difference threshold

threshold

(thresh'(h)old?)

1. The point at which a psychological or physiological effect begins to be produced.

2. A measure of the sensitivity of an organ or function that is obtained by finding the lowest value of the appropriate stimulus that will give the response.

absolute threshold

The lowest amount or intensity of a stimulus that will give rise to a sensation or a response.

acoustic reflex threshold

The decibel level that provokes reflex contraction of the stapedius muscle. Tests that measure the triggering of the acoustic stapedius reflex are used to determine the presence of sensorineural hearing loss.

anaerobic threshold

The point at which increased carbon dioxide production and minute ventilation result from increased levels of lactic acid during exercise.

auditory threshold

The minimum audible sound perceived.

threshold of consciousness

In psychoanalysis, the point at which a stimulus is just barely perceived.

difference threshold

Just noticeable difference.

differential threshold

The lowest limit at which two stimuli can be differentiated from each other.

erythema threshold

The stage of ultraviolet skin injury in which erythema of the skin due to radiation begins.

ketone threshold

The level of ketone in the blood above which ketone bodies appear in the urine.

ketosis threshold

The lower limit at which ketone bodies, on their accumulation in the blood, are excreted by the kidney. At that point, ketone bodies are being produced faster by the liver than the body can oxidize them.

pain threshold

The minimum level of sensory stimulation that a person will perceive as being unpleasant, noxious, or intolerable.

pressure pain threshold

Abbreviation: PPT

The applied mass per area (kg/cm²) that will elicit a complaint of pain in subjects with painful conditions, e.g., fibromyalgia, temperomandibular joint dysfunction, or vulvodynia.

renal threshold

The concentration at which a substance in the blood normally not excreted by the kidney begins to appear in the urine. The renal threshold for glucose is 160 to 180 mg/dl.

seizure threshold

The level of neurological stimulation capable of precipitating a seizure.

sensory threshold

The minimal stimulus for any sensory receptor that will give rise to a sensation.

speech detection threshold

Abbreviation: SDT

The lowest level of sound intensity in decibels at which a person identifies a spoken word 50% of the time.

spondee threshold

In audiometry, the intensity at which speech is recognized as a meaningful symbol. This is tested by presenting, through an audiometer, two-syllable words in which each symbol is accented equally.

See: audiometry

viability threshold

The body weight or gestational age of an infant below which the ability to survive is doubtful.

difference threshold

in psychophysics, the smallest difference between two sensory inputs that can be detected. Also known as difference limen, discrimination threshold or just noticeable difference (jnd). See also absolute threshold.