Baxter P - Given that hypoxic-ischaemic insults occurring during or after birth can cause both acute and long-term neurological impairment, the author conducted this investigation to evaluate the impact of duration of the insult. Following the onset of persistent bradycardia in 125 term infants, abnormal results occurred in two by 10 minutes, 12 out of 47 delivered between 11 and 20 minutes, and 55 out of 65 delivered after 20 minutes. Findings revealed that there was little correlation with severity before 20 minutes, while most were severely impaired after 20 minutes. Limited data on neuroimaging indicate that damage limited to the basal ganglia and thalamus that begin to occur after 10 minutes, Rolandic damage associated after 15 minutes, and other cortical involvement after 20 minutes. Associated damage to white matter may occur after any duration. No data were provided for other damage patterns.