Spasms are brief, involuntary muscle contractions or jerks, and are typically associated with specific types of epilepsy, notably infantile spasms or West's Syndrome. These spasms are typically associated with an abnormal background of EEG activity known as hypsarrhythmia, which involves high-amplitude, disorganized brain waves. However, spasms can also occur in other epileptic syndromes, such as Lennox-Gastaut syndrome.

What Are Spasms?

Spasms refer to a series of sudden, brief muscle contractions or jerking movements, often involving the arms, neck, or torso. They are particularly common in infants and are a key feature of West's Syndrome, though they can also occur in other epilepsy syndromes. These spasms are usually associated with severe cognitive and developmental delays, as well as abnormal EEG findings.

Clinical Features of Spasms

The clinical presentation of spasms can include:

  • Head Drop: A sudden, brief dropping of the head, usually occurring due to the contraction of neck muscles. This is a classic feature of infantile spasms.
  • Bilateral Tonic Arm Raise and Extension: During a spasm, both arms may rise and extend in a tonic posture, often associated with a sudden contraction of the muscles.
  • Myogenic Artifact: Because spasms involve intense muscle contractions, there is often significant myogenic artifact seen on the EEG, which can sometimes obscure the underlying brain activity.

Electrographic Characteristics of Spasms

Electrographically, spasms are recognized by their characteristic patterns:

  • High-Amplitude Slow Waves: Spasms typically appear as brief, diffuse high-amplitude slow waves on the EEG, often lasting for a very short duration.
  • Overriding Fast Activity: These slow waves are frequently accompanied by a burst of fast activity, which may appear as polyspikes or other fast discharges. This combination creates a complex, disorganized pattern.
  • Hypsarrhythmia: In cases of West's Syndrome, spasms occur alongside hypsarrhythmia. This refers to a chaotic, highly disorganized background activity on the EEG, with multifocal spikes and slow waves, often highly irregular and not following any typical rhythmic pattern.

Associated Conditions

While spasms are most commonly associated with West's Syndrome, they can also be seen in other epilepsy syndromes, including:

  • Lennox-Gastaut Syndrome: A severe form of epilepsy that begins in early childhood and is characterized by multiple types of seizures, including spasms. This syndrome is often accompanied by cognitive impairment and developmental delays.
  • Other Epileptic Syndromes: Spasms may also occur in other forms of epilepsy, such as myoclonic epilepsy or other generalized epileptic syndromes, although this is less common.

Diagnosis and Testing

The diagnosis of spasms typically involves a combination of:

  • Clinical Observation: Noticing the typical jerking movements, such as head drops and tonic arm posturing, is key in identifying spasms.
  • EEG Monitoring: The EEG is crucial for identifying the characteristic patterns of spasms, such as the high-amplitude slow waves and fast activity. In cases of West's Syndrome, hypsarrhythmia will also be observed.
  • Developmental Assessments: Since spasms are often associated with developmental delays, a thorough assessment of cognitive and motor development is important for understanding the extent of the impact on the child.

Management of Spasms

The treatment of spasms focuses on controlling the seizures and addressing the underlying epilepsy syndrome:

  • Corticosteroids: Medications such as prednisone or ACTH (adrenocorticotropic hormone) are often the first line of treatment in infantile spasms, particularly for West's Syndrome.
  • Vigabatrin: Another key treatment for infantile spasms, especially in cases with associated tuberous sclerosis. Vigabatrin has been shown to be effective in reducing the frequency of spasms in some children.
  • Ketogenic Diet: A ketogenic diet, which is high in fats and low in carbohydrates, may be used to help control seizures in children with epilepsy syndromes that are resistant to medication.
  • Other Anti-Seizure Medications: Depending on the syndrome and the severity of the spasms, other anti-seizure medications may be considered, including valproic acid or topiramate.

Prognosis

The prognosis for children with spasms depends heavily on the underlying cause and the timeliness of treatment. Early intervention is important for improving outcomes, especially in cases of West's Syndrome. However, long-term cognitive and developmental delays are common, and some children may continue to experience seizures despite treatment.

In some cases, spasms may resolve over time, but ongoing seizure control and developmental support are often required. If left untreated, spasms can lead to more severe developmental and neurological impairments.