Differential Changes in Peripheraland Central Components of the Brain Stem Auditory Evoked Potentials during the Neonatal Period Interm Infants after Perinatal Hypoxia-Ischemia

Serum biomarkers of hypoxic-ischemic brain injury

Brain injury is a multifaceted condition arising from nonspecific damage to nervous tissue. The resulting cognitive developmental impairments reverberate through patients' lives, affecting their families, and even the broader economic landscape. The significance of early brain injury detection lies in its potential to stave off severe consequences and enhance the effectiveness of tailored therapeutic interventions. While established methods like neuroimaging and neurophysiology serve as valuable diagnostic tools, their demanding nature restricts their accessibility, particularly in scenarios such as small hospitals, nocturnal or weekend shifts, and cases involving unstable patients. Hence, there is a pressing need for more accessible and efficient diagnostic avenues. Among the spectrum of brain injuries, hypoxic-ischemic encephalopathy stands out as a predominant affliction in the pediatric population. Diagnosing brain injuries in newborns presents challenges due to the subjective nature of assessments like Apgar scores and the inherent uncertainty in neurological examinations. In this context, methods like magnetic resonance and ultrasound hold recommendations for more accurate diagnosis. Recognizing the potential of serum biomarkers derived from blood samples, this paper underscores their promise as a more expedient and resource-efficient means of assessing brain injuries. The review compiles current insights into serum biomarkers, drawing from experiments conducted on animal models as well as human brain pathologies. The authors aim to elucidate specific characteristics, temporal profiles, and the available corpus of experimental and clinical data for serum biomarkers specific to brain injuries. These include neuron-specific enolase (NSE), ubiquitin carboxy-terminal hydrolase L1 (UCH-L1), S100 calcium-binding protein beta (S100B), glial fibrillary acidic protein (GFAP), and high-mobility-group-protein-box-1 (HMGB1). This comprehensive endeavor contributes to advancing the understanding of brain injury diagnostics and potential avenues for therapeutic intervention.

Neurophysiological recordings improve the accuracy of the evaluation of the outcome in perinatal hypoxic ischemic encephalopathy

OBJECTIVES

Our objective was to evaluate the potential additional value of electroencephalogram (EEG) and evoked potentials in neonates with hypoxic-ischemic encephalopathy to predict their disability at 1 and 2 years old.

METHODS

30 full-term infants after perinatal asphyxia who underwent therapeutic hypothermia were evaluated at 1 year and 2 years for disability using International Classification of Functioning, Disability and Health classification. Scores for EEG, sensory evoked potentials and brainstem auditory evoked potentials were evaluated after withdrawal of therapeutic hypothermia that lasted 72 h. A regression approach was investigated to build models allowing to distinguish neonates according to their disability at 1 and 2 years. Two models were built, the first by considering the clinical data and EEG before and after therapeutic hypothermia and the second by incorporating evoked potentials recording.

RESULTS

Adding EEG and evoked potentials data after rewarming improved dramatically the accuracy of the model considering outcome at 1 and 2 years.

INTERPRETATION

We propose to record systematically EEG and evoked potentials following rewarming to predict the outcome of neonates with hypoxic ischemic encephalopathy. Combination of altered evoked potentials with no improvement of EEG after rewarming appeared to be a robust criterion for a poor outcome.

Postnatal functional status of the brainstem auditory pathway in term infants after perinatal hypoxia-ischemia

OBJECTIVES

To examine postnatal changes in the impaired brainstem auditory pathway in term infants after perinatal hypoxia-ischemia (HI).

METHODS

Brainstem auditory evoked response (BAER) was studied at 2-4 months of age in term infants who suffered perinatal HI. The BAER data obtained at various click rates in these infants were compared with those in age-matched normal term controls to detect any abnormalities.

RESULTS

The infants after HI showed a slight elevation in BAER threshold. Four (9.8%) infants had threshold elevation. At 21/s clicks, there was a slight decrease in wave I latency, and a slight increase in wave III and V latencies. However, the I-V and I-III intervals in these infants were significantly increased (p < .05 and .05), whereas III-V interval was slightly increased. At higher click rates of 51 and 91/s, all BAER variables showed similar changes, with only small variations. An abnormal increase in the I-V and/or I-III intervals was seen in 4 (9.8%) infants, who were not associated with BAER threshold elevation.

CONCLUSIONS

At 2-4 months of age, around 20% of the infants after perinatal HI showed a moderate degree of either peripheral or central impairment of the brainstem auditor pathway. Monitoring postnatal changes could provide valuable information for postnatal care of infants after perinatal HI.

The potential role of auditory evoked potentials to assess prognosis in comatose survivors from cardiac arrest

AIM

Few data are available on the use of brainstem auditory evoked potentials (BAEPs) in combination with other electrophysiological tools to assess prognosis of comatose survivors from cardiac arrest (CA).

METHODS

Retrospective analysis of data from all adult patients (>18years of age) admitted to our Dept of Intensive Care after CA over a 6-year period who were comatose (Glasgow Coma Scale <9) on admission, had been treated with targeted temperature management and had BAEP testing. We collected variables related to CA, as well as electroencephalography (EEG) findings, N20 somatosensory evoked potentials, and the presence of I, III and/or V waves on BAEP testing. Outcome was assessed at 3 months using the Cerebral Performance Categories (3-5=poor outcome).

RESULTS

We studied 65 patients; 48 (74%) had a poor neurological outcome. BAEP assessment was performed day 3 [3,4] after the CA. At least one of the three waves was absent bilaterally in 34 patients (52%); of these patients, 29 (85%) had a poor neurological outcome (sensitivity 60%, specificity 71%, positive predictive value [PPV] 85% and negative predictive value [NPV] 39%). Three patients (5%) had bilateral absence of all three waves, all of whom had a poor neurological outcome.

CONCLUSIONS

In this series of patients after CA, at least one of the BAEP waves was absent bilaterally in half the survivors; however, their use for prediction of poor neurological outcome remains limited.