neuron degenerates or does not regenerate properly, then the neuron loses its function or may not function properly. Neuron trauma is not an isolated event and may cause degenerative changes in surrounding neurons. When one or more neurons lose their function or begin to malfunction, abnormal signals sent to the brain may be translated as painful signals. Diagnosis When assessing neuralgia to find the underlying mechanism, a history of the pain, description of pain, physical examination, and experimental examination are required. Pain is subjective to the patient, but pain assessment questionnaires, such as the McGill Pain Questionnaire can be useful for evaluation. Physical examinations usually involve testing responses to stimuli such as touch, temperature, and vibration. Neuralgia can be further classified by the type of stimuli that elicits a response: mechanical, thermal, or chemical. Response to the course of treatment is the final tool used to determine the mechanism of the pain. Additional tools may be used, predominantly in research settings including Laser Evoked Potentials and Quantitative Sensory testing. Laser evoked potentials Laser evoked potentials (LEPs) are measurements of cortical responses using lasers to selectively stimulate thermonociceptors in the skin. Lasers can emit a radiant-heat pulse stimulus to selectively activate A-delta and C free nerve endings. LEP abnormalities may be indicative of neuropathic pain, while a normal LEP is often more ambiguous. LEPs can assess damage to both central and peripheral nervous systems. Quantitative sensory testing Another method for testing the proper function of a nerve is Quantitative sensory testing (QST). QST relies on analysis of a patient's response to external stimuli of controlled intensity. A stimulus is applied to the skin of the nerve area being tested in ascending and descending orders of magnitude. Clinicians can quantify the mechanical sensitivity of the tactile stimulus using von Frey hairs or Semmes-Weinstein monofilaments (SWMFs). Also, weighted needles can be used to measure pin-prick sensation, and an electronic vibrameter is used to measure vibration sensitivity. Thermal stimuli are quantified by using a probe that operates on the Peltier principle. Treatment Treatment options include medicines and surgery. Neuralgia is more difficult to treat than other types of pain because it does not respond well to normal pain medications. Special medications have become more specific to neuralgia and typically fall under the category of membrane stabilizing drugs or antidepressants such as Cymbalta. The antiepileptic medication(AED) Lyrica (pregabalin) was developed specifically for neuralgia and other