An occurrence of Todd's paralysis indicates that a seizure has occurred. The prognosis for the patient depends upon the effects of the seizure, not the occurrence of the paralysis.

The cause of Todd's paresis been attributed to the affected cortex being ‘exhausted’ or silenced due to increased inhibition, but these conjectures are not supported. It has been observed that the impairments that follow seizures are similar to those that follow strokes, where for a period of time blood flow to certain areas of the brain is restricted and these areas are starved of oxygen.

Onset is between 3 and 15 years of age with a mean of around 8. Both sexes are equally affected. The disorder accounts for about 2–7% of benign childhood focal seizures.

The prognosis of ICOE-G is unclear, although available data indicate that remission occurs in 50–60% of patients within 2–4 years of onset. Seizures show a dramatically good response to carbamazepine in more than 90% of patients. However, 40–50% of patients may continue to have visual seizures and infrequent secondarily generalized convulsions, particularly if they have not been appropriately treated with antiepileptic drugs.

Postoperative residual curarization (PORC) is a residual paresis after emergence from general anesthesia with neuromuscular-blocking drugs.

The incidence of anesthesia awareness is higher and has more serious sequelae when muscle relaxants or neuromuscular-blocking drugs are used. This is because without relaxant the patient will move and the anesthesiologist will deepen the anesthesia.

One study has indicated this phenomenon occurs in about 1 or 2 per 1000 patients or 0.13%. There is conflicting data however as another study suggested it is a rare phenomenon, with an incidence of 0.0068% after review of their data from a patient population of 211,842 patients.

Post operative interview by an anesthetist is common practice to elucidate if awareness occurred in the case. If awareness is reported a case review is immediately performed to identify machine, medication, or operator error.

Anaphia, also known as tactile anesthesia, is a medical symptom in which there is a total or partial absence of the sense of touch.

Anaphia is a common symptom of spinal cord injury and neuropathy.

Awareness occurs when patients have anesthesia that is inadequate to keep them unconscious during an operation. The incidence of this anesthesia complication is variable and seems to affect 0.2% to 0.4% of patients according to the surgical setting carried out. This variation reflects the surgical setting as well as the physiological state of the patient. Thus, the incidence is 0.2% in general surgery, about 0.4% during caesarean section, between 1 and 2% during cardiac surgery and between 10% and 40% for anesthesia of the traumatized. The majority of these do not feel pain although around one third did, in a range of experience from a sore throat due to the endotracheal tube, to traumatic pain at the incision site. The incidence is halved in the absence of neuro-muscular blockade. In this situation, the patient may feel the pain or pressure of surgery, hear conversation, experience air hunger, or have difficulty breathing. The patient may be unable to communicate any distress because they have been given a muscle relaxant; without this, they can move and the anesthesiologists are alerted and provide more anesthetic drugs to render the patient unconscious again. If anesthesia awareness does occur, about 42% feel the pain of the operation, 94% experience panic or anxiety, and 70% experience lasting symptoms which may be psychological and may be physical or neurological. The quoted incidences are controversial as many cases of "awareness" are open to interpretation. These usually involve feeling severe pain, clear recall of the conversations of the operating room staff or suffocation. Some patients undergo sedation for smaller procedures such as biopsies and colonoscopies and are told they will be asleep, although in fact they are getting a sedation that may allow some level of awareness as opposed to a general anesthetic.

In some cases post traumatic stress disorder (PTSD) may arise after intraoperative awareness, causing the patient to require counseling for an extended period. Sometimes neurological and brain injuries caused during the operation are wrongly diagnosed and described as PTSD.

Although the theory is controversial, there is a link between febrile seizures (seizures coinciding with episodes of fever in young children) and subsequent temporal lobe epilepsy, at least epidemiologically.

Temporal lobe epilepsy (TLE) is a chronic disorder of the nervous system characterized by recurrent, unprovoked focal seizures that originate in the temporal lobe of the brain and last about one or two minutes. TLE is the most common form of epilepsy with focal seizures. A focal seizure in the temporal lobe may spread to other areas in the brain when it may become a "focal to bilateral seizure".

TLE is usually diagnosed in childhood or adolescence. TLE is diagnosed by taking a medical history, blood tests, and brain imaging. It can have a number of causes such as head injury, stroke, brain infections, structural lesions in the brain, or brain tumors, or it can be of "unknown onset". The first line of treatment is through anticonvulsants. Surgery may be an option, especially when there is an observable abnormality in the brain. Another treatment option is electrical stimulation of the brain through an implanted device called the vagus nerve stimulator (VNS).

Focal seizures (also called partial seizures and localized seizures) are seizures which affect initially only one hemisphere of the brain. The brain is divided into two hemispheres, each consisting of four lobes – the frontal, temporal, parietal and occipital lobes. A focal seizure is generated in and affects just one part of the brain – a whole hemisphere or part of a lobe. Symptoms will vary according to where the seizure occurs. In the frontal lobe symptoms may include a wave-like sensation in the head; in the temporal lobe, a feeling of déjà vu; in the parietal lobe, a numbness or tingling; and in the occipital lobe, visual disturbance or hallucination.

POCD is common after cardiac surgery, and recent studies have now verified that POCD also exists after major non-cardiac surgery, although at a lower incidence. The risk of POCD increases with age, and the type of surgery is also important because there is a very low incidence associated with minor surgery. POCD is common in adult patients of all ages at hospital discharge after major noncardiac surgery, but only the elderly (aged 60 years or older) are at significant risk for long-term cognitive problems. Patients with POCD are at an increased risk of death in the first year after surgery. Research interest has increased since early 2000, especially as more elderly patients are able to undergo successful minor and major surgeries.

POCD has been studied through various institutions since the inception of the IPOCDS-I study centred in Eindhoven, Netherlands and Copenhagen, Denmark. This study found no causal relationship between cerebral hypoxia and low blood pressure and POCD. Age, duration of anaesthesia, introperative complications, and postoperative infections were found to be associated with POCD.

- POCD is just as likely to occur after operations under regional anesthesia as under general anesthesia.

- More likely after major operations than minor operations.

- More likely after heart operations than other types of surgery.

- More likely in aged than in younger patients.

- More likely in older patients with high alcohol intake/abuse.

- People with higher preoperative ASA physical status scores are more likely to develop POCD.

- People with lower educational level are more likely to develop POCD than those with a higher educational level.

- People with prior history of a stroke, even though there is complete functional recovery, are more likely to develop POCD.

- More likely in the elderly with pre-existing declining mental functions, termed mild cognitive impairment (MCI). MCI is a transitional zone between normal mental function and evident Alzheimer's disease or other forms of dementia. It is insidious, and seldom recognized, except in retrospect after affected persons are evidently demented.

- Delirium and severe worsening of mental function is very likely in those with clinically evident Alzheimer's disease or other forms of dementia, as well as those with a history of delirium after previous operations.

Idiopathic craniofacial erythema is a medical condition characterised by severe, uncontrollable, and frequently unprovoked, facial blushing.

Blushing can occur at any time and is frequently triggered by even mundane events, such as, talking to friends, paying for goods in a shop, asking for directions or even simply making eye contact with another person.

For many years, the cause of the condition was thought to be an anxiety problem, caused by a mental health disorder. However, in recent years experts in the field of the disorder believe it to be caused by an overactive sympathetic nervous system, an automatic response which sufferers have no mental control over. It is related to focal hyperhidrosis, more commonly known as excessive sweating, as it is caused by the same overactive nerves which cause excessive sweating. Sufferers of severe facial blushing commonly experience focal hyperhidrosis. Studies have also shown that patients with severe facial blushing or focal hyperhidrosis commonly have family members with one or both of the related disorders.

A number of treatments are available. The most successful non-invasive procedure is cognitive behavioural therapy (CBT), which attempts to alleviate the anxiety felt by sufferers.

In extreme cases a surgical procedure known as endoscopic transthoracic sympathicotomy (ETS) is available. Pioneered by surgeons in Sweden, this procedure has recently become increasingly controversial due to its many potential adverse effects. Patients who have undergone the procedure frequently complain of compensatory sweating and fatigue, with around 5% reconsidering getting the treatment. ETS is now normally only considered in extreme cases where other treatments have been ineffective.

The body's inflammatory response to surgery likely plays an important role, at least in elderly patients. Various research initiatives during recent years have evaluated whether actions taken before, during and after surgery can lessen the possible deleterious effects of inflammation. For example, anti-inflammatory agents can be given before surgery. During surgery, inflammation can be modulated by temperature control, use of regional rather than general anesthesia or the use of beta blockers. After surgery, optimal pain management and infection control is important. Several studies have shown variable-significance positive effects when a multidisciplinary, multifactorial approach to elderly patient is followed during pre, peri and post-operative care.

Animal studies indicate that volatile anaesthestics may augment the pathological processes of Alzheimer's Disease by affecting amyloid-beta processing. However, in young healthy mice, the volatile anesthetic isoflurane can also produce long-lasting memory impairment. This adverse effect is preventable by pre-administering the GABA(A)α5 inverse agonist L-655,708.

Postanesthetic shivering (PAS) is shivering after anesthesia.

The intensity of PAS may be graded using the scale described by Crossley and Mahajan:

Postanesthetic shivering is one of the leading causes of discomfort in patients recovering from general anesthesia. It usually results due to the anesthetic inhibiting the body's thermoregulatory capability, although cutaneous vasodilation (triggered by post-operative pain) may also be a causative factor. First-line treatment consists of warming the patient; more persistent/severe cases may be treated with medications such as tramadol, pethidine, clonidine and nefopam, which work by reducing the shivering threshold temperature and reducing the patient's level of discomfort. As these medications may react and/or synergize with the anesthetic agents employed during the surgery, their use is generally avoided when possible.

Saddle anesthesia is a loss of sensation (anesthesia) restricted to the area of the buttocks, perineum and inner surfaces of the thighs.

It is frequently associated with the spine-related injury cauda equina syndrome. It is also seen in conus medullaris, the difference is that it is symmetrical in conus medullaris and asymmetric in cauda equina.It may also occur as a temporary side-effect of a sacral extra-dural injection:

A focal impaired awareness seizure is a seizure that is associated with unilateral cerebral hemisphere involvement and causes impairment of awareness or responsiveness, i.e. alteration of consciousness.

- Presentation

Focal impaired awareness seizures are often preceded by an aura. The seizure aura is a focal aware seizure. The aura may manifest itself as a feeling of déjà vu, jamais vu, fear, euphoria or depersonalization. The aura might also occur as a visual disturbance, such as tunnel vision or a change in the perceived size of objects. Once consciousness is impaired, the person may display automatisms such as lip smacking, chewing or swallowing. There may also be loss of memory (amnesia) surrounding the seizural event. The person may still be able to perform routine tasks such as walking, although such movements are not purposeful or planned. Witnesses may not recognize that anything is wrong.

Focal impaired awareness seizures might arise from any lobe of the brain. They most commonly arise from the temporal lobe, particularly the amygdala, hippocampus, and neocortical regions. A common associated brain abnormality is mesial temporal sclerosis. Mesial temporal sclerosis is a specific pattern of hippocampal neuronal loss accompanied by hippocampal gliosis and atrophy. Focal onset impaired awareness seizures occur when excessive and synchronous electrical brain activity causes the impaired awareness and responsiveness. The abnormal electrical activity might spread to the rest of the brain and cause a "focal to bilateral seizure" or a generalized tonic–clonic seizure. The newer classification of 2017 groups only focal and generalized seizures, and generalised seizures are those that involve both sides of the brain from the onset.

Involutional lipoatrophy is a cutaneous condition, and is an idiopathic lipoatrophy characterized clinically by non-inflammatory focal loss of fat.

Idiopathic localized involutional lipoatrophy (ILIL) is a rare and nosologically imprecise condition characterized by a focal loss of subcutaneous tissue on one or several sites, occurring without any significant triggering factor or auto-immune background, and regressing spontaneously within a few months.

Writer's cramp, also called mogigraphia and scrivener's palsy, is a disorder caused by cramps or spasms of certain muscles of the hand and/or forearm, and presents itself while performing fine motor tasks, such as writing or playing an instrument. Writer's cramp is a task-specific focal dystonia of the hand. 'Focal' refers to the symptoms being limited to one location (the hand in this case), and 'task-specific' means that symptoms first occur only when the individual engages in a particular activity. Writer's cramp first affects an individual by interfering with their ability to write, especially for prolonged periods of time.

Focal dystonia is a neurological condition, a type of "dystonia", that affects a muscle or group of muscles in a specific part of the body, causing involuntary muscular contractions and abnormal postures. For example, in focal hand dystonia, the fingers either curl into the palm or extend outward without control. In musicians, the condition is called "musician's focal dystonia", or simply, "musician's dystonia". In sports, it is commonly referred to as the "yips".

The exact incidence of Frey syndrome is unknown. The disorder most often occurs as a complication of the surgical removal of a parotid gland (parotidectomy). The percentage of individuals who develop Frey syndrome after a parotidectomy is controversial and reported estimates range from 30-50 percent. In follow-up examinations, approximately 15 percent of affected individuals rated their symptoms as severe. Frey syndrome affects males and females in equal numbers.

Anesthesia dolorosa or anaesthesia dolorosa or deafferentation pain is pain felt in an area (usually of the face) which is completely numb to touch. The pain is described as constant, burning, aching or severe. It can be a side effect of surgery involving any part of the trigeminal system, and occurs after 1–4% of peripheral surgery for trigeminal neuralgia. No effective medical therapy has yet been found. Several surgical techniques have been tried, with modest or mixed results. The value of surgical interventions is difficult to assess because published studies involve small numbers of mixed patient types and little long term follow-up.

- Gasserian ganglion stimulation is stimulation of the gasserian ganglion with electric pulses from a small generator implanted beneath the skin. There are mixed reports, including some reports of marked, some of moderate and some of no improvement. Further studies of more patients with longer follow-up are required to determine the efficacy of this treatment.

- Deep brain stimulation was found in one review to produce good results in forty-five percent of 106 cases. Though relief may not be permanent, several years of relief may be achieved with this technique.

- Mesencephalotomy is the damaging of the junction of the trigeminal tract and the periaqueductal gray in the brain, and has produced pain relief in a group of patients with cancer pain; but when applied to six anesthesia dolorosa patients, no pain relief was achieved, and the unpleasant sensation was in fact increased.

- Dorsal root entry zone lesioning, damaging the point where sensory nerve fibers meet spinal cord fibers, produced favorable results in some patients and poor results in others, with incidence of ataxia at 40%. Patient numbers were small, follow-up was short and existing evidence does not indicate long term efficacy.

- One surgeon treated thirty-five patients using trigeminal nucleotomy, damaging the nucleus caudalis, and reported 66% "abolition of allodynia and a marked reduction in or (less frequently) complete abolition of deep background pain."

Paroxysmal hand hematoma (also known as "Achenbach syndrome") is a skin condition characterized by spontaneous focal hemorrhage into the palm or the volar surface of a finger, which results in transitory localized pain, followed by rapid swelling and localized blueish discoloration.

Current medical science does not precisely describe the causes of dystonia. Misfiring of neurons in the sensorimotor cortex, a thin layer of neural tissue that covers the brain, is thought to cause contractions. This misfiring may result from impaired inhibitory mechanisms during muscle contraction. When the brain tells a given muscle to contract, it simultaneously silences muscles that would oppose the intended movement. It appears that dystonia interferes with the brain's ability to inhibit those surrounding muscles, leading to loss of selectivity.

The sensorimotor cortex is organized as discrete "maps" of the human body. Under normal conditions, each body part (such as individual fingers) occupies a distinct area on these cortical maps. In dystonia, these maps lose their distinct borders and overlap occurs. Exploration of this initially involved over-training particular finger movements in non-human primates, which resulted in the development of focal hand dystonia. Examination of the primary somatosensory cortex in the trained animals showed grossly distorted representations of the maps pertaining to the fingers when compared to the untrained animals. Additionally, these maps in the dystonic animals had lost the distinct borders that were noted in the untrained animals.

Imaging studies in humans with focal dystonia have confirmed this finding. Also, synchronous afferent stimulation of peripheral muscles induces organizational changes in motor representations, characterized both by an increase in map size of stimulated muscles and a reduction in map separation, as assessed using transcranial magnetic stimulation.

The cross-connectivity between areas that are normally segregated in the sensory cortex may prevent normal sensorimotor feedback and so contribute to the observed co-contraction of antagonist muscle groups, and inappropriately timed and sequenced movements that underlie the symptoms of focal dystonia. It is hypothesized that a deficit in inhibition caused by a genetically mediated loss of inhibitory interneurons may be the underlying cause of the deficits observed in dystonia.

While usually painless, in some instances the sustained contraction and abnormal posturing in dystonia cause pain. Focal dystonia most typically affects people who rely on fine motor skills—musicians, writers, surgeons, etc. It is thought that the excessive motor training those skills require may contribute to the development of dystonia as their cortical maps become enlarged and begin to overlap. Focal dystonia is generally "task-specific," meaning that it is only problematic during certain activities.