Occurrence, presence and severity of bruxism and its association with altered state of consciousness in individuals with severe acquired brain injury.

OBJECTIVE Excessive jaw muscle activity is a frequent complication after acquired brain injury (ABI). The study aimed to identify the occurence and severity of jaw muscle activity and its association with altered state of consciousness in patients with ABI. METHODS A total of 14 severe ABI patients with varied altered state of consciousness were recruited. A single-channel electromyographic (EMG) device was used to assess the jaw muscle activity for three consecutive nights during week 1 and week 4 following admission. Differences in number of EMG episodes/hr between week 1 and 4 were analyzed using non-parametric tests and association between the EMG activity and altered state of consciousness were analyzed using Spearman´s correlation test. RESULTS 9/14 (64%) of patients showed indications of bruxism (cut-off: >15 EMG episodes/hr). The average EMG episodes/hr at admission were 44.5±13.6 with no significant changes after week 4 of admission (43±12.9; P=0.917). The EMG episodes/hr ranged from 2-184 during week 1 and 4-154 during week 4. There were no significant correlations between the number of EMG episodes/hr during the 3 nights and the individuals altered state of consciousness during week 1 and week 4. CONCLUSION Patients with ABI had a conspiciously high but variable level of jaw muscle activity at admission and it tend to remain high after 4 week of hospitalization which could potentially lead to adverse effects such as excessive tooth wear, headaches and pain in jaw muscles. The lack of associations between individuals altered level of consciousness and EMG activity could be due to low sample size and further studies are clearly warranted in this patient group with special needs. Single-channel EMG devices can record jaw muscle activity early in the hospitalization period and might be a helpful tools for early detection of bruxism in ABI patients.