Todd’s Paresis and Postictal Neurological Deficits

Postictal neurology

After a seizure, some people develop a temporary focal neurological deficit such as weakness, numbness, language difficulty or visual disturbance. These deficits can look exactly like stroke, so a new focal deficit must be assessed urgently rather than assumed to be “just postictal”.

Key point: Todd’s paresis is a recognised postictal phenomenon, but stroke can also present with a seizure. New one-sided weakness, aphasia, visual loss or another focal neurological deficit should therefore be treated as possible stroke until clinically assessed.

What is Todd’s paresis?

Todd’s paresis, also called Todd’s paralysis, is a temporary focal weakness that appears after a seizure. It usually affects one side of the body or one limb, but the pattern depends on which brain networks were involved in the seizure.

The term comes from the classic observation of postictal weakness, but the broader concept of postictal focal neurological dysfunction is more accurate because deficits can affect more than movement.

Postictal deficits are not limited to weakness

Possible postictal focal deficits include:

one-sided weakness or heaviness
reduced coordination
numbness or altered sensation
speech or language impairment
visual-field loss or other visual disturbance
neglect
gaze deviation
temporary problems with reading, writing or calculation

A 2026 systematic review of postictal signs included paresis, language deficits, visual impairment, memory disturbance and autonomic features among recognised postictal phenomena.

Why does it happen?

The exact mechanism is not fully settled. Proposed mechanisms include temporary postictal inhibition, altered cortical excitability and changes in local cerebral blood flow after the seizure.

Postictal perfusion can be reduced in the affected brain region, which is one reason imaging can sometimes resemble early ischaemia.

How long can Todd’s paresis last?

Duration is variable. Symptoms may resolve within minutes or hours, but published reports describe deficits lasting much longer and occasionally persisting for days.

A long duration does not prove stroke, but neither does a known history of Todd’s paresis safely exclude it.

Why it is such an important stroke mimic

Seizures and postictal states are among the most important stroke mimics. Acute weakness, aphasia, facial droop or visual loss after a seizure can look indistinguishable from an ischaemic stroke at first assessment.

The difficulty runs both ways: an acute stroke can itself trigger a seizure at onset. That means “there was a seizure first” is not enough to rule stroke out.

New focal symptoms should be treated as possible stroke

NICE recommends using FAST outside hospital for sudden-onset neurological symptoms and rapidly establishing the diagnosis in suspected stroke or TIA.

New one-sided weakness, facial droop or speech/language disturbance warrants urgent stroke assessment even in someone with established epilepsy.

FAST still matters after a seizure

FAST stands for:

Face: new facial weakness or droop
Arms: new weakness in one arm
Speech: new speech or language difficulty
Time: seek emergency help immediately

A seizure history should not delay emergency action if FAST symptoms are new or atypical.

Postictal aphasia

Language can remain impaired after a seizure. A person may be unable to understand speech, name objects, retrieve words or produce meaningful language.

Postictal aphasia can have lateralising value in focal epilepsy, but a new language deficit is also a classic stroke presentation and must be assessed accordingly.

Postictal sensory deficits

Some people experience temporary numbness, reduced sensation or altered body perception after seizures. These symptoms may follow sensory seizure activity or occur as a negative postictal phenomenon.

Sudden unilateral numbness should still be assessed as possible stroke or TIA, in line with NICE guidance.

Visual deficits

Temporary postictal visual-field loss or other visual disturbance can occur after seizures involving visual networks.

A new visual-field deficit, particularly when accompanied by weakness, speech change or severe headache, requires urgent assessment because stroke and other neurological causes can present similarly.

Neglect and higher cortical deficits

Postictal deficits can involve higher cortical functions. A person may ignore one side of space, have difficulty carrying out learned actions, or show transient problems with reading, writing or calculation.

These features can be clinically useful but are not safe to self-diagnose as postictal without proper assessment.

Gaze deviation

Eye or head deviation can persist briefly after some focal seizures. The direction and timing may provide lateralising information to clinicians, but it must be interpreted alongside the seizure sequence and other findings.

Why imaging may be needed

CT, CT angiography and MRI may be used when stroke is suspected. Neuroimaging is essential when clinicians need to distinguish a postictal deficit from acute cerebral ischaemia or haemorrhage.

Perfusion imaging can be complicated because postictal brain regions may show hypoperfusion that resembles ischaemia. Clinical evolution, vascular imaging, diffusion MRI and EEG may all contribute to the final diagnosis.

EEG can help, but it does not solve everything

EEG may show focal slowing or epileptiform activity after a seizure, but these findings are not always specific enough to distinguish postictal dysfunction from acute stroke on their own.

Persistent focal deficits therefore need a combined clinical, imaging and neurophysiological assessment.

Nonconvulsive seizures can also produce negative symptoms

Not every focal deficit after suspected seizure activity is truly postictal. Ongoing focal or nonconvulsive seizure activity can sometimes cause weakness, aphasia, neglect or visual symptoms.

This is another reason prolonged deficits may require EEG rather than simply waiting for them to resolve.

Todd’s paresis can follow focal or bilateral convulsive seizures

Postictal weakness can follow focal motor seizures, focal-to-bilateral tonic-clonic seizures and other seizures involving motor cortex or connected networks.

The weakness may affect the same body region involved during the seizure, but patterns are not always that simple.

A known history helps — but does not remove risk

If a person repeatedly develops the same brief postictal weakness after the same seizure type, that history is useful to clinicians.

However, a new, more severe, longer-lasting or different focal deficit still needs urgent assessment because stroke, bleeding or another neurological problem can occur in someone who also has epilepsy.

What carers and witnesses should record

Useful details include:

which side or body part was weak
whether the face was affected
whether sensation changed
whether language or vision changed
when the deficit began
whether it followed a witnessed seizure
how long it lasted
whether it matched the person’s previous postictal pattern
whether recovery was complete

This history is valuable, but it should not delay calling emergency services for a new acute focal deficit.

Put a known pattern into the care plan

If someone has a clinically recognised, recurring postictal deficit, their epilepsy care plan can describe the usual pattern and expected duration.

The plan should also state clearly what would count as atypical and when emergency assessment is required.

Read more: Epilepsy Care Plans →

When to call 999

Call emergency services for a new or concerning focal neurological deficit, especially:

new one-sided weakness
new facial droop
new aphasia or severe speech disturbance
new visual-field loss
new neglect or severe imbalance
deficits lasting much longer than the person’s established pattern
deficits after head injury
severe headache, reduced consciousness or other signs of possible stroke or bleeding

The central point

Todd’s paresis is real, but it is not a safe explanation to assume. A postictal focal deficit can mimic stroke closely, and stroke can itself trigger a seizure.

The safest rule is simple: if the weakness, language problem, visual loss or other focal deficit is new, different or unusually prolonged, treat it as possible stroke until assessed.

Where next?

Postictal Recovery →
Language and Speech During and After Seizures →
Diagnosis and Tests →
Injuries After Seizures →
Back to Understanding Epilepsy →

Sources

Medical note: Sudden focal neurological symptoms require urgent assessment. A history of epilepsy or previous Todd’s paresis does not safely exclude stroke.

Evidence checked: September 2026.