Mild Traumatic Brain Injury Classification Encompasses a Broad Range of Patients

A metaphoric illustration about brain damage.
The broad definition of mild traumatic brain injury (TBI) suggests there is need for defining distinct subgroups of TBI.

The broad definition of mild traumatic brain injury (TBI) has led the authors of an observational cohort study to conclude there is need for defining distinct subgroups of TBI, according to study findings published in BMJ Open.

Researchers sourced data for this study from 7 hospitals in Germany. They assessed patients (N=3514) who suffered from a TBI between 2014 and 2015 for causes, symptoms, care received, and clinical outcomes through 12 months.

Patients had a mean age of 54.5 (standard deviation [SD], 22.6) years and 59.2% were men. The International Statistical Classification of Diseases, Tenth Revision diagnoses were S06.0 (37.4%), S00.9 (18.6%), S02.9 (11.2%), S06.6 (7.5%), S06.5 (5.6%), S06.7 (3.3%), S06.9 (3.3%), S06.2 (1.7%), S06.3 (1.6%), S06.8 (1.2%), S06.4 (0.9%), S06.1 (0.4%), missing (6.6%), or other (0.9%).

Initial prehospital Glasgow Coma Scale (GCS) severity was classified as mild (85.1%), severe (7.7%), and moderate (7.2%). At the emergency department, GCS severity was classified as mild (87.3%), moderate (3.3%), and severe (2.3%).

TBIs were most frequently caused by falls, traffic accidents, and external force. There was a significant association of age (P =.019) and cause of TBI (P <.001), in which patients who were over 50 years were most likely to have fallen (71.3%), and patients aged 50 years or younger had TBI due to external force (30.6%), traffic accidents (29.0%), and falls (27.3%). Alcohol was involved with 14.4% of TBIs.

A third of patients (35.5%) were admitted to the intensive care unit and 47.6% of those patients required surgical intervention.

Rehabilitation care comprised physiotherapy (46.5%), speech therapy (5.9%), occupational therapy (4.7%), and neuropsychological therapy (3.1%).

At discharge, 22.3% said they were experiencing subjective symptoms such as headache (18.6%) and dizziness (10.2%). 13.1% had neurological deficits.

Most patients were discharged to home (69.6%), 12.4% to a rehabilitation unit, 7.5% to another acute hospital, and 4.1% to a nursing home. Mortality due to TBI, cerebral complications, cardiac complications, pulmonary complications, or infection occurred among 4.3%.

During a telephone interview at 12 months, 35.3% said they still had difficulties due to their TBI and 7.6% had changed their occupation because of their TBI.

Risk for lingering TBI symptoms was increased among patients who had intracranial bleeding (odds ratio [OR], 2.76) and GCS 13 or 14 (OR, 1.82). Risk was decreased among men (OR, 0.62) or patients who had been intoxicated with alcohol (OR, 0.45).

This study was limited by its broad, simplified definition of TBI which included patients who had a head injury without any sign of brain dysfunction.

These data indicated that there were multiple types of mild TBI, likely indicating a need for defining distinct subgroups of TBI such that individuals who are at risk for long-term effects may be more easily identifiable.


Schwenkreis P, Gonschorek A, Berg F, et al. Prospective observational cohort study on epidemiology, treatment and outcome of patients with traumatic brain injury (TBI) in German BG hospitals. BMJ Open. 2021;11(6):e045771. doi:10.1136/bmjopen-2020-045771