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DAN® On-site DCI Neurological Exam

Divers with decompression illness (DCI) may have some damage to the nervous system. The signs are often vague and they can cause delays in effective treatment if they go unnoticed.

This guide explains what DAN neurological assessment is, and how to perform a 5 minute neurological exam on an injured diver with suspected DCI.

What is a DCI Neurology Observation Test?

Learning how to quickly examine an injured diver's nervous system can influence the initial treatment administered by medical personnel.

Thus, information gathered soon after all scuba diving accidents will be vital for a physician's diagnosis and response.

Put another way:

Being able to make a few simple observations about an injured diver's sensory reactions can help to determine the initial course of treatment and its effectiveness.

So, how easy is it for a rescuer to conduct a basic neurological DCI test and check for the common symptoms of decompression illness (e.g. unusual fatigue, pain in the joints, shortness of breath)?

In fact, some of the main objectives include seeing how the diver responds to their whereabouts and whether they are having problems with balance and coordination.

Pro Tip: The DCI neuro test for muscle strength and body coordination is most important. Hence, give priority to this part of the evaluation if you are unable to perform the comprehensive DAN® On-site Neurological Exam.

DCI Examination and Observations

The On-site Neurological Exam, developed by the Divers Alert Network (DAN), is not difficult to learn. In fact, even individuals without any medical experience should find it easy to conduct the five minute medical analysis.

You can use this detailed guide to practice testing for DCI symptoms on a healthy diver and under non-emergency conditions. But, it is important to perform the dry run in the correct order (e.g. starting with the orientation).

Step 1. Basic Orientation

Ask a diver with suspected decompression illness (DCI) to tell you (all):

Important: Some divers with DCI may still appear to be alert. But, answering these simple questions about their whereabouts can reveal typical signs of confusion. You should not omit them!

Step 2. Eye Movement

Check if the diver has any difficulty counting the number of fingers that you display in front of their eyes. You can start with two (2) and they try the same test with three (3) or more fingers.

It's important to check each eye for smooth tracking separately at first - and then see if they move together. You can also get them to identify a distant object (e.g. dive flags and floats). See if they are able to read a few printed words on the distant object with both eyes (one eye at a time).


Ask the diver not to move their head (or you might hold it steady for them) and get them to follow your hand with their eyes while you move your hand from side to side and up and down around 45 cm (18 inches) in front of their face. There should be no jerky eye movement and the pupils should be about the same size.

Step 3. Facial Sensations

Their face should have the same expression on each side when they purse their lips (e.g. turn down the corners of the mouth). When they grit their teeth together, the jaw muscles should contract together.

Ask the diver to close the eyes while you touch across their face and forehead with your fingertips. You're trying to determine if they have the same sensation everywhere or are they showing some signs of facial paralysis.

Step 4. Hearing Evaluation

Pro Tip: What if the surroundings are noisy? If so, you can ask bystanders to be quiet and to turn off any unused machinery, but you still may need to skip this part of the analysis.

Step 5. Swallowing Reflex

Ask the diver with suspected DCI to swallow while you watch the movement of the "Adam's apple" (easier in male divers). It should move up and down as a normal response when swallowing.

Step 6. Tongue Straightness

Ask them to stick out their tongue. You want to check that it comes out straight and in the middle of the mouth. If the tongue deviates to either side of the mouth it could be an indication of facial paralysis.

Step 7. Muscle Strength

Instruct the diver to shrug shoulders while you bear down on them to observe for equal muscle strength. Check the diver's arms by bringing the elbows up level with the shoulders, hands level with the arms and touching the chest.

Get them to resist while you pull the arms away, then push them back, then up and down. The strength should be about equal in both arms and in each direction. You can check their leg strength by having them lay flat and raise the lower legs while you resist the movement.

Step 8. Sensory Perception

Starting at the top of the body, check if they can feel the touch of your hand as you move downwards on each side while their eyes are closed. If they will allow you to do so, try to cover the entire body.

Step 9. Balance and Coordination

Be prepared to protect the diver from injury during this part of the neurological observation. Have them walk heel to toe along a straight line while looking straight ahead. Have them walk forward and backward for about three (3) metres (10 feet).

Make a note of whether the movements are smooth and if they are able to maintain their balance without having to look down or needing to hold on to a sturdy object.


Ask the diver to stand up with their feet together, eyes closed, and holding their arms straight out in front (with their palms facing upward).

They should be able to maintain a good balance if they're on a stable platform. You should be prepared to catch them if they start to fall.

Check their coordination by having them move an index finger back and forth quite quickly between their nose and your finger (held about half a metre from their face). They should still be able to do this when you move your finger to different positions.

Have them lie down - with eyes closed - get them to slide the heel of one foot down the shin of their other leg. It should be smooth and there should be no clumsiness or side-to-side jerky movements.

DAN Neurological Assessment: Special Considerations

Pro Tip: Any test that requires the diver to raise the head above the chest should not be performed in the field on a diver who has had neurological symptoms within thirty (30) minutes of surfacing from a dive.

DAN On-Site Neurological Assessment Course

This advanced-level program is for individuals who have already successfully completed DAN Oxygen First Aid for Diving Emergencies Certification (or have an equivalent qualification).

The three (3) hour course is designed to teach recreational divers how to execute a neurological exam for assisting a fellow diver in an emergency situation.

Primary Objectives of the Course

  • Refresh the knowledge of the Decompression Illness (DCI), Arterial Gas Embolism (AGE), and Decompression Sickness (DCS)
  • The Five Areas Evaluated as Part of an on-site neurology evaluation, including:
    • Mental Function
    • Cranial Nerves
    • Motor Function (Strength)
    • Sensory Function
    • Balance and Coordination
  • Take a dive history and past medical condition history
  • How to conduct the complete DAN On-Site Neurological Assessment

Participants also learn how to obtain essential information about a diver with a potential diving injury and what information should be relayed to emergency medical services (EMS).

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