Serial electroencephalographic findings in patients with MELAS

Area of Science:

• Neurology
• Genetics
• Neurophysiology

Background:

• Mitochondrial myopathy, encephalopathy, lactic acidosis, and strokelike episodes (MELAS) is a maternally inherited disorder.
• A common point mutation at mitochondrial DNA nucleotide position 3243 is associated with MELAS and MELA syndromes.
• Understanding the electroencephalographic (EEG) patterns in MELAS is crucial for diagnosis and management.

Observation:

• EEG data from six MELAS patients and two MELA relatives with the 3243 mitochondrial DNA mutation were analyzed.
• Electroencephalograms were categorized based on their temporal relationship to strokelike episodes: pre-episode, acute (0-5 days), subacute (6 days-1 month), and chronic (>1 month).
• Focal high-voltage delta waves with polyspikes (FHDPS) were identified as ictal EEG patterns during acute stages.

Findings:

• In the acute stage following strokelike episodes, 10 out of 11 EEGs (9 episodes in 4 patients) showed FHDPS.
• Ictal events associated with FHDPS included focal clonic/myoclonic seizures and migrainous headaches.
• Focal spikes, sharp waves, and 14- and 6-Hz positive bursts were common in subacute and chronic stages.

Implications:

• FHDPS are a reliable and accurate EEG indicator for identifying strokelike episodes in MELAS patients.
• This EEG characteristic can aid in the early diagnosis and monitoring of neurological manifestations in MELAS.
• Further research into EEG patterns may improve understanding of MELAS pathophysiology and treatment strategies.