Abstract
Background: The value of amplitude integrated EEG (aEEG) for early diagnosis of perinatal brain injury in fullterm asphyxia has been extensively studied. However, most studies have focused on the global aspect of the tracing: continuous normal voltage, discontinuous intermittent low voltage, burst suppression, very low voltage or inactive flat tracing. These scoring systems are based on qualitative assessments. We were interested in the measurement of some quantitative more objective discrete parameters reflecting amplitude and frequency variations.
Aims: To evaluate changes of discrete electrophysiological parameters, obtained through the analysis of the aEEG in fullterm asphyxiated infants. Methods: Between May 2004 and April 2005, 12 term infants with perinatal asphyxia were included. Asphyxia was defined by an Apgar score <6 at 5 minutes, or metabolic acidosis with cord pH<7 or base excess <-10. EEG electrodes were placed bilaterally at the C3, C4, P3, and P4 placement according to the modified international 10–20 system (Hydrospot® neonatal electrodes, Physiometrix Inc, North Billerica, MA) and applied with minimal skin preparation within 6–10h of birth. The aEEGs were recorded continuously during 24–72 hours on the REBRM3 (research BRM, Brainz Instruments Ltd, Auckland, NZ). The EEG amplitude, intensity and spectral edge measurements were averaged and stored to disk at 1-minute intervals. The averaged signals were analysed off-line using customized software (Chart analyser, Brainz Instruments). The distribution of the median parameters, analysed separately for each hemispheric recording, were compared in the infants with or without brain injury evidenced by advanced MRI. Functional outcome was measured at 43 wks by a specialized assessment scale of infant behavior (APIB).
Results: 6 infants were excluded due to technical problems in the recordings. Among the 6 remaining patients, 2 exhibited basal ganglia lesions on MRI and 4 had a normal brain MRI. The minimal value of aEEG (aEEG min) and the spectral edge frequency in the bursts (SEFb) were analysed during the first hour of the recording, then 12 hours and 18 hours after the beginning of the recording. The results were compared between the group of patients with brain lesions and the group of patients without lesions. There was a statistically significant difference in the measurement of aEEG min (1.52mV1+/−0.7 vs 7.4mV1 +/−3 p= 0.004), and SEFb (5.03 Hz+/−2.5 vs 12.2 Hz +/−7 p=0.001) during the first hour of the recording comparing infants with MRI evidence of basalganglia lesions to infants with no lesions. The measurements at 12 hours and 18 hours did not differ significantly. Behavioral assessment (APIB) showed significantly less mature scores in the attention-interaction capacity and in the autonomic reactivity in the group of patients with lesions (p<0.05).
Conclusions: These preliminary results obtained on a small group of infants suggest that monitoring with aEEG and measurement of aEEG min and SEFb in the first 6–10 hrs of life after perinatal asphyxia may enable to detect brain injury to the basalganglia in term newborns. Whether these results are specific to basal ganglia lesions needs to be studied more extensively. Nevertheless these findings stress the importance of early electrophysiological monitoring after asphyxia, in order to offer better guidance to the primary caregivers.
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Menache, C., Sizonenko, S., Borradori-Tolsa, C. et al. 237 Detection of Basal Ganglia Injury by Early use of Amplitude Integrated EEG in Neonatal Asphyxia. Pediatr Res 58, 395 (2005). https://doi.org/10.1203/00006450-200508000-00266
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DOI: https://doi.org/10.1203/00006450-200508000-00266