Sporadic hyperekplexia due to self-limiting brainstem encephalopathy.

Area of Science:

• Neurology
• Movement Disorders
• Neuroscience

Background:

• Hyperekplexia is a rare neurological disorder characterized by an exaggerated startle reflex.
• It is distinguished from normal startle responses by a lower threshold, increased intensity, and resistance to habituation.
• Acquired forms often involve brainstem pathologies like encephalitis, infarcts, or compression.

Observation:

• This case report details a rare presentation of hyperekplexia.
• A key unusual feature was the occurrence of vocalization in response to startling stimuli.
• This startle-induced vocalization is not typically described in classical hyperekplexia.

Findings:

• The patient exhibited a pathologically exaggerated response to unexpected stimuli.
• Vocalization was a consistent and reproducible feature triggered by startling events.
• This suggests a broader clinical phenotype for hyperekplexia than previously documented.

Implications:

• Physicians should consider hyperekplexia in the differential diagnosis of exaggerated startle responses.
• The case underscores that hyperekplexia can present with atypical features, including vocalization.
• This expands the understanding of hyperekplexia's clinical manifestations and diagnostic considerations.