Phaser-induced peripheral neuropathy (PIPN), colloquially known as stun-shock or nerve-burn, is a condition of the humanoid nervous system--particularly the peripheral nerves, though there may be central nervous system involvement as well--induced by the cumulative effects of multiple phaser hits, which may consist of excessive use of the stun setting or a much fewer number of high-powered hits. As such, PIPN is one of the most iconic soldier's maladies of the spacefaring age, much as trench-foot was to the soldiers of the first two Earth World Wars.
PIPN has been observed in humanoid species as dissimilar as Xindi-Primates and Cardassians, and presumably many others.
As with a number of complex neurological conditions, modern technology often remains at a loss to completely cure afflicted individuals; therefore patients who experience onset of major symptoms are likely to experience them for the rest of their lives.
Those at highest risk for permanent phaser-induced peripheral neuropathy are individuals serving in the military and in other occupations with a high risk of combat. The level of risk of irreversible symptoms increases with the number of times that an individual has been shot. Survivors of particularly high-intensity beams may have a higher risk factor increase resulting from a single incident than someone exposed to many stuns, though this is not an inviolable rule.
Signs and symptoms
Clinical presentation and severity of symptoms vary greatly from case to case depending on species as well as the nature and location of the actual phased-energy contact wound, since some species are more likely to survive high-intensity phaser hits than others and may therefore have a higher incidence of PIPN. However, all cases are united by the immediate and at least partly irreversible loss of neural function following being shot.
Typically patients present with tremors, cramps, and myalgia (pain of neurological origin). They may also notice stiffness in affected areas as well as involuntary fasciculations (muscle twitches). Reaction time and general coordination are also likely to be affected. In some, severity of symptoms may increase in times of heightened emotion, whereas meditation may temporarily mitigate--though not entirely eliminate--the symptoms.
In the most serious cases, PIPN, though classically a condition of the peripheral nervous system, may also be comorbid with central nervous system disruptions. The beam impact itself may trigger seizures at onset; when severe enough, the patient may enter into status epilepticus, a condition of continuous seizures that if not treated in time, can be lethal. While in most cases cognitive function remains undisturbed, in the most severe instances untreatable cognitive loss may result.
Treatment and outlook
In less severe cases, particularly those resulting from first exposures, the neurological damage resulting from a direct phaser hit can be treated to a point where the damage is only apparent in medical scans, though the process may take time and require physical therapy. Individuals who have experienced this temporary precursor to PIPN are therefore advised to take great pains to avoid circumstances where they could be injured again.
Full-blown PIPN, however, is typically irreversible; therefore patient care typically consists of symptom minimization and occupational therapy to ease the impact on his or her daily living activities. The extent and nature of the disability must be assessed and managed on a case-by-case basis.
Patients often find themselves unable to manage tasks requiring the fine use of the hands such as writing and anything much more than basic computer console use. The pain of myalgic episodes, however, is one of the greatest complaints PIPN sufferers have, and must often be treated with highly potent painkillers. Not all patients, however, are willing to accept such treatment despite the pain due to the side effects. For such patients, meditation and other mental control exercises present a viable--though most often less effective--alternative.
Due to the already serious neurological damage, people who have manifested symptoms of PIPN are at a high risk of death from even a low-intensity phaser shot and in most cases take great care to avoid situations where this is likely. One notable individual to defy this risk, however, is Gul Tayben Berat, who petitioned for the right to remain in service of the Cardassian Guard following onset of major symptoms.
Related military policies
In peacetime, Starfleet procedure is to medically evaluate all personnel who are shot in or out of the line of duty. When neurological scans reveal an increased risk for PIPN onset, the CMO will generally restrict that individual to shipboard duty until the risk factor decreases to acceptable levels. During the Dominion War, however, this became much less feasible, resulting in a sharp increase of documented PIPN cases.
Starfleet generally works with crew members who have PIPN to reassign them into areas where they may continue productive (and advancing) careers in positions without the physical demands and dangers of a shipboard posting. Some have remained in shipboard postings, though this is an extremely uncommon decision that is always reviewed on a case-by-case basis.
Standard Cardassian Guard procedure is to immediately discharge all affected individuals from service, as is true with almost all disabling conditions. Very few Cardassians are permitted to remain in service with any form of disability, and an appeal to Central Command for reinstatement is often viewed as insubordination and may have deadly results.
Gul Berat, however, successfully appealed his discharge orders and retains command of the Sherouk, making him the highest-ranked of only six individuals to serve shipboard with any sort of disability. (The type and extent of the disabilities the other five have is unknown.) In this case, Legate Tekeny Ghemor assigned Berat a new first officer whose job it is, in addition to the normal tasks of the XO, to assist Berat in shipboard tasks he lacks the physical capability to do. Berat rarely participates in away missions, and when he does, his first officer accompanies him.
His disability, however, has had no impact on his ship's combat performance; he and the Sherouk are notable for the daring rescue of the beleaguered Romac during the Septimus Massacre as well as for participation in the anti-Dominion rebel group, the Thirteenth Order. Berat himself was also responsible for eliminating the Vorta on board his ship, with the aid of his crewmates--placing his life at great risk to accomplish his plan.
-  Visit this page to view a general symptomology of peripheral neuropathy and related conditions with other causes.