Oromandibular dystonia, mental distress and oro-facial dysfunction-A follow-up 8-10 years after start of treatment with botulinum toxin.

[BACKGROUND] Oromandibular dystonia (OMD) with involuntary jaw and tongue movements may be misdiagnosed as temporomandibular disorders (TMD) and because of the complex muscle activity and involvement of several small muscles, OMD is also considered difficult to treat.

[OBJECTIVES] The aim was to evaluate OMD in patients 8-10 years after start of treatment with botulinum toxin (BoNT) by self-reported and standardised global scales and questionnaires.

[METHODS] Of 21 previously reported patients with OMD, 14 responded to a mail health questionnaire to describe the disease course and treatment effect as well as the overall impact of OMD by a visual analogue scale (VAS), the Patient Health Questionnaire (PHQ) for depression and anxiety, and the Jaw Functional Limitation Scale (JFLS). The results were analysed with non-parametric statistical analysis (Wilcoxon matched-pairs test and Spearman's rank-order correlations).

[RESULTS] The OMD was still present in 13 patients. In nine patients, the BoNT treatment had continued as monotherapy or combined with oral medication. VAS for OMD was significantly reduced (P < 0.04) over the years, and most patients felt improvement from the treatment. However, the patients had still some functional limitations, typically regarding jaw mobility and communication, and both JFLS and mental distress (PHQ) were significantly correlated with the OMD VAS (r 0.77 and 0.74).

[CONCLUSION] The results showed marked reduction of the experienced OMD with treatment and over time, and also stressed similarities between OMD and TMD. Both dentists and neurologists should be aware of this overlap and reduce misdiagnosis by applying an interdisciplinary approach.