Coma Symptoms & Diagnosis

Symptoms

Symptoms of a coma include the following:

No response to outside stimuli, such as:
- Pain
- Sound
- Touch
- Sight
Spontaneous body movements, such as:
- Jerking
- Shaking
- Trembling
- Eyes opening and closing
- Irregular breathing

Diagnosis

Since the patient cannot speak, information from friends, family members, and witnesses is important when diagnosing the cause of a coma. The doctor will want to know about the person’s medical history, as well as any drug or alcohol use. It is important to provide honest information in order to help with treatment.

The doctor will test reflexes, listen to breathing, examine the eyes, and perform neurological and physical exams. In addition, the following tests may be done:

Blood tests—to check blood glucose levels, organ function and screen for infection and toxic substances
Urine test—to test for the presence of drugs
Imaging tests, such as:
- Neck x-rays —in cases where head and neck trauma may have occurred, a test that uses radiation to take pictures of structures inside the body
- MRI scan —a test that uses magnetic and radio waves to make pictures of the inside of the body, in this case the brain
- CT scan —a type of x-ray that uses a computer to make pictures of the inside of the head
- SPECT or Xenon—enhanced CT scan to test for blood flow and metabolic activity within the brain
Electroencephalogram (EEG) —a test that records the brain's activity by measuring electrical currents through the brain
Spinal tap (lumbar puncture) —removal of a small amount of cerebrospinal fluid to check for pressure, blood, and infection
Evoked potentials—a test for brain wave activity after stimulation of the sensory nerves of the body

Comas are rated according to the Glasgow Coma Scale (GCS), which assesses three different functions: eye opening, motor response, and verbal response. Scores can range from 15 to 3. A lower score indicates a person is less responsive. Scores are interpreted as follows:

15-13—mild brain injury
12-9—moderate brain injury
8 or less—a severe brain injury

Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition. Copyright © 2026 EBSCO Publishing All rights reserved.