17 - Seizures and epilepsy - CCMTA Medical Standards
Seizures, epilepsy and medical fitness to drive.
- 17.6.1 Provoked seizures caused by a structural brain abnormality
- 17.6.2 Provoked seizures with no structural brain abnormality
- 17.6.3 Alcohol-withdrawal seizures
- 17.6.4 Single unprovoked seizure – Non-commercial drivers
- 17.6.5 Single unprovoked seizure – Commercial drivers
- 17.6.6 Epilepsy – Non-commercial drivers
- 17.6.7 Epilepsy with seizures only while asleep or upon awakening – Non-commercial drivers
- 17.6.8 Epilepsy with simple partial seizures – Non-commercial drivers
- 17.6.9 Surgery for epilepsy – Non-commercial drivers
- 17.6.10 Surgery for epilepsy – Commercial drivers
- 17.6.11 Epilepsy with medication change – Non-commercial drivers
- 17.6.12 Epilepsy – Commercial drivers
- 17.6.13 Epilepsy with seizures only while asleep or upon awakening – Commercial drivers
- 17.6.14 Epilepsy with simple partial seizures – Commercial drivers
- 17.6.15 Epilepsy with medication change – Commercial drivers
17.1 About seizures and epilepsy
Seizures
A seizure is caused by a sudden electrical discharge in the brain. A seizure does not always mean that a person falls to the ground in convulsions. It can be manifested in various ways, including:
- Feelings of being absent
- Visual distortions
- Nausea
- Vertigo
- Tingling
- Twitching
- Shaking
- Rigidity of parts of the body or the entire body, or
- An alteration or loss of consciousness
Seizures may occur in people who do not have epilepsy. These non-epileptic seizures are often referred to as provoked seizures. Some are caused by transient factors with no structural brain abnormality such as:
- Fever
- Low blood sugar
- Electrolyte imbalance
- Head trauma
- Meningitis
- Simple fainting, and
- Alcohol or drug toxicity or withdrawal
Others are caused by conditions where there is a structural brain abnormality such as a:
- Tumour
- Stroke
- Aneurysm, or
- Hematoma
Provoked seizures are not epilepsy, and they resolve after the provoking factor has resolved or stabilized.
Sometimes people appear to have seizures, even though their brains show no seizure activity. This phenomenon is called a non-epileptic psychogenic seizure (NEPS), sometimes referred to as a pseudoseizure, and is psychological in origin. Some people with epilepsy have NEPS in addition to their epileptic seizures. Other people who have NEPS do not have epilepsy at all.
Epilepsy
Epilepsy refers to a condition characterized by recurrent (at least two) seizures, which do not have a transient provoking cause. The cause of the epileptic seizures may be known or unknown (idiopathic). About two-thirds of epilepsy in young adults is idiopathic, but more than half of epilepsy in those 65 and older has a known cause. Known causes of epilepsy include permanent structural brain abnormality such as scarring from:
- Stroke
- Prior surgery
- Head injury
- Infections
- Tumours
- Aneurysms, or
- Arteriovenous malformations.
Types of seizures
Seizures are divided into two main categories: partial (also called focal or local) seizures and generalized seizures. A partial seizure is a seizure that arises from an electrical discharge in one part of the brain. A generalized seizure is caused by discharges throughout the brain.
Partial seizures
There are three types of partial seizures:
- Simple partial seizures
- Complex partial seizures, and
- Partial seizures (simple or complex) that evolve into secondary generalized seizures (see below).
The difference between simple and complex seizures is that individuals experiencing simple partial seizures retain awareness during the seizure, whereas those experiencing complex partial seizures lose awareness during the seizure.
Symptoms of partial seizures depend on which part of the brain is affected. They may include one or more of the following:
- Head turning
- Eye movements
- Mouth movements
- Lip smacking
- Drooling
- Apparently purposeful movements
- Rhythmic muscle contractions in a part of the body
- Abnormal numbness
- Tingling and a crawling sensation over the skin
- Sensory disturbances such as smelling or hearing things that are not there, or
- Having a sudden flood of emotions.
Individuals who have partial seizures, especially complex partial seizures, may experience an aura, i.e. unusual sensations that warn of an impending seizure. An aura is actually a simple partial seizure. The aura symptoms an individual experiences and the progression of those symptoms tend to be similar every time.
Generalized seizures
Types of generalized seizures and their symptoms are listed in the table below.
Type of Generalized Seizure |
Symptoms |
Absence |
Brief loss of consciousness |
Myoclonic |
Sporadic (isolated), jerking movements |
Clonic |
Repetitive, jerking movements |
Tonic |
Muscle stiffness, rigidity |
Tonic-clonic or ‘grand mal’ |
Unconsciousness, convulsions, muscle rigidity |
Atonic |
Loss of muscle tone |
Most common seizures
The three most common types of seizures in adults are:
- Generalized tonic-clonic or grand mal seizures
- Complex partial seizures, and
- Simple partial seizures
Approximately one-third of all individuals with epilepsy have complex partial seizures, with the prevalence increasing to one-half in those with epilepsy who are 65 and older.
Recurrence of seizures
The estimated risk of a recurrence after an initial unprovoked seizure ranges from 23% to 71%, with the average risk of recurrence for adults being 43%. If the seizure is idiopathic (i.e. the cause is unknown) and the individual’s electroencephalogram (EEG) is normal, the risk of recurrence is reduced. Individuals who experience a partial seizure and have an abnormal EEG or other neurological abnormality, have an increased risk for seizure recurrence. A family history of epilepsy also increases the risk of recurrence.
Treatment for seizures and epilepsy
Seizure patterns in individuals with epilepsy may change over time, and seizures may eventually stop. Epilepsy is generally treated with anticonvulsant drugs (antiepileptics) and is sometimes treated with surgery to remove the source of epilepsy from the brain. Recent studies indicate that more than half of newly diagnosed individuals with epilepsy can achieve seizure control with antiepileptic drugs. Many of those who achieve seizure control are eventually able to stop taking antiepileptic drugs and remain seizure-free.
However, the relapse rate with drug withdrawal is at least 30% to 40%. For a further discussion of the impact of antiepileptics on driving, see Chapter 15, Drugs, Alcohol and Driving.
17.2 Prevalence
Research indicates that up to 9% of the general population will have at least one seizure. Epilepsy has an overall prevalence rate of 0.6% in Canada, with an estimated incidence of 15,500 new cases per year (2003). The table below shows the prevalence of epilepsy in Canada by age*.
(*Source: Data from Ontario Health Survey, Community Health Survey and National Population Health Survey (Wiebe S, Bellhouse D, Fallary C, Eliasziv M. Burden of epilepsy: the Ontario health survey. Can J Neurol Sci 1999;26:263-70).)
Age (years) |
Prevalence (%) |
Age (years) |
Prevalence (%) |
0 – 11 |
0.3 |
25 – 44 |
0.7 |
12 – 14 |
0.6 |
46 – 64 |
0.7 |
16 – 24 |
0.6 |
> 65 |
0.7 |
17.3 Seizures, epilepsy and adverse driving outcomes
Research indicates that, in general, individuals with epilepsy have an increased risk for adverse driving outcomes. Variability in the methodology and study results makes it difficult to determine the extent of the increased risk.
Studies of crash rates indicate that the following factors increase the risk of crash for those with epilepsy:
- Age – younger drivers have increased risk, particularly those under 25
- Marital status – unmarried drivers are at a greater risk than married drivers, and
- Treatment – those not receiving antiepileptic drug treatment are at greater risk than those receiving treatment.
17.4 Effect on functional ability to drive
Condition |
Type of driving impairment and assessment approach |
Primary functional ability affected |
Assessment tools |
Seizures Epilepsy |
Episodic impairment: Medical assessment – likelihood of impairment |
Variable – sudden impairment |
Medical assessments |
The primary consideration for drivers with epilepsy is the potential for a seizure causing a sudden impairment of cognitive, motor or sensory functions, or a loss of consciousness while driving.
17.5 Compensation
As seizures and epilepsy cause an episodic impairment of the functions necessary for driving, a driver cannot compensate.
17.6 Guideline for assessment
Rationale for all epilepsy and seizure standards
The general approach of the guideline for drivers with epilepsy or who experience seizures is that seizures must be controlled as a prerequisite to driving.
Most of the guidelines include a requirement for a seizure-free period. The purpose of this requirement for a provoked seizure is to establish the likelihood that the provoking factor has been successfully treated or stabilized. For an unprovoked seizure, the purpose is to allow time to assess the cause, and where epilepsy is diagnosed, to establish the likelihood that:
- A therapeutic drug level has been achieved and maintained
- The drug being used will prevent further seizures, and
- There are no side effects that may affect the driver’s ability to drive safely.
The guidelines identify exceptions to the requirement to remain seizure free for non- commercial drivers who have epilepsy and who have only simple partial seizures, or seizures that only occur while they are asleep or immediately upon awakening.
17.6.1 Provoked seizures caused by a structural brain abnormality
This standard applies to drivers who have experienced provoked seizures caused by a structural brain abnormality such as:
- A brain tumour
- Stroke
- Subdural hematoma, or
- Aneurysm
National Standard |
All drivers eligible for a licence if
|
BC Guidelines |
If further information is required, RoadSafetyBC may request
|
Conditions for maintaining licence |
None |
Reassessment |
|
Information from health care providers |
|
Rationale |
The primary consideration for drivers who experience seizures is the potential for a seizure causing a sudden impairment of cognitive, motor or sensory functions, or a loss of consciousness while driving. The purpose of a seizure-free period. requirement for a provoked seizure is to establish the likelihood that the provoking factor has been successfully treated or stabilized |
17.6.2 Provoked seizure with no structural brain abnormality
This standard applies to drivers who have experienced provoked seizures caused by a:
- Toxic illness
- Adverse drug or alcohol reaction, and substance use disorder* is not diagnosed (*Note if substance use disorder is diagnosed, then 17.6.3 would apply)
- Trauma, or
- Other cause that is not associated with a structural brain abnormality (for example psycho genec non epileptic (PNES) .
National Standard |
All drivers eligible for a licence if:
|
BC Guidelines |
If further information is required, RoadSafetyBC may request:
|
Conditions for maintaining licence |
None |
Reassessment |
No re-assessment, other than routine commercial or age-related re-assessment, is required |
Information from health care providers |
|
Rationale |
The primary consideration for drivers who experience seizures is the potential for a seizure causing a sudden impairment of cognitive, motor or sensory functions, or a loss of consciousness while driving. The general approach of the guidelines for drivers who experience seizures is that seizures must be controlled as a prerequisite to driving and/or the provoking factor has stabilized, resolved, or has been corrected |
17.6.3 Alcohol withdrawal seizures
National Standard |
All drivers eligible for a licence if:
|
BC Guidelines |
If further information is required, RoadSafetyBC may request an assessment from a neurologist, a registered psychologist or an addictions specialist or a physician who is familiar with client’s past medical history or has access to client’s past clinical /medical records. For drivers without a diagnosis of alcohol use disorder, RoadSafetyBC may find individuals fit to drive if they meet the National Standard for 17.6.2. For drivers with a diagnosis of alcohol use disorder, RoadSafetyBC may find individuals fit to drive if they meet the above National Standard. |
Conditions for maintaining licence |
RoadSafetyBC will impose the following conditions on an individual who is found fit to drive:
|
Reassessment |
|
Information from health care providers |
|
Rationale |
The primary consideration for drivers who experience seizures is the potential for a seizure causing a sudden impairment of cognitive, motor or sensory functions, or a loss of consciousness while driving. The purpose of a seizure-free period. requirement for a provoked seizure is to establish the likelihood that the provoking factor has been successfully treated or stabilized |
17.6.4 Single unprovoked seizure – Non-commercial drivers
National Standard |
Non-commercial drivers eligible for a licence if:
|
BC Guidelines |
|
Conditions for maintaining licence |
None |
Reassessment |
|
Information from health care providers |
|
Rationale |
The primary consideration for drivers who experience seizures is the potential for a seizure causing a sudden impairment of cognitive, motor or sensory functions, or a loss of consciousness while driving.The purpose of a seizure-free period requirement for an unprovoked seizure is to allow time to assess the cause and establish seizures are controlled as a prerequisite to driving |
17.6.5 Single unprovoked seizure – Commercial drivers
National Standard |
Commercial drivers eligible for a licence if:
|
BC Guidelines |
If further information is required, RoadSafetyBC may request
|
Conditions for maintaining licence |
None |
Reassessment |
RoadSafetyBC will re-assess in one year. If no further seizures are reported at that time, RoadSafetyBC will re-assess in accordance with routine commercial re-assessment |
Information from health care providers |
|
Rationale |
The primary consideration for drivers who experience seizures is the potential for a seizure causing a sudden impairment of cognitive, motor or sensory functions, or a loss of consciousness while driving.The purpose of a seizure-free period requirement for an unprovoked seizure is to allow time to assess the cause and establish seizures are controlled as a prerequisite to driving |
17.6.6 Epilepsy – Non-commercial drivers
This standard applies to non-commercial drivers who have been diagnosed with epilepsy, with the following exceptions:
- If the epileptic seizures only occur while the driver is asleep, or immediately after awakening, standard 17.6.7 applies.
- If the driver only experiences simple partial seizures, standard 17.6.8 applies.
- If the driver has had surgery for epilepsy, standard 17.6.9 applies.
- If the driver has changed effective medication, standard 17.6.11 applies.
National Standard |
Non-commercial drivers eligible for a licence if:
|
BC Guidelines |
If further information is required, RoadSafetyBC may request:
|
Conditions for maintaining licence |
RoadSafetyBC will impose the following conditions on an individual who is found fit to drive:
|
Reassessment |
|
Information from health care providers |
|
Rationale |
The general approach of the guidelines for drivers with epilepsy or who experience seizures is that seizures must be controlled as a prerequisite to driving. The purpose of a seizure-free period requirement where epilepsy is diagnosed is to establish the likelihood that a therapeutic drug level has been achieved and maintained; the drug being used will prevent further seizures, and there are no side effects that may affect the individual’s ability to drive safely |
17.6.7 Epilepsy with seizures only while asleep or upon awakening – Non-commercial drivers
National Standard |
Non-commercial driver eligible for a licence if:
|
BC Guidelines |
If further information is required, RoadSafetyBC may request:
|
Conditions for maintaining licence |
RoadSafetyBC will impose the following conditions on an individual who is found fit to drive:
|
Reassessment |
No re-assessment, other than routine age-related re-assessment, is required |
Information from health care providers |
|
Rationale |
The purpose of a seizure-free period requirement for drivers with epilepsy with seizures only while asleep or upon awakening is to establish seizures are controlled or seizure pattern has been consistent for a prescribed time as a prerequisite to driving |
17.6.8 Epilepsy with simple partial seizures – Non-commercial drivers
This standard applies to non-commercial drivers with epilepsy who only experience simple partial seizures (no impairment in level of consciousness), the symptoms of which do not impair their functional ability to drive.
National Standard |
Non-commercial drivers eligible for a licence if:
|
BC Guidelines |
If further information is required, RoadSafetyBC may request:
|
Conditions for maintaining licence |
RoadSafetyBC will impose the following conditions on an individual who is found fit to drive:
|
Reassessment |
No re-assessment is required, other than routine age-related re- assessment |
Information from health care providers |
|
Rationale |
The purpose of a seizure-free period requirement for drivers with epilepsy with simple partial seizures is to establish seizures are controlled or seizure pattern has been consistent for a prescribed time as a prerequisite to driving |
17.6.9 Surgery for epilepsy – Non-commercial drivers
National Standard |
Non-commercial drivers eligible for a licence if:
|
BC Guidelines |
If further information is required, RoadSafetyBC may request:
|
Conditions for maintaining licence |
RoadSafetyBC will impose the following conditions on an individual who is found fit to drive:
|
Reassessment |
|
Information from health care providers |
|
Rationale |
The purpose of a seizure-free period requirement for drivers with epilepsy who had a surgery is to establish seizures are controlled as a prerequisite to driving |
17.6.10 Surgery for Epilepsy – Commercial drivers
National Standard |
Commercial drivers eligible for a licence if:
|
BC Guidelines |
If further information is required, RoadSafetyBC may request:
|
Conditions for maintaining licence |
RoadSafetyBC will impose the following conditions on an individual who is found fit to drive:
|
Restrictions |
RoadSafetyBC will place the following restriction on an individual’s licence who meet the medical standard for commercial drivers with epilepsy:
|
Reassessment |
|
Information from health care providers |
|
Rationale |
The purpose of a seizure-free period requirement for drivers with epilepsy who had a surgery is to establish seizures are controlled as a prerequisite to driving. |
17.6.11 Epilepsy with medication change – Non-commercial drivers
This standard applies to non-commercial drivers with epilepsy who undergo a prescribed change to, or withdrawal of, an effective antiepileptic medication. This standard only applies where the driver’s treatment was effective (i.e. their epilepsy was controlled) prior to the change to, or withdrawal from, medication. This means they should not have had a seizure for at least six months prior to the change or withdrawal of medication. If their treatment prior to the change was not effective, then guideline 17.6.6 applies.
National Standard |
|
BC Guidelines |
If further information is required, RoadSafetyBC may request:
|
Conditions for maintaining licence |
|
Reassessment |
|
Information from health care providers |
|
Rationale |
The general approach of the guidelines for drivers with epilepsy or with medication change for epilepsy, or who experience seizures is that seizures must be controlled as a prerequisite to driving |
17.6.12 Epilepsy – Commercial drivers
This standard applies to commercial drivers, who have been diagnosed with epilepsy, except:
- Whose seizures only occur while they are asleep or immediately after awakening, and (17.6.13)
- Who have only simple partial seizures (no impairment in level of consciousness), the symptoms of which do not impair their functional ability to drive (17.6.14).
See guideline 17.6.15 for commercial drivers who meet this standard and then change medication.
National Standard |
Commercial drivers eligible for a licence if:
|
BC Guidelines |
|
Conditions for maintaining licence |
RoadSafetyBC will impose the following conditions on an individual who is found fit to drive:
|
Restrictions |
RoadSafetyBC will place the following restriction on an individual’s licence who meet the medical standard for commercial drivers with epilepsy
|
Reassessment |
RoadSafetyBC will re-assess in accordance with the schedule for routine commercial re-assessment |
Information from health care providers |
|
Rationale |
The general approach of the guidelines for drivers with epilepsy or who experience seizures is that seizures must be controlled as a prerequisite to driving. The purpose of a seizure-free period requirement where epilepsy is diagnosed is to establish the likelihood that a therapeutic drug level has been achieved and maintained; the drug being used will prevent further seizures, and there are no side effects that may affect the individual’s ability to drive safely |
17.6.13 Epilepsy with seizures only while asleep or upon awakening – Commercial drivers
National Standard |
Commercial drivers eligible for a licence if:
|
BC Guidelines |
If further information is required, RoadSafetyBC may request:
|
Conditions for maintaining licence |
RoadSafetyBC will impose the following conditions on an individual who is found fit to drive:
|
Restrictions |
RoadSafetyBC will place the following restriction on an individual’s licence who meet the medical standard for commercial drivers with epilepsy
|
Reassessment |
RoadSafetyBC will re-assess in accordance with the schedule for routine commercial re-assessment |
Information from health care providers |
|
Rationale |
The primary consideration for drivers with epilepsy is the potential for a seizure causing a sudden impairment of cognitive, motor or sensory functions, or a loss of consciousness while driving. The general approach of the guidelines for drivers with epilepsy who experience seizures while asleep or upon awakening is to establish seizures are controlled or seizure pattern has been consistent for a prescribed time as a prerequisite to driving |
17.6.14 Epilepsy with simple partial seizures – Commercial drivers
National Standard |
Commercial drivers eligible for a licence if:
|
BC Guidelines |
If further information is required, RoadSafetyBC may request:
|
Conditions for maintaining licence |
RoadSafetyBC will impose the following conditions on an individual who is found fit to drive:
|
Restrictions |
RoadSafetyBC will place the following restriction on an individual’s licence who meet the medical standard for commercial drivers with epilepsy
|
Reassessment |
RoadSafetyBC will re-assess in accordance with the schedule for routine commercial re-assessment |
Information from health care providers |
|
Rationale |
The purpose of a seizure-free period requirement for drivers with epilepsy with simple partial seizures is to establish seizures are controlled or seizure pattern has been consistent for a prescribed time as a prerequisite to driving |
17.6.15 Epilepsy with medication change – Commercial drivers
This standard applies to commercial drivers with epilepsy who undergo a prescribed change to, or withdrawal of, an effective antiepileptic medication. This standard only applies where the driver’s treatment was effective (i.e. their epilepsy was controlled) prior to the change to, or withdrawal from, medication. This means they must first meet guideline 17.6.12 before this standard will apply.
National Standard |
Commercial drivers eligible for a licence if:
|
BC Guidelines |
If further information is required, RoadSafetyBC may request:
|
Conditions for maintaining licence |
RoadSafetyBC will impose the following conditions on an individual who is found fit to drive:
|
Restrictions |
RoadSafetyBC will place the following restriction on an individual’s licence who meet the medical standard for commercial drivers with epilepsy
|
Reassessment |
RoadSafetyBC will re-assess in accordance with the schedule for routine commercial re-assessment |
Information from health care providers |
|
Rationale |
The purpose of a seizure-free period. requirement for drivers with epilepsy with medication change is to establish seizures are controlled as a prerequisite to driving |