited cervical spine mobility (Grondin et al., 2015; Nota et al., 2017; Walczynska-Dragon et al., 2014); however, other studies have pointed out that, for example, unilateral temporomandibular disk displacement does not seem to af- fect body posture (Rocha et al., 2017), and evidence could be biased by focusing exclusively on subjects with joint pain, which can then drive cervical postural adaptations (Manfredini et al., 2012). This led to hy- pothesize that the presence of pain may provoke a demand for cervical postural adaptations and thus postural changes may represent the ef- fects rather the cause for the symptoms (Manfredini et al., 2012). When facing neurophysiological connections between the cervical spine and temporomandibular area, showing the convergence of af- ferent inputs and multiple reciprocal influences of masticatory and neck muscle activity (Hu et al., 2005; Svensson et al., 2005), it remains unclear which extent of a common clinical field may be shared by TMD and cervical spine disorders, such as cervicogenic dizziness (CGD). This is a motion sensation characterized by the presence of imbalance, un- steadiness, disorientation, neck pain, limited cervical range of motion https://doi.org/10.1016/j.jelekin.2020.102455 Received 18 May 2020; Received in revised form 22 July 2020; Accepted 1 August 2020 ⁎ Corresponding author at: Department of Clinical Sciences and Translational Medicine, University of Rome 'Tor Vergata', Via Montpellier, 1, E sud Tower, 00133 Rome, Italy. E-mail address: andrea.viziano@gmail.com (A. Viziano). Journal of Electromyography and Kinesiology 54 (2020) 102455 1050-6411/ © 2020 Elsevier Ltd. All rights reserved. T