Monitoring Neurological Injury by qEEG - Quantitative EEG Analysis Methods and Clinical Applications - page 188

logical recovery as measured by NDS in animals treated with hypothermia. IQ also
predicts the 72-hour functional outcomes as early as 4 hours after CA.
The qEEG methodology presented here has the potential for early prognostica-
tion after resuscitation. Early correlation of NDS and IQ at 4 hours may provide an
opportune time for intervention or injury stratification. The strong correlation at 4
hours likely reflects the great variability between rats destined for good or poor out-
comes during this period [9]. These early hours after ROSC are characterized by
increasing frequency and complexity of bursts with a concomitant decrease in the
duration of EEG suppression. Animals that proceed more quickly to a continuous
EEG pattern have higher IQ values and better functional outcomes. The strong cor-
relation between the 72-hour IQ and final NDS likely reflects the reemergence of
EEG reactivity during this period in the group with good outcomes, whereas those
with poor outcomes tend to have nonreactive patterns and lower IQ values.

Our research also shows that the earlier administration of therapeutic hypother-
mia after CA not only leads to better functional outcome compared to conventional
hypothermia administration, but allows for reduction of treatment duration by half
(6 hours versus 12 hours). We also showed that the effect of therapeutic hypother-
mia on brain recovery was detected by the qEEG measure. Our experiments lend
further support to the theory that cooling should begin as soon as possible after
ROSC. Hypothermia may have a greater impact during the early period of recovery,
and injured neurons that are immediately treated may have a better chance of
recovering.
One of the major goals of our group is to develop experimental approaches that
can easily be translated clinically. The development of a noninvasive strategy to
track the course of recovery early after resuscitation from CA has a number of
readily translatable functions in humans. EEG technology is readily available in
most hospitals and is familiar to staff, rather than being restricted to tertiary aca-
demic centers. Entropy analysis as exemplified by IQ simplifies interpretation of
EEGs by translating complicated and subjective waveform analysis into an objective
measure that can be displayed in real time, allowing physicians to monitor the
response to potential neuroprotective strategies.

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References

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