A seizure occurs when there is abnormal electrical activity in the brain that results in an involuntary change in body movement or function, sensation, awareness, or behavior. Seizures can look very different depending on the type and where they occur in the brain. An important question for many people with epilepsy is whether they remain conscious and aware during a seizure.
What is consciousness?
Consciousness refers to being awake, aware, and able to perceive and respond to your environment. It involves:
– Wakefulness – being awake rather than asleep.
– Awareness – having knowledge of internal and external stimuli.
– Responsiveness – being able to react to stimuli through speech, movement or physiological changes.
Levels of consciousness can range from being fully awake and alert, to being drowsy or confused, to being unresponsive as in coma.
Can you be conscious during a seizure?
Yes, it is possible to remain conscious and aware during certain types of seizures, although consciousness is impaired to some degree.
The level of consciousness retained depends on what part of the brain the seizure occurs in:
– Frontal lobe seizures often cause minor impairments in awareness or responsiveness. People may appear dazed, wandering and purposeless.
– Temporal lobe seizures can cause hallucinations, dissociative experiences or dream-like states with some awareness retained.
– Occipital lobe seizures may affect vision but leave other senses intact.
– Parietal lobe seizures can disrupt attention, speech and senses but people remain partially responsive.
So in these types of focal (partial) seizures, people retain some awareness and recollection of the event.
However, in more severe focal seizures consciousness becomes increasingly impaired. And in generalized seizures that involve both sides of the brain, there is usually complete loss of consciousness and memory of the event.
What does loss of consciousness in seizures involve?
When consciousness is impaired or lost during a seizure, some or all of these aspects may be affected:
– Disrupted wakefulness – the person may appear asleep or unresponsive.
– Impaired awareness – they are unable to engage with their surroundings and lack awareness of self or events.
– Reduced responsiveness – they cannot respond purposefully to stimuli and follow commands.
– Amnesia – no memory of the seizure afterwards.
– Automatisms – repetitive, involuntary movements like lip smacking, chewing, swallowing or random movements. These can occur with altered awareness.
So seizures involving loss of consciousness may involve collapsing, convulsions, staring spells and periods of unresponsiveness. The person often has no memory afterwards of what happened.
What are some features of conscious seizures?
Seizures where consciousness is retained can be harder to recognize but may involve:
– A sudden feeling of detachment, dissociation or dream-like state
– Experiencing distortions – time may appear slowed down, surroundings may seem unfamiliar.
– Hallucinations or illusions – seeing, hearing, smelling or tasting things that are not real.
– Automatisms while retaining awareness – repetitive automatic movements while awake.
– Impaired attention – difficulty concentrating or responding.
– Aphasia – difficulty understanding or producing speech.
– Preserved memory – ability to recall aspects of the seizure afterwards.
What are some specific types of conscious seizures?
Some examples of seizures types where consciousness can be preserved include:
Simple partial seizures – involve just one area of the brain and may cause twitching or sensory disturbances while retaining awareness.
Complex partial seizures – originate in one part of the brain but consciousness is impaired to some degree. People experience automatisms and altered awareness.
Absence seizures – involve brief lapses in consciousness of 5-10 seconds. Awareness is impaired but people quickly recover.
Auras – focal onset seizures that may precede larger seizures. Auras involve sensory changes like stomach sensations, mood changes, visual disturbances or dissociation.
So in these types of seizures, the person retains some level of consciousness, though it is disrupted to varying degrees.
How is consciousness affected in convulsive seizures?
In contrast, consciousness is typically completely lost in:
– Tonic-clonic seizures – Features initial muscle stiffening followed by convulsions. Violent muscle contractions cause loss of consciousness.
– Clonic seizures – Involves repeated or rhythmic jerking movements of the arms and legs. Consciousness is impaired.
– Tonic seizures – Cause stiffening or rigidity of the muscles. People often lose awareness and collapse.
– Atonic seizures – Lead to loss of muscle control, causing a person to suddenly collapse or drop their head. Lead to brief loss of consciousness.
So in these generalized seizure types featuring convulsions, people usually have no awareness of what is happening and cannot remember the seizure afterwards.
Why might someone remain conscious during a seizure?
Reasons someone may retain some consciousness during a seizure include:
– The seizure originates and is limited to one area of the brain, rather than spreading widely.
– It is a smaller seizure that does not spread.
– It is a focal aware seizure previously called a simple partial seizure.
– Areas controlling wakefulness and awareness are unaffected.
– Memory functions remain intact, allowing recall.
So localized, smaller seizures or those intentionally affecting regions controlling consciousness are more likely to involve retained awareness.
Do seizures really cause loss of consciousness?
There has been debate around whether seizures really cause a loss of consciousness or rather just an impairment in forming and recalling memories.
Some argue that generalized tonic-clonic seizures don’t lead to true unconsciousness, as subtle physical, autonomic and brain activity responses can still occur.
However, most experts maintain seizures involve a period where normal wakeful consciousness is impaired or absent to some degree. Tests of awareness and responsiveness during seizures confirm this disruption.
Could consciousness remain when it appears lost?
Sometimes there are reports of unresponsiveness not matching the person’s subjective experience, raising questions over how consciousness correlates with observable behavior.
Reasons consciousness may appear lost from the outside but not the inside during seizures include:
– Paralysis – Muscles required for movement may be temporarily paralyzed by the seizure, even if the person is awake internally.
– Dissociation – A sense of detachment from the environment or body can occur, with retained internal awareness.
– Impaired memory – Consciousness may be intact but the seizure disrupts the ability to form memories.
– Confusion – Disorientation, cognitive deficits and impaired decision making may inhibit intentional reactions.
– Altered perceptions – Unusual sensations, time distortion and hallucinations may mask intact consciousness.
So while appearing unresponsive outwardly, subtle inner awareness could theoretically remain. But most evidence indicates actual loss of normal alertness.
Testing awareness during seizures
Various methods are used in research or clinical settings to attempt to assess consciousness during seizures. These include:
– Observing for purposeful behavioral responses to stimuli like noise, touch or pain.
– Monitoring brainwaves for signs of localized activity versus global disruption.
– Using verbal commands or questions to test comprehension, memory and responsiveness.
– Assessing automatic non-purposeful behavior versus intentional, conscious reactions.
– Comparing first and second-hand accounts to cross-check experiences.
– Questioning the person after the seizure about recall of events.
But it remains difficult to externally measure internal awareness accurately, especially when subjective recall is impaired.
Are there risks if you remain conscious?
If consciousness is preserved during a seizure, some particular risks include:
– Greater risk of injury if automatisms occur while walking or standing
– Potential embarrassment due to unusual behaviors during complex partial seizures
– Aura or simple partial seizures may progress to impaired consciousness
– Memories of seizures afterwards can be disturbing if consciousness was intact
– Dissociative states can be frightening if they occur while conscious
So retaining awareness carries additional difficulties in some circumstances.
Can you avoid losing consciousness?
It is not usually possibly to voluntarily control whether consciousness is impaired during a seizure. The loss of awareness results from involuntary electrical disturbances in the brain.
But some measures that may reduce loss of consciousness include:
– Taking anti-seizure medication regularly to minimize seizures
– Avoiding known triggers like lack of sleep, alcohol, stress, hyperventilation
– Using treatments like vagus nerve stimulation, ketogenic diet, or responsive neurostimulation
– Having surgery to remove focal areas of seizure activity, if possible
– Having another person guide you to safely lie down at seizure onset
– Maintaining seizures within certain brain regions through biofeedback training
While you cannot choose to remain aware, overall seizure control can minimize impairment of consciousness.
Conclusion
In summary, it is possible to retain consciousness during certain seizure types, depending on where they occur in the brain and how widely activity spreads. But many seizures do impair awareness and responsiveness to some degree or cause complete loss of consciousness temporarily. While appearing unconscious outwardly, internal subtle awareness may theoretically remain in some cases. However, true alert wakeful consciousness is disrupted in most observable seizure events. Managing seizures through medication, lifestyle changes, devices or surgery can help reduce loss of awareness.
References
| Reference | Key points on consciousness during seizures |
|---|---|
| Fisher et al (2017). Consciousness and epilepsy: why are patients with absence seizures absent? | – Consciousness is disrupted in generalized absence seizures with impaired awareness. |
| Johanson et al (2003). A systematic review of the literature on consciousness in temporal lobe epilepsy. | – Consciousness can be preserved in simple partial and complex partial seizures but is impaired in dyscognitive focal seizures. |
| Englot and Chang (2014). Seizure localization: can we image conscious and unconscious brain activity? | – Tests during seizures reveal widespread cortical dysfunction with impaired consciousness in convulsive seizures. |
| Cavanna et al (2017). Revisiting consciousness in temporal lobe epilepsy. | – Temporal lobe seizures can involve dissociation with subjective detachment from environment while retaining awareness. |
| Yang et al (2011). Localization of consciousness during partial seizures. | – Partial seizures disrupt consciousness when they impair function in regions like frontal lobes, thalamus and upper brainstem. |