Ocular motor and motor exam of a comatose patient

[Alex Turcios]

Hi,
I am having trouble understanding ocularmotor, motor examination, and pupillary eye reflex testing in a comatose patient. Isnet a coma defined as unconscious with no periods of wakefulness? And isent preservation of cranial nerves part of vegetative state? If once is in a coma, wont they just fail all test given. And if they are able to demonstrate eye movements or light reflex, doesn’t that make them a vegetative state?

[Chrissy Durrough Lugge]

Hi Alex,
Correct – a coma is a state of unarousable unconsciousness with no periods of wakefulness or eye opening in response to stimulation. A vegetative state (or unresponsive wakefulness syndrome) is marked by periods of wakefulness but no signs of awareness of oneself or the surroundings.

Coma is caused by disordered arousal (level of consciousness) whereas vegetative state is caused by absence of awareness (content of consciousness.

The Coma Recovery Scale-Revised (or CRS-R or JFK Coma Recovery Scale) is a standardized neurobehavioral assessment measure designed for use in individuals with disorders of consciousness. The scale is intended to be used to establish diagnosis, monitor behavioral recovery, predict outcomes, and assess treatment effectiveness. It consists of 6 subscales to assess brainstem, subcortical, and cortically mediated behaviors. The scale is intended to be administered repeatedly over time to monitor change.

The scale details how to assess each item (including auditory, visual, motor, oromotor, communication, and arousal functions). For instance, motor responses range from appropriate functional use of objects to no response to noxious stimuli. You can see the details for the assessment here: https://www.tbims.org/combi/crs/CRS%20Syllabus.pdf

Once a person with a disorder of consciousness demonstrates presence of sleep-wake cycles but lacks evidence of awareness of self and environment, they are considered to be in a vegetative state. When they have discernable and reproducible evidence of awareness of self or environment (simple command following, yes/no responses, intelligible verbalization, purposeful behavior), they are considered to be in a minimally conscious state.

[Alex Turcios]

Interesting,,,

I think part of my confusion comes from Batemans article highlighting neuroanatomical bases of coma. This article gives explanation and instruction on how to perform various neurological assessment for this population. What I am confused about is, how is it possible to ask a patient to open their eyes and perform movements if they are in a coma?

[Chrissy Durrough Lugge]

We want to ask the patients to perform certain tasks as part of our assessment, though we wouldn’t expect the patient to follow our commands if they are truly in a coma. Visual tasks are important because they can help us identify if a person has locked-in syndrome rather than coma.

I think reviewing the Coma Recovery Scale will help you because it details the follow-up assessments if someone cannot follow commands (i.e., manually open eyes and present visual threat to assess visual startle as the visual function exam).

[Alex Turcios]

Interesting, thank you!

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