Delayed-onset dystonia due to perinatal asphyxia: a prospective study.

The objective of this work was to establish the existence and incidence of possible delayed-onset dystonia in a cohort of infants with diagnosed perinatal asphyxial hypoxic-ischemic encephalopathy (HIE). This prospective study comprised 103 survivors of perinatal asphyxial HIE, who were regularly followed and neurologically examined in the course of 7 to 13 years after birth (median 10 years). Neurological outcome at the end of the follow-up period was normal in 87 (84.5%) patients, while in 7 (6.8%) only mild neurological signs were detected (behavioral disturbances in 3, clumsiness in 2, and hypotonia in 1 patient). Severe cerebral palsy was diagnosed in nine patients (8.7%). Only one patient was diagnosed with possible delayed-onset segmental dystonia. At the age of 4 years he developed cervical dystonia with spread to one arm in the course of 1.5 years (segmental dystonia) and then stabilized. Other known causes of dystonia, including a DYT1 mutation, were excluded. Our preliminary data suggest that over the course of at least 7 years after birth, approximately 1% of infants who survived perinatal asphyxial HIE would develop delayed-onset dystonia.