A stimulation apparatus includes a stimulation lead (102), a multiplexer
(114), a stimulation signal generator (116), and a signal detector (120).
The stimulation lead (102) includes a plurality of stimulation electrodes
(112) disposed in an array about a distal portion of the lead body (110).
The arrangement of the electrodes (112) facilitates the controlled
steering of stimulating electrical field (118) in three dimensions. Four
dimensional field steering may also be provided.