A patient controls the delivery of therapy through volitional inputs that
are detected by a biosignal within the brain. The volitional patient
input may be directed towards performing a specific physical or mental
activity, such as moving a muscle or performing a mathematical
calculation. In one embodiment, a biosignal detection module monitors an
electroencephalogram (EEG) signal from within the brain of the patient
and determines whether the EEG signal includes the biosignal. In one
embodiment, the biosignal detection module analyzes one or more frequency
components of the EEG signal. In this manner, the patient may adjust
therapy delivery by providing a volitional input that is detected by
brain signals, wherein the volitional input may not require the
interaction with another device, thereby eliminating the need for an
external programmer to adjust therapy delivery. Example therapies include
electrical stimulation, drug delivery, and delivery of sensory cues.