Chewing in patients with severe neurological impairment Merete Bakke a, *, Eigild Møller b , Carsten Eckhart Thomsen a , Torben Dalager b , Lene Maria Werdelin b a Department of Oral Medicine, Section of Clinical Oral Physiology, Faculty of Health Sciences, University of Copenhagen, 20 No ¨ rre Alle ´, DK-2200, Copenhagen N, Denmark b Department of Neurology and Clinical Neurophysiology, Bispebjerg University Hospital, 23 Bispebjerg Bakke, DK-2400 Copenhagen NV, Denmark 1. Introduction Mastication is rhythmic with cycles divided in a jaw-opening phase and a jaw-closing phase with a slow power stroke at the end. Accordingly, jaw depressors and elevators alternate in a typical pattern. 1 The basic masticatory pattern is controlled by a central pattern generator in the brainstem, supplemen- ted by centres in the motor cortex and the basal ganglia, and modified by peripheral information from the masticatory system. 2–4 Degenerative disease, and lesions, infarction and haemorrhage involving these areas in the CNS may have profound effect on mastication and mandibular function. Knowledge of the resulting changes in the function is important for our understanding of mastication and its motor control. However, few studies have been published with focus on such changes. 5,6 The present case series deals with chewing disturbances resulting from neurological impairment, and the aim was to classify and analyse such disturbances associated with various diagnoses. 2. Material and methods The case series consisted of 10 patients referred to the School of Dentistry and Bispebjerg Hospital Centre for Movement Disorders, University of Copenhagen, for diagnosis and treatment (Table 1). They had neurological disorders, but no significant mental deficiencies, and were examined with standard procedures by a multidisciplinary team. The patients or their family consented to that their data were used anonymously for publication. After verification of their CNS lesions by MR-scanning and of temporomandibular joint normality by radiographic examination, the patients were classified according to their chewing disturbance. The archives of oral biology 52 (2007) 399–403 article info Article history: Accepted 15 January 2007 Keywords: Mastication Trismus Masticatory muscles Electromyography Case series abstract Objective and design: As degenerative disease, infarction and hemorrhage in the CNS may compromise chewing, the aim was to classify and analyse such chewing disturbances. The case series included clinical and electromyographic recordings from 10 patients (ages 12–78 years) with neurological disorders. Results: Classifications were involuntary munching (two women with dystonia which was abolished during mastication), ceased chewing function (three men with impaired volitional motor control and spasticity from locked-in syndrome, restricted chewing range (two men and one woman with reduced jaw opening due to paradoxical activity after brainstem lesions), and distorted chewing pattern (two men with dystonia resulting in blockings during chewing). Conclusion: The effect of the neurological impairment illustrated the complex control of mastication and the interaction between central and peripheral mechanisms, and the variation of the chewing disturbances was surprisingly great, even with similar diagnosis. # 2007 Elsevier Ltd. All rights reserved. * Corresponding author. Tel.: +45 35 326554; fax: +45 35 326569. E-mail address: mb@odont.ku.dk (M. Bakke). available at www.sciencedirect.com journal homepage: www.intl.elsevierhealth.com/journals/arob 0003–9969/$ – see front matter # 2007 Elsevier Ltd. All rights reserved. doi:10.1016/j.archoralbio.2007.01.003