| spike and wave complex | A generalised, synchronous pattern seen on the electroencephalogram, consisting of a sharply contoured fast wave followed by a slow wave; particularly found in patients with generalised epilepsies. Spike and wave complexes are often characterised by their frequency, e.g., s low spike and wave, fast spike and wave. (05 Mar 2000) |
|---|---|
| square wave stimuli | Electrical stimulation in which the intensity of the current is brought suddenly to a given level and maintained at that level until it suddenly is cut off; this type of stimulus is particularly useful in obtaining a strength-duration curve. (05 Mar 2000) |
| delta wave | A premature upstroke of the QRS complex due to an atrial ventricular bypass tract as in WPW syndrome. Synonym: delta rhythm. (05 Mar 2000) |
| S wave | A negative (downward) deflection of the QRS complex following an R w; successive downward deflections within the same QRS complex are labelled S', S'', etc. (05 Mar 2000) |
| dicrotic wave | The second rise in the tracing of a dicrotic pulse. Synonym: recoil wave. (05 Mar 2000) |
| drift wave | <radiobiology> Oscillations in a magnetically-confined plasma arising in the presence of density gradients (such as at the plasma's surface). These resemble the waves that propagate at the interface of two fluids with different density in a gravitational field. (09 Oct 1997) |
| D wave | A positive or negative deflection in the electroretinogram occurring when a light stimulus is removed (off-response). (05 Mar 2000) |
| quarter-wave plate | <microscopy> A compensator giving a retardation of about 130 nm, and a phase shift of 1/4 ~, thus constituting a device used with a polarizer and analyser designed to produce circularly polarized light. (05 Aug 1998) |
| Q wave | The initial deflection of the QRS complex when such deflection is negative (downward). (05 Mar 2000) |
| overflow wave | The descending wave of the sphygmogram from the apex to the first anacrotic break. (05 Mar 2000) |
| theta wave | Brain waves in the electroencephalogram which have a frequency of 4 to 7 per second. They occur mainly in children but also in adults during periods of emotional stress. (12 Dec 1998) |
| tidal wave | The wave between the percussion wave and the dicrotic wave in the downward limb of the arterial pulse tracing. (05 Mar 2000) |
| electrocardiographic wave | <cardiology, physiology> A deflection of special shape and extent in the electrocardiogram representing the electric activity of a portion of the heart muscle. (05 Mar 2000) |
| electrohydraulic shock wave lithotripsy | Destruction of calculi (urinary tract or other) by fragmentation using shock waves sent transcutaneously. (05 Mar 2000) |
| electromagnetic wave | <physics> A wave of electric and magnetic fields that can move through space. Particles which make up the waves are called photons. (09 Oct 1997) |