Table 2.

Classification and Description of Pain Types and Associated Terminology.

Term	Definition of Pain
Pain	An unpleasant sensory and emotional experience associated with actual or potential tissue damage or described in terms of such damage.
Neuropathic Pain	Pain caused by a lesion or disease of the somatosensory system.
Central Neuropathic Pain	Neuropathic pain resulting from a lesion or disease of the central somatosensory nervous system.
Peripheral Neuropathic Pain	Neuropathic pain resulting from a lesion or disease of the peripheral somatosensory nervous system.
Nociceptive Pain	Pain that arises from actual or threatened damage to non-neural tissue and is due to the activation of nociceptors.
Nociplastic Pain	Pain that arises from altered nociception despite no clear evidence of actual or threatened tissue damage.
	Types of Pain Sensations:
Allodynia	Pain due to a stimulus that does not normally provoke pain.
Hyperalgesia	An increased response to a stimulus which is normally painful.
Hypoalgesia	Decreased sensitivity to painful stimuli.
Anesthesia dolorosa	Pain in an area or region which is anesthetic.
Dysesthesia	An unpleasant abnormal sensation, whether spontaneous or evoked.
Hyperesthesia	Increased sensitivity to stimulation, excluding the special senses.
Hyperpathia	A painful syndrome characterized by an abnormally painful reaction to a stimulus, especially a repetitive stimulus, as well as an increased threshold.
Hypoesthesia	Decreased sensitivity to stimulation, excluding the special senses.
Paresthesia	An abnormal sensation, whether spontaneous or evoked.
	Nerve-Related Terms:
Neuralgia	Pain in the distribution of a nerve or nerves.
Neuritis	Inflammation of a nerve or nerves.
Neuropathy	A disturbance of function or pathological change in a nerve.
Nociception	The neural process of encoding noxious stimuli.
Nociceptive Neuron	A neuron that is capable of detecting noxious stimuli.
Nociceptive Stimulus	A stimulus that is damaging or threatens damage to normal tissues.
Nociceptor	A receptor preferentially sensitive to a noxious stimulus or to a stimulus which would become noxious if prolonged.
Noxious Stimulus	A stimulus that is damaging to normal tissues.
	Pain Threshold and Tolerance:
Pain Threshold	The minimum intensity of a stimulus that is perceived as painful.
Pain Tolerance Level	The maximum level of pain which a subject is prepared to tolerate.
	Sensitization:
Sensitization	An increased response to stimulation.
Central Sensitization	Increased responsiveness of nociceptive neurons in the central nervous system to their normal or subthreshold afferent input.