Diagnosis can be achieved through a specialized form of electromyographic (EMG) testing called the long exercise test. This test measures the amplitude of a nerve response (called the Compound Muscle Action Potential or CMAP) for 40 to 50 minutes following a few minutes of exercise. In affected patients, there is a progressive fall in the amplitude of the potential. Besides the patient history or a report of serum potassium low normal or low during an attack, the long exercise test is the current standard for medical testing. Genetic diagnosis is often unreliable as only a few of the more common gene locations are tested, but even with more extensive testing 20–37% of people with a clinical diagnosis of hypokalemic periodic paralysis have no known mutation in the two known genes. Standard EMG testing cannot diagnose a patient unless they are in a full blown attack at the time of testing. Provoking an attack with exercise and diet then trying oral potassium can be diagnostic, but also dangerous as this form of PP has an alternate form known as hyperkalemic periodic paralysis. The symptoms are almost the same, but the treatment is different. The old glucose insulin challenge is dangerous and risky to the point of being life-threatening and should never be done when other options are so readily available.

People with hypokalemic periodic paralysis are often misdiagnosed as having a conversion disorder or hysterical paralysis since the weakness is muscle-based and doesn't correspond to nerve or spinal root distributions. The tendency of people with hypokalemic periodic paralysis to get paralyzed when epinephrine is released in "fight or flight" situations further adds to the temptation to misdiagnose the disorder as psychiatric.

This disease is unusually difficult to diagnose. Patients often report years of wrong diagnosis and treatments that made them worse instead of better. Part of this may be that migraines are present in up to 50% of patients and can cause a confusing array of symptoms including headaches, speech difficulties and visual, auditory or sensory auras. DNA testing is available for only a half dozen common gene mutations, while dozens of known mutations are possible but are not routinely tested. Electromyography (EMG) findings are not specific but the McManis Protocol, also called the Compound Muscle Amplitude Potential test (CMAP)can be used by a skilled neurologist capable of utilizing the EMG, which can give assistance in diagnosing several of these PP disorders. The old glucose/insulin provocative testing can cause life-threatening symptoms and should not be used.

Also of note is that potassium levels do "not" have to range outside of normal limits to cause serious, even life-threatening paralysis. These diseases are "not" the same as having a very low level of potassium (hypokalemia) or high potassium (hyperkalemia) and must not be treated as such. The total body store of potassium is usually normal; it is just in the wrong place.

The most effective way to detect fasciculations may be surface electromyography (EMG). Surface EMG is more sensitive than needle electromyography and clinical observation in the detection of fasciculation in people with amyotrophic lateral sclerosis.

Weber's syndrome is the only form of alternating hemiplegia that is somewhat easy to diagnose beyond the general criteria. Although Weber's syndrome is rare, a child born with the disorder typically has a port-wine stain on the face around the eye. While the port-wine stain does not necessarily mean the child has Weber's syndrome, if the port-wine stain involves the ophthalmic division of the trigeminal nerve than the likelihood of it being weber's syndrome greatly increases. If a port-wine stain around the eye is found, the patient should be screened for intracranial leptomeningeal angiomatosis. Magnetic resonance imaging (MRI)can be used to determine the presence and severity while computed cranial tomography can be used to determine the effect. MRI is the preferred diagnostic test on children presenting with port-wine stain. Other imaging techniques can be used in addition to further determine the severity of the disorder. The initial diagnosis is made based on the presence of neurologic and ophthalmic disease but the disease progresses differently in each patient so after initial diagnosis the patient should be monitored frequently in order to handle further complications resulting from the syndrome.

The degree of tremor should be assessed in four positions. The tremor can then be classified by which position most accentuates the tremor:

The prognosis for periodic paralysis varies. Overactivity, a diet that is not low in sodium and carbohydrates, or simply an unfortunate gene mutation can lead to a type of chronic, low level weakness called an "abortive attack," or to permanent muscle damage. Abortive attacks often respond to extra potassium, cutting carbohydrates, getting plenty of rest, increasing doses of medication and gentle daily exercise such as short walks. Permanent muscle weakness is just what it sounds like: Permanent, irreparable damage to the muscles and associated weakness. Vacuoles and tubular aggregates form in and destroy healthy muscle tissue. This type of damage can typically be observed via a muscle biopsy. Not even anabolic steroids can repair this type of muscular damage.

Life span is expected to be normal, but attacks can drop potassium to levels low enough to cause life-threatening breathing problems or heart arrhythmia. Patients often report muscle pain and cognitive problems during attacks. Migraines occur in up to 50% of all hypokalemic periodic paralysis patients and may include less common symptoms like phantom smells, sensitivity to light and sound or loss of words. Medical literatures states that muscle strength is normal between attacks, but patients often report that their baseline strength is in fact lower than that of healthy individuals.

Because there are dozens of possible gene mutations, some drugs and treatments that work fine for one patient will not work for another. For example, most patients do well on acetazolamide, but some don't. Some patients will do well with extra magnesium (the body's natural ion channel blocker) or fish oil, while these same nutrients will make other patients worse. Patients and caregivers should take extreme caution with all new drugs and treatment plans.

There is no diagnostic test for alternating hemiplegia, which makes it very difficult to diagnose. Also, because alternating hemiplegia is extremely rare, it is frequently missed and the patient is often misdiagnosed. Proper diagnosis, however, is critical for early treatment of the disorder. There are many criteria that can help in the proper general diagnosis of alternating hemiplegia.

During a physical exam a doctor can determine whether the tremor occurs primarily during action or at rest. The doctor will also check for tremor symmetry, any sensory loss, weakness or muscle atrophy, or decreased reflexes. A detailed family history may indicate if the tremor is inherited. Blood or urine tests can detect thyroid malfunction, other metabolic causes, and abnormal levels of certain chemicals that can cause tremor. These tests may also help to identify contributing causes, such as drug interaction, chronic alcoholism, or another condition or disease. Diagnostic imaging using CT or MRI imaging may help determine if the tremor is the result of a structural defect or degeneration of the brain.

The doctor will perform a neurological examination to assess nerve function and motor and sensory skills. The tests are designed to determine any functional limitations, such as difficulty with handwriting or the ability to hold a utensil or cup. The patient may be asked to place a finger on the tip of her or his nose, draw a spiral, or perform other tasks or exercises.

The doctor may order an electromyogram to diagnose muscle or nerve problems. This test measures involuntary muscle activity and muscle response to nerve stimulation. The selection of the sensors used is important. In addition to studies of muscle activity, tremor can be assessed with accuracy using accelerometers .

Treatment of the periodic paralyses may include carbonic anhydrase inhibitors (such as acetazolamide, methazolamide or dichlorphenamide), taking supplemental oral potassium chloride and a potassium-sparing diuretic (for hypos) or avoiding potassium (for hypers), thiazide diuretics to increase the amount of potassium excreted by the kidneys (for hypers), and significant lifestyle changes including tightly controlled levels of exercise or activity. However, treatment should be tailored to the particular type of periodic paralysis.

Treatment of periodic paralysis in Andersen-Tawil syndrome is similar to that for other types. However, pacemaker insertion or an implantable cardioverter-defibrillator may be required to control cardiac symptoms.

Diagnosis of paramyotonia congenita is made upon evaluation of patient symptoms and case history. Myotonia must increase with exercise or movement and usually must worsen in cold temperatures. Patients that present with permanent weakness are normally not characterized as having PC. Electromyography may be used to distinguish between paramyotonia congenita and myotonia congenita. Clinicians may also attempt to provoke episodes or myotonia and weakness/paralysis in patients in order to determine whether the patient has PC, hyperkalemic periodic paralysis, or one of the potassium-aggravated myotonias. Genomic sequencing of the SCN4A gene is the definitive diagnostic determinant.

Inadequate magnesium intake can cause fasciculations, especially after a magnesium loss due to severe diarrhea. Over-exertion and heavy alcohol consumption are also risk factors for magnesium loss. As 70–80% of the adult population does not consume the recommended daily amount of magnesium, inadequate intake may also be a common cause. Treatment consists of increased intake of magnesium from dietary sources such as nuts (especially almonds), bananas, and spinach. Magnesium supplements or pharmaceutical magnesium preparations may also be taken. However, too much magnesium may cause diarrhea, resulting in dehydration and nutrient loss (including magnesium itself, leading to a net loss, rather than a gain). It is well known as a laxative (Milk of Magnesia), though chelated magnesium can largely reduce this effect. Cheaper methods of the chelation process may be unsatisfactory for some people (e.g. mild diarrhea). Magnesium supplements recommend that they be taken only with meals, and not on an empty stomach.

Fasciculation also often occurs during a rest period after sustained stress, such as that brought on by unconsciously tense muscles. Reducing stress and anxiety is therefore another useful treatment.

There is no proven treatment for fasciculations in people with ALS. Among patients with ALS, fasciculation frequency is not associated with the duration of ALS and is independent of the degree of limb weakness and limb atrophy. No prediction of ALS disease duration can be made based on fasciculation frequency alone.

Assessment of motor control may involve several health professionals depending on the affected individual's situation, and the severity of their condition. This may include physical therapists, physicians (including neurologists and psychiatrists ) and rehabilitation physicians, orthotists, occupational therapists, and speech-language pathologists. Assessment is needed of the affected individual's goals, their function, and any symptoms that may be related to the movement disorder, such as pain. A thorough assessment then uses a clinical reasoning approach to determine why difficulties are occurring. Elements of assessment will include analysis of posture, active movement, muscle strength, movement control and coordination, and endurance, as well as muscle tone and spasticity. Impaired muscles typically demonstrate a loss of selective movement, including a loss of eccentric control (decreased ability to actively lengthen); this decreased active lengthening of a muscle is a key factor that limits motor control. While multiple muscles in a limb are usually affected in the Upper Motor Neuron Syndrome, there is usually an imbalance of muscle activity (muscle tone), such that there is a stronger pull on one side of a joint, such as into elbow flexion. Decreasing the degree of this imbalance is a common focus of muscle strengthening programs. Impaired motor control also typically features a loss of stabilisation of an affected limb or the head from the trunk, so a thorough assessment requires this to be analysed as well, and exercise to improve proximal stability may be indicated.

Secondary effects are likely to impact on assessment of impaired muscles. If muscle tone is assessed with passive muscle lengthening, increased muscle stiffness may affect the feeling of resistance to passive stretch, in addition to neurological resistance to stretch. Other secondary changes such as loss of muscle fibres following acquired muscle weakness are likely to compound the weakness arising from the upper motor neuron lesion. In severely affected muscles, there may be marked secondary changes, such as muscle contracture, particularly if management has been delayed or absent.

Therapeutic interventions are best individualized to particular patients.

Basic principles of treatment for hypertonia are to avoid noxious stimuli and provide frequent range of motion exercise.

The use of oral potassium and avoiding high carbohydrate meals can help treat it according to resent tests. Dr. Jacob O. Levitt, a dermatologist who has hypokalemic periodic paralysis, recently conducted research in to it.

The prognosis for those with spastic muscles depends on multiple factors, including the severity of the spasticity and the associated movement disorder, access to specialised and intensive management, and ability of the affected individual to maintain the management plan (particularly an exercise program). Most people with a significant UMN lesion will have ongoing impairment, but most of these will be able to make progress. The most important factor to indicate ability to progress is seeing improvement, but improvement in many spastic movement disorders may not be seen until the affected individual receives help from a specialised team or health professional.

Physiotherapy has been shown to be effective in controlling hypertonia through the use of stretching aimed to reduce motor neuron excitability. The aim of a physical therapy session could be to inhibit excessive tone as far as possible, give the patient a sensation of normal position and movement, and to facilitate normal movement patterns. While static stretch has been the classical means to increase range of motion, PNF stretching has been used in many clinical settings to effectively reduce muscle spasticity.

Icing and other topical anesthetics may decrease the reflexive activity for short period of time in order to facilitate motor function. Inhibitory pressure (applying firm pressure over muscle tendon) and promoting body heat retention and rhythmic rotation (slow repeated rotation of affected body part to stimulate relaxation) have also been proposed as potential methods to decrease hypertonia. Aside from static stretch casting, splinting techniques are extremely valuable to extend joint range of motion lost to hypertonicity. A more unconventional method for limiting tone is to deploy quick repeated passive movements to an involved joint in cyclical fashion; this has also been demonstrated to show results on persons without physical disabilities. For a more permanent state of improvement, exercise and patient education is imperative. Isokinetic, aerobic, and strength training exercises should be performed as prescribed by a physiotherapist, and stressful situations that may cause increased tone should be minimized or avoided.

Paratonia is the inability to relax muscles during muscle tone assessment. There are two types of paratonia: oppositional and facilitatory. Oppositional paratonia ("gegenhalten") occurs when subjects involuntary resist to passive movements, while facilitatory paratonia ("mitgehen") occurs when subjects involuntary assist passive movements.

Both types of paratonia have been associated with cognitive impairment or mental disorders, particularly in relation to frontal lobe dysfunction. Paratonia is frequently encountered in clinical practice.

Paratonia can be assessed with rating scales during clinical examination. Paratonia scale is a semi-quantitative score to rate the amount of oppositional and facilitatory paratonia separately. Kral modified procedure is a more objective semi-quantitative rating of upper limb facilitatory paratonia easily applicable while patients are seated. The Paratonia Assessment Instrument (PAI) was also used in a physiotherapic setting for the assessment of oppositional paratonia.

In 2017 facilitatory and oppositional paratonia have been assessed with surface electromyography, allowing a quantitative measure and better characterization of paratonia. Recording paratonia with electromyography on elbow flexor and extensors during repetitive continuous or discontinuous elbow movements may help distinguish paratonia from other forms of altered muscle tone. Both facilitatory and oppositional paratonia increase during continuous flexion and extension movements, moreover, oppositional paratonia increases with movement velocity. Spasticity also is velocity-dependent, but, differently from oppositional paratonia, if repeatedly elicited decreases instead of increasing. Conversely, parkinsonian rigidity is independent from movement velocity and probably also from movement repetition.

Treatment should be based on assessment by the relevant health professionals. For muscles with mild-to-moderate impairment, exercise should be the mainstay of management, and is likely to need to be prescribed by a physical therapist or other health professional skilled in neurological rehabilitation.

Muscles with severe impairment are likely to be more limited in their ability to exercise, and may require help to do this. They may require additional interventions, to manage the greater neurological impairment and also greater secondary complications. These interventions may include serial casting, flexibility exercise such as sustained positioning programs, and medical interventions.

Research has clearly shown that exercise is beneficial for impaired muscles, even though it was previously believed that strength exercise would "increase" muscle tone and impair muscle performance further. Also, in previous decades there has been a strong focus on other interventions for impaired muscles, particularly stretching and splinting, but the evidence does not support these as effective. One of the challenges for health professionals working with UMNS movement disorders is that the degree of muscle weakness makes developing an exercise programme difficult. For muscles that lack any volitional control, such as after complete spinal cord injury, exercise may be assisted, and may require equipment, such as using a standing frame to sustain a standing position. Often, muscles require specific stimulation to achieve small amounts of activity, which is most often achieved by weight-bearing (e.g. positioning and supporting a limb such that it supports body weight) or by stimulation to the muscle belly (such as electrical stimulation or vibration).

Medical interventions may include such medications as baclofen, diazepam, dantrolene, or clonazepam. Phenol injections or botulinum toxin injections into the muscle belly can be used to attempt to dampen the signals between nerve and muscle. The effectiveness of medications varies between individuals, and varies based on location of the upper motor neuron lesion (in the brain or the spinal cord). Medications are commonly used for movement disorders, but research has not shown functional benefit for some drugs. Some studies have shown that medications have been effective in decreasing spasticity, but that this has not been accompanied by functional benefits.

Doublecortin positive cells, Similar to stem cells, are extremely adaptable and, when extracted from a brain, cultured and then re-injected in a lesioned area of the same brain, they can help repair and rebuild it. The treatment using them would take some time to be available for general public use, as it has to clear regulations and trials.

There are a variety of standardized assessment scales available to physiotherapists and other health care professionals for use in the ongoing evaluation of the status of a patient’s hemiplegia. The use of standardized assessment scales may help physiotherapists and other health care professionals during the course of their treatment plant to:

- Prioritize treatment interventions based on specific identifiable motor and sensory deficits

- Create appropriate short- and long-term goals for treatment based on the outcome of the scales, their professional expertise and the desires of the patient

- Evaluate the potential burden of care and monitor any changes based on either improving or declining scores

Some of the most commonly used scales in the assessment of hemiplegia are:

- The Fugl-Meyer Assessment of Physical Performance (FMA)

The FMA is often used as a measure of functional or physical impairment following a cerebrovascular accident (CVA). It measures sensory and motor impairment of the upper and lower extremities, balance in several positions, range of motion, and pain. This test is a reliable and valid measure in measuring post-stroke impairments related to stroke recovery. A lower score in each component of the test indicates higher impairment and a lower functional level for that area. The maximum score for each component is 66 for the upper extremities, 34 for the lower extremities, and 14 for balance. Administration of the FMA should be done after reviewing a training manual.

- The Chedoke-McMaster Stroke Assessment (CMSA)

This test is a reliable measure of two separate components evaluating both motor impairment and disability. The disability component assesses any changes in physical function including gross motor function and walking ability. The disability inventory can have a maximum score of 100 with 70 from the gross motor index and 30 from the walking index. Each task in this inventory has a maximum score of seven except for the 2 minute walk test which is out of two. The impairment component of the test evaluates the upper and lower extremities, postural control and pain. The impairment inventory focuses on the seven stages of recovery from stroke from flaccid paralysis to normal motor functioning. A training workshop is recommended if the measure is being utilized for the purpose of data collection.

- The Stroke Rehabilitation Assessment of Movement (STREAM)

The STREAM consists of 30 test items involving upper-limb movements, lower-limb movements, and basic mobility items. It is a clinical measure of voluntary movements and general mobility (rolling, bridging, sit-to-stand, standing, stepping, walking and stairs) following a stroke. The voluntary movement part of the assessment is measured using a 3-point ordinal scale (unable to perform, partial performance, and complete performance) and the mobility part of the assessment uses a 4-point ordinal scale (unable, partial, complete with aid, complete no aid). The maximum score one can receive on the STREAM is a 70 (20 for each limb score and 30 for mobility score). The higher the score, the better movement and mobility is available for the individual being scored.

Diagnosis of Rhythmic Movement Disorder is done on an exclusionary basis in which other closely related movement disorders are systematically ruled out. Because of this, a thorough clinical evaluation is necessary. Often, impairments are not severe enough to warrant this process and so RMD is not often diagnosed unless there are extremely interfering or disabling symptoms. Many patients do not seek treatment for RMD directly and most seek professional help to alleviate sleep-affecting symptoms. To compound the issue, many sufferers are often misdiagnosed as having Restless Legs Syndrome or sleep apnea or some combination of the two. Rhythmic Movement Disorder differs from Restless Legs Syndrome in that RMD involves involuntary contractions of muscles with no urge or uncomfortable sensation to provoke such movement. Additionally, 80-90% of Restless Legs Syndrome sufferers show periodic limb movements as observed on a polysomnogram, which are not common in RMD patients. Rhythmic Movement Disorder can also have symptoms that overlap with epilepsy. However, use of a polysomnogram can help distinguish one disorder from the other as RMD involves movements in both REM and NREM sleep, which is unusual for seizures

. Additionally, patients can usually stop the movements upon request, unlike the movements observed in epilepsy. Other movement disorders like Parkinson’s Disease, Huntington’s Disease, ataxia, and dystonia differ from RMD in that they occur primarily during wakefulness and reduced sleep, whereas RMD episodes occur in or around sleep

It can reduce the effectiveness of the sodium-channel blocker lidocaine in dental work, so the amide-type local anesthetic. articaine is used on victims instead.

Paroxysmal Dyskinesia is not a fatal disease. Life can be extremely difficult with this disease depending on the severity. The prognosis of PD is extremely difficult to determine because the disease varies from person to person. The attacks for PKD can be reduced and managed with proper anticonvulsants, but there is no particular end in sight for any of the PD diseases. PKD has been described to cease for some patients after the age of 20, and two patients have reported to have a family history of the disease where PKD went into complete remission after the age of 23. With PNKD and PED, at this time, there is no proper way to determine an accurate prognosis.

Hemiplegia is identified by clinical examination by a health professional, such as a physiotherapist or doctor. Radiological studies like a CT scan or magnetic resonance imaging of the brain should be used to confirm injury in the brain and spinal cord, but alone cannot be used to identify movement disorders. Individuals who develop seizures may undergo tests to determine where the focus of excess electrical activity is.

Hemiplegia patients usually show a characteristic gait. The leg on the affected side is extended and internally rotated and is swung in a wide, lateral arc rather than lifted in order to move it forward. The upper limb on the same side is also adducted at the shoulder, flexed at the elbow, and pronated at the wrist with the thumb tucked into the palm and the fingers curled around it.

Diagnosis is similar, but slightly different for each type of PD. Some types are more understood than others, and therefore have more criteria for diagnosis.