A method and an apparatus for predicting and detecting epileptic seizure
onsets within a unified multiresolution probabilistic framework, enabling
a portion of the device to automatically deliver a progression of
multiple therapies, ranging from benign to aggressive as the
probabilities of seizure warrant. Based on novel computational
intelligence algorithms, a realistic posterior probability function
P(S.sub.T|x) representing the probability of one or more seizures
starting within the next T minutes, given observations x derived from
IEEG or other signals, is periodically synthesized for a plurality of
prediction time horizons. When coupled with optimally determined
thresholds for alarm or therapy activation, probabilities defined in this
manner provide anticipatory time-localization of events in a synergistic
logarithmic-like array of time resolutions, thus effectively
circumventing the performance vs. prediction-horizon tradeoff of
single-resolution systems. The longer and shorter prediction time scales
are made to correspond to benign and aggressive therapies respectively.
The imminence of seizure events serves to modulate the dosage and other
parameters of treatment during open-loop or feedback control of seizures
once activation is triggered. Fast seizure onset detection is unified
within the framework as a degenerate form of prediction at the shortest,
or even negative, time horizon. The device is required to learn in order
to find the probabilistic prediction and control strategies that will
increase the patient's quality of life over time. A quality-of-life index
(QOLI) is used as an overall guide in the optimization of
patient-specific signal features, the multitherapy activation decision
logic, and to document if patients are actually improving.