The term functional has almost replaced psychogenic in the neuromuscular literature for two reasons. It implies a disturbance of function, not structural damage; therefore, it defies laboratory testing such as MRIS, electromyography (EMG), and nerve conduction study (NCS). It is convenient to draw a parallel to the patients between migraine and brain tumors, as both cause headache, but brain MRI is negative in the former without minimizing the suffering of the patient. It is a “software” and not a “hardware” problem. It avoids irritating the patient by misunderstanding the word psychogenic which to many means “madness.”The cause of this functional impairment may fall into one of the following categories:• Conversion reaction: conversion of psychological stress to physical symptoms. This may include paralysis, hemisensory or distal sensory loss, or conversion spasms. It affects younger age groups.• Somatization: chronic multiple physical and cognitive symptoms due to chronic stress. It affects older age groups.• Factions disorder: induced real physical symptoms due to the need to be cared for, such as injecting oneself with insulin to produce hypoglycemia.• Hypochondriasis: overconcern about body functions such as suspicion of ALS due to the presence of rare fasciclutations that are normal during stress and after ingestion of a large amount of coffee. Medical students in particular are targets for this disorder.The following points are to be made on this topic. FNMD should be diagnosed by neuromuscular specialists who are trained to recognize actual syndrome whether typical or atypical. Presentations that fall out of the recognition pattern of a neuromuscular specialist, after the investigations are negative, they should be considered as FNMDs. Sometimes serial examinations are useful to confirm this suspicion. Psychatrists or psychologists are to be consulted to formulate a plan to discover the underlying stress and to treat any associated psychiatric disorder or psychological aberration. Most patients think that they are stressed due to the illness and they fail to connect the neuromuscular manifestations and the underlying stress. They offer shop around due to lack of satisfaction, especially those with somatization disorders. Some patients learn how to imitate certain conditions well, and they can deceive health care professionals. EMG and NCS are invaluable in revealing FNMD. A normal needle EMG of a weak muscles mostly indicates a central etiology (organic or functional). Normal sensory responses of a severely numb limb mean that a lesion is preganglionic (like roots avulsion, CISP, etc.) or the cause is central (a doral column lesion or functional). Management of FNMD is difficult, and many patients end up being chronic cases that wander into clinics and hospitals seeking solutions and exhausting the health care system with unnecessary expenses.It is time for these disorders to be studied in detail and be classified and have criteria set for their diagnosis so that they will not remain diagnosed only by exclusion. This chapter will describe some examples of these disorders. A video clip can tell the story better than many pages of writing. Improvement of digital cameras and electronic media has improved the diagnosis of these conditions, and it is advisable that patients record some of their symptoms when they happen. It is not uncommon for some Neuromuscular disorders (NMDs), such as myasthenia gravis (MG), small fiber neuropathy, and CISP, to be diagnosed as functional due to the lack of solid physical findings during the time of the examination. Therefore, a neuromuscular evaluation is important before these disorders are labeled as such. Some patients have genuine NMDs, but the majority of their symptoms are related to what Joseph Marsden called “sickness behavior.” A patient with carpal tunnel syndrome (CTS) may unconsciously develop numbness of the entire side of the body because he thinks that he may have a stroke.
Temperature-sensitive Recurrent, Reversible Auditory Neuropathy in Two Iranian Siblings
