Oral Biting Relatively Specific to Motor Tonic or Tonic-Clonic Seizures

Although severe biting injuries are uncommon, tongue and oral injuries are often very unpleasant and should be considered in an informed consent discussion about medication withdrawal for seizure evaluation.

A chart review of patients with epilepsy at the Cleveland Clinic in Ohio found that oral biting and its associated lacerations are frequently reported in the epilepsy, with the injury being relatively specific to motor tonic or tonic-clonic seizures. Findings from this review were published in Seizure.

Study investigators performed a chart review of adult patients with epilepsy who underwent seizure monitoring at the Cleveland Clinic epilepsy monitoring unit. A total of 52 patients were included.

Researchers identified oral biting events, including the number of events and locations. The location of tongue laceration was correlated with demographic (age, sex, handedness), diagnostic, and seizure-related (epilepsy vs nonepileptic seizures, primarily generalized vs focal, electroencephalogram onset, clinical onset, semiology, ictal position) data obtained from both medical records and video electroencephalogram recordings. In addition, the researchers evaluated lateralized oral lacerations while recumbent.

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In the total cohort, 89 oral biting events were reported, representing 5.6% of admissions or 8.3% of patients who had epileptic seizures. Lacerations were recorded in 80 generalized seizures, 3 focal seizures, 5 seizures of unknown etiology, and 1 nonepileptic seizure. A tonic and clonic component of seizures were recorded in 87 and 86 seizures, respectively.

More than half the patients (n=30) had an observable lateralized tongue laceration. Although lacerations correlated with body position during the event, no association was found with handedness or characteristics of seizures.

The side of tongue biting was associated with the dependent side in patients who were in a lateral decubitus position (P =.004).

Limitations of the study include the small sample size, as well as the recruitment of individuals from a single center, which may limit generalizability of the findings.

“While this study disproves previous impression that lateralization of tongue injury in a seizure may be useful in lateralizing a seizure focus, it supports the fact that this type of injury is relatively specific to motor tonic or tonic-clonic seizures,” the study researchers concluded.


Dufresne D, Dubovec K, So NK, Kotagal P. Ictal biting injuries in the epilepsy monitoring unit, a cohort study of incidence and semiological significance. Seizure. 2019;66:39-41.