The key difference between coma and vegetative state is that coma is a state in which a person appears to be asleep but cannot be awakened, while a vegetative state is a state in which a person appears to be awake but does not respond to the outside world properly.
Altered states of consciousness are changes in the normal consciousness or awareness of people due to internal or external factors. There are different types of altered consciousness states, such as coma, minimally conscious state, and vegetative state.
CONTENTS
1. Overview and Key Difference
2. What is a Coma
3. What is a Vegetative State
4. Similarities – Coma and Vegetative State
5. Coma vs. Vegetative State in Tabular Form
6. Summary – Coma vs. Vegetative State
What is a Coma?
A coma is an altered consciousness state in which a person appears to be asleep but cannot be awakened. When individuals are in a coma, they may have suffered damage to either the thalamus, the brainstem, or both hemispheres of the brain. In this condition, people are unresponsive to stimuli such as pain, sound, or touch, and they do not experience sleep-wake cycles as well. Moreover, in this condition, if the lower part of the brainstem has also been damaged, the patient even requires mechanical ventilation to breathe. Coma is usually caused by a severe brain injury such as a traumatic head injury, brainstem stroke, or brain hemorrhage. These brain injuries affect the surrounding tissue and brain structure. It can also be caused by severe hypothermia, drug overdose, drowning, and cardiac arrest. Moreover, the symptoms of this condition may include closed eyes, depressed brainstem reflexes, no responses to limb movement except for reflex movements, no response to painful stimuli except for reflex movements, and irregular breathing patterns.
Figure 01: Coma
Coma can be diagnosed through physical examinations, laboratory tests (blood tests), CT scans, MRIs, and electroencephalograms (EEG). Furthermore, treatment options for coma may include breathing assistance, medicines (glucose, or insulin, overdose-reversing medications (naloxone), anti-seizure medications, etc.) through a vein, and other supportive care.
What is a Vegetative State?
A vegetative state is when a person is awake but does not show any signs of awareness. A vegetative state occurs when the cerebrum is no longer functioning, but the hypothalamus and brain stem continue to function as usual. The signs and symptoms of this state may include opening the eyes, waking up and falling asleep at regular intervals, having basic reflexes, the ability to regulate their heartbeat and breathing without assistance, not showing any meaningful response such as following an object with the eyes or responding to voices in the outer environment, and showing no signs of experiencing emotions. A vegetative state is caused by severe brain damage due to a head injury or a disorder that deprives oxygen from the brain, such as cardiac or respiratory arrest.
A vegetative state is diagnosed through physical examination, EEG (electroencephalogram), CT scan, MRI, and PET scan. Furthermore, a vegetative state is treated by providing nutrition through a feeding tube, making sure the person is moving regularly in order to prevent pressure ulcers, gently exercising the joints, keeping the skin clean, managing the bowel and bladder movements, keeping the mouth clean, offering opportunities for meaningful activities and sensory stimulation.
What are the Similarities Between Coma and Vegetative State?
- Coma and vegetative state are two different states of altered consciousness.
- An untreated vegetative state can lead to coma.
- Both states can be caused by severe brain damage.
- Both states can be diagnosed through physical examination, CT scan, MRI, and electroencephalogram (EEG).
- They are treated through supportive care.
What is the Difference Between Coma and Vegetative State?
A coma is a state in which a person appears to be asleep but cannot be awakened, while a vegetative state is a state in which a person appears to be awake but does not respond to the outside world properly. Thus, this is the key difference between coma and vegetative state. Furthermore, in a coma, people have either damaged thalamus, the brainstem, or both hemispheres of the brain. On the other hand, in a vegetative state, only the cerebrum is damaged, hypothalamus and brain stem are functioning.
The infographic below presents the differences between coma and vegetative state in tabular form for side-by-side comparison.
Summary – Coma vs. Vegetative State
Normally, after a severe injury or illness of the brain, people may fall into a persistently unconscious state. This is also known as an altered consciousness state, which renders people unaware of themselves or their environment. Depending on the level of consciousness of people, they can be grouped into several altered consciousness states such as coma, minimally conscious state, vegetative state, or brain dead. Coma and vegetative state are two different states of altered consciousness. A coma is an altered consciousness state in which a person appears to be asleep but cannot be awakened, while a vegetative state is an altered consciousness state in which a person is awake but does not show any signs of awareness. So, this is the key difference between coma and vegetative state.
Reference:
1. “Coma.” Mayo Clinic.
2. Maiese, Kenneth. “Vegetative State – Brain, Spinal Cord, and Nerve Disorders.” MSD Manual Consumer Version.
Image Courtesy:
1. “Comaventilator” By Aaron Cohen – (CC BY-SA 3.0) via Commons Wikimedia