Stiff Person Syndrome: Early Symptoms, Diagnosis, Treatment and Life Expectancy
Stiff person syndrome is a rare neurological condition that can cause persistent muscle stiffness, painful spasms and an unusually strong physical response to sound, touch, movement or emotional distress.
The name can make the condition sound deceptively simple. It is not ordinary muscular stiffness, nor is it the stiffness many people experience after exercise, injury or sitting in one position for too long. In stiff person syndrome, the nervous system has difficulty controlling muscle activity. Muscles may remain active when they should be relaxed, leaving the person feeling rigid, vulnerable to sudden spasms and increasingly cautious about movement.
The condition varies enormously. One person may experience stiffness mainly through the lower back and legs. Another may have severe spasms that interfere with walking, sleeping, working or leaving the house. Some people respond well to treatment and remain independent. Others develop substantial disability or additional neurological problems.
Because stiff person syndrome is rare and resembles several more common conditions, diagnosis is frequently complicated. Symptoms can initially be attributed to back trouble, anxiety, dystonia, Parkinson’s disease, multiple sclerosis or a functional neurological disorder. Understanding the characteristic pattern of stiffness, triggers and spasms can therefore be important.
Stiff person syndrome at a glance
Stiff person syndrome, often shortened to SPS, is:
A rare disorder affecting the central nervous system
Usually considered an immune-mediated or autoimmune neurological condition
Characterised by muscle rigidity and painful, involuntary spasms
Frequently associated with sensitivity to noise, touch, movement and emotional stress
Often linked with antibodies against glutamic acid decarboxylase, particularly GAD65
Diagnosed using the clinical history, neurological examination, antibody testing and sometimes electromyography
Treated with a combination of symptom-controlling medicines, immune treatment and rehabilitation
The condition affects the brain and spinal cord rather than being a primary disease of the muscles themselves. The US Genetic and Rare Diseases Information Center describes extreme stiffness, rigidity and painful spasms involving the trunk and limbs, sometimes with severe impairment of mobility.
What is stiff person syndrome?
Muscle movement depends on a balance between signals that activate muscles and signals that restrain excessive activity. One of the important inhibitory chemicals in the nervous system is gamma-aminobutyric acid, better known as GABA.
Many people with stiff person syndrome have antibodies against an enzyme called glutamic acid decarboxylase, or GAD. This enzyme helps produce GABA. The most frequently discussed antibody is the GAD65 antibody.
The exact relationship between these antibodies and the illness remains complex. GAD65 antibodies support the diagnosis when they are present at a high level alongside a typical clinical picture, but an antibody result cannot diagnose stiff person syndrome by itself. GAD antibodies can also occur in people with type 1 diabetes and other autoimmune neurological conditions. Some people with convincing stiff person syndrome do not have detectable GAD65 antibodies.
Other antibodies associated with the stiff person spectrum include glycine receptor antibodies and amphiphysin antibodies. Amphiphysin antibodies are particularly relevant when doctors are considering a paraneoplastic form associated with an underlying cancer. NHS neuroimmunology laboratories recognise GAD, amphiphysin and glycine receptor antibodies as markers that may be relevant to stiff person spectrum disorders.
What are the early symptoms of stiff person syndrome?
The early symptoms of stiff person syndrome are not identical in everyone. They may develop gradually and can fluctuate, particularly at the beginning.
A common early pattern is unexplained stiffness through the central part of the body, especially the abdomen, lower back or muscles running alongside the spine. The person may feel that their trunk is unusually rigid or that it is difficult to bend, turn or relax normally.
Early signs may include:
Persistent stiffness in the lower back or abdomen
The abdominal and back muscles may feel constantly tense, even when the person is resting. This can be mistaken for a back injury, poor posture or muscular strain.
The stiffness may be worse during stress, after sudden movement or in unfamiliar surroundings. Some people notice that their body feels “board-like” rather than simply sore.
Intermittent painful muscle spasms
Spasms may initially occur only occasionally. They can involve the back, abdomen, hips or legs and may be extremely painful.
Unlike a typical leg cramp, an SPS spasm may affect several muscle groups at once. The person may arch, become temporarily rigid or feel unable to control their posture.
An exaggerated startle response
A sudden noise, unexpected touch or rapid movement may cause an abnormally intense physical reaction. A door slamming, a car horn or someone touching the person unexpectedly can trigger a jerk or full muscular spasm.
This stimulus sensitivity is one of the features that can help distinguish stiff person syndrome from ordinary muscular tension.
Changes in walking
The person may begin to walk stiffly, take shorter steps or feel that their legs do not move naturally. Turning, walking through crowded spaces or stepping across uneven ground may become difficult.
Some people develop episodes of gait freezing or feel unable to initiate movement when frightened or startled.
Increasing fear of falling
Fear of walking outdoors or crossing open spaces is sometimes interpreted purely as anxiety. In SPS, however, the fear may arise because the person has experienced sudden spasms, freezing or falls.
The anxiety is real, but it may be a consequence of unpredictable physical symptoms rather than their original cause. Orphanet includes task-specific fear related to walking and an exaggerated startle response within the recognised stiff person spectrum.
Changes in posture
Continuous contraction of the spinal muscles can produce an exaggerated inward curve of the lower back, known as lumbar hyperlordosis. In other cases, long-standing stiffness may eventually contribute to a hunched or fixed posture.
Symptoms that come and go
Early stiffness may be worse on some days than others. A person can therefore appear relatively mobile during one appointment but be severely affected in a different environment.
The fluctuating nature of the condition can delay diagnosis, particularly when symptoms are triggered by circumstances that are difficult to reproduce during a short examination.
What do stiff person syndrome spasms feel like?
Descriptions differ, but people commonly report a sudden, forceful tightening that they cannot voluntarily stop. The spasm may feel as though the body has locked, snapped backwards or become rigid from the waist down.
Spasms can last seconds or longer and may occur repeatedly. Some are localised to one limb, while others involve much of the body.
The force can be considerable. Severe spasms may cause falls and have occasionally been associated with fractures. NIH information notes that spasms may be forceful enough to injure bone, although this is not what happens in every case.
Pain may come from the contraction itself, from sustained muscular rigidity or from injuries caused by falling. Some people also experience pain between obvious spasms because their muscles never fully relax.
What triggers stiff person syndrome spasms?
Recognised triggers include:
Sudden or loud noises
Unexpected physical contact
Rapid movements
Cold temperatures
Crowded or unfamiliar environments
Emotional distress
Fear or anticipation of a spasm
Painful procedures or physical discomfort
These triggers do not mean the condition is “all in the mind”. Emotional stress can influence activity throughout the nervous system and may provoke genuine involuntary contractions in someone with SPS.
Anticipatory fear can also create a difficult cycle. A person who has fallen after being startled may become understandably frightened of walking outside. That fear can increase muscular tension and sensitivity, making movement even harder.
Are there different types of stiff person syndrome?
Doctors increasingly use the broader term stiff person spectrum disorder because the illness does not always follow the classic pattern.
Classic stiff person syndrome
Classic SPS usually causes progressive stiffness in the trunk and proximal limbs, painful stimulus-sensitive spasms, altered posture and difficulty walking.
The abdominal and lower spinal muscles are often particularly affected.
Stiff-limb syndrome
In stiff-limb syndrome, symptoms begin predominantly in one arm or leg. Painful spasms, rigidity and difficulty using the affected limb may remain relatively localised for some time, although the condition can later spread.
Stiff person syndrome plus
The term SPS-plus may be used when typical stiffness and spasms occur alongside additional neurological features. These can include problems with balance, eye movements, speech or other brainstem and cerebellar functions.
Progressive encephalomyelitis with rigidity and myoclonus
Progressive encephalomyelitis with rigidity and myoclonus, or PERM, is a more severe disorder within the stiff person spectrum.
PERM can cause rigidity, spasms, exaggerated startle responses, sudden jerks, brainstem symptoms and disturbance of involuntary functions such as heart rate, blood pressure or breathing. It is often associated with glycine receptor antibodies and can be life-threatening, particularly when respiratory or autonomic complications occur.
Paraneoplastic stiff person syndrome
A minority of cases are associated with cancer. This is called a paraneoplastic neurological syndrome, in which the immune response directed against a tumour also attacks part of the nervous system.
Breast cancer, small-cell lung cancer, thymoma and certain blood cancers have been reported in association with stiff person spectrum disorders, although the presence of SPS does not automatically mean that a person has cancer.
The clinical pattern, age, antibody results and other symptoms help doctors decide whether cancer investigations are appropriate.
How rare is stiff person syndrome?
SPS is unquestionably rare, but its exact frequency is uncertain.
Older descriptions commonly suggested approximately one affected person per million. More recent research indicates that the true prevalence may be higher, partly because the condition is now recognised as a spectrum and because older cases may have been missed or misclassified.
A 2024 population-based health-system study reported estimates ranging from approximately 1.36 to 2.11 cases per 100,000 people, depending on how strictly the diagnostic criteria were applied. The researchers cautioned that the findings came from one healthcare system and that prevalence changed according to case definition.
This uncertainty is a useful reminder that a rare disease statistic is not always a fixed fact. Better recognition, different diagnostic criteria and improved antibody testing can all change estimated prevalence.
Who is more likely to develop stiff person syndrome?
Symptoms most often begin in adulthood, but SPS can occur across a wide age range, including in children and older adults. NIH rare-disease information notes that symptoms may begin at many different ages.
Women appear to be affected more often than men. SPS is also associated with other autoimmune conditions, particularly:
Type 1 diabetes
Autoimmune thyroid disease
Vitiligo
Pernicious anaemia
Coeliac disease in some patients
Other autoimmune neurological disorders
Having one of these conditions does not mean that someone will develop SPS. Their presence may, however, support the possibility of an autoimmune background when characteristic neurological symptoms are also present.
Is stiff person syndrome hereditary?
Classic autoimmune stiff person syndrome is not generally considered a straightforward inherited disorder. Most affected people do not have a clear family history of SPS, and there is no single SPS gene passed predictably from parent to child.
Genetic factors may influence a person’s susceptibility to autoimmune disease, but this is different from saying that SPS itself is usually inherited.
Several inherited neurological and muscular disorders can also cause stiffness. Doctors may consider these alternatives when symptoms begin in infancy or childhood, when several family members are affected or when the clinical pattern does not fit autoimmune SPS.
How is stiff person syndrome diagnosed?
There is no single test that can confirm every case. Diagnosis usually depends on whether the person’s symptoms, examination findings and test results form a convincing overall pattern.
A specialist assessment commonly includes the following.
A detailed symptom history
The neurologist will ask:
Where the stiffness began
Whether it is continuous or intermittent
Which muscles are affected
What triggers the spasms
Whether falls or injuries have occurred
Whether walking changes in open, crowded or unfamiliar spaces
Whether symptoms affect swallowing, speech or breathing
Whether autoimmune diseases or cancer are present
Which medicines improve or worsen the symptoms
Videos recorded safely by a family member can occasionally help when attacks do not occur during the appointment.
Neurological examination
The doctor will assess posture, muscle tone, reflexes, strength, coordination, walking and the response to movement or stimulation.
People with classic SPS may have marked rigidity despite relatively preserved muscle strength, although the examination varies considerably between patients.
Antibody blood tests
Blood may be tested for antibodies including:
GAD65
Glycine receptor antibodies
Amphiphysin antibodies
Other antibodies when the clinical picture suggests a wider autoimmune or paraneoplastic syndrome
A positive result must be interpreted in context. High GAD65 antibody levels are more supportive than a weakly positive result, but neither a positive nor a negative test should be viewed in isolation. Recent work on diagnostic features found that high-titre GAD65 antibodies were particularly useful when combined with the appropriate clinical phenotype.
Electromyography
Electromyography, or EMG, records electrical activity in muscles.
In SPS, EMG may demonstrate continuous motor unit activity even when the person is attempting to relax. Activity in opposing muscle groups at the same time can also support the diagnosis.
The test is helpful, but its sensitivity can depend on which muscles are examined, the person’s medication and the stage or distribution of the condition.
Lumbar puncture
A sample of cerebrospinal fluid may be taken in selected cases. This can help identify antibodies or inflammation within the central nervous system and exclude infections or other inflammatory disorders.
MRI and other investigations
MRI scans are often performed not because SPS has a single characteristic MRI appearance, but to rule out structural disease of the brain or spinal cord.
Further tests may investigate nutritional deficiencies, metabolic problems, infections, genetic conditions, other autoimmune diseases or an underlying malignancy.
What conditions can be mistaken for stiff person syndrome?
The symptoms overlap with several neurological and musculoskeletal disorders. Possible alternatives include:
Dystonia
Parkinsonian disorders
Multiple sclerosis
Spinal cord compression or myelopathy
Hereditary spastic paraplegia
Tetanus
Neuromyotonia or Isaacs syndrome
Hereditary hyperekplexia
Functional neurological disorder
Severe anxiety with muscular tension
Muscular or orthopaedic back disorders
Medication-related rigidity
Other autoimmune encephalomyelitis syndromes
Functional neurological disorder is particularly important to discuss carefully. FND is a genuine neurological disorder and is not the same as inventing symptoms. At the same time, some people with SPS have reportedly received an FND or psychiatric diagnosis before the stiff person pattern was recognised.
The reverse problem also exists: diagnosing SPS solely because an antibody is present can lead to incorrect treatment. Specialist interpretation is therefore essential.
Is stiff person syndrome the same as multiple sclerosis?
No. Stiff person syndrome and multiple sclerosis are separate neurological conditions.
Both involve the central nervous system and both may have an autoimmune component, but they usually produce different clinical patterns.
Multiple sclerosis typically involves inflammatory damage to myelin and may cause sensory loss, visual symptoms, weakness, balance disturbance and distinct abnormalities on MRI.
SPS is more strongly characterised by continuous rigidity, stimulus-sensitive spasms and excessive involuntary muscle activity. MRI may be normal or may be used mainly to exclude other diagnoses.
A person should not try to distinguish the two conditions using symptoms alone. Neurological examination, imaging, antibody results and electrophysiology may all be needed.
Can stiff person syndrome be cured?
There is currently no established cure that permanently removes SPS in every patient.
That does not mean nothing can be done. Treatment may substantially reduce stiffness and spasms, improve mobility, prevent injuries and control immune activity. Some people obtain good long-term symptom control, while others need several treatments before finding a useful combination.
Treatment is usually divided into three areas:
Medicines that reduce stiffness and spasms
Treatments directed at the immune system
Rehabilitation and practical support
Medicines for stiffness and spasms
Benzodiazepines such as diazepam are frequently used because they increase GABA-related inhibition and can reduce rigidity and spasms.
Baclofen is another common treatment. It acts through GABA-B receptors and may be taken orally. In selected severe cases, specialist teams may consider an intrathecal baclofen pump, which delivers medicine around the spinal cord.
Other medicines sometimes used include:
Gabapentin
Pregabalin
Tizanidine
Dantrolene
Clonazepam
Other pain-relieving or antispasmodic medicines
These medicines can cause sedation, dizziness, weakness, impaired coordination or dependence. Doses generally need to be adjusted gradually and monitored carefully. Abruptly stopping benzodiazepines or baclofen can be dangerous.
The US National Institute of Neurological Disorders and Stroke lists diazepam, baclofen, gabapentin, dantrolene and tizanidine among medicines used to control SPS symptoms.
Immune treatments
Because SPS is usually considered immune-mediated, some people receive treatments intended to modify the abnormal immune response.
Intravenous immunoglobulin
Intravenous immunoglobulin, commonly called IVIG, is one of the most established immune treatments for autoimmune SPS.
It is given through a vein, often in repeated courses. Some patients experience reduced stiffness, fewer spasms and better mobility, although the response is not universal and may diminish between treatments.
A 2025 systematic review found that evidence remains limited by the rarity of SPS and the small size of many studies, but IVIG had the most consistent support among immune-directed treatments.
Rituximab
Rituximab targets B cells, which are involved in antibody production.
Some patients have improved considerably with rituximab, while controlled research has produced mixed results. It may still be considered in selected difficult-to-treat cases after specialist review.
Plasma exchange
Plasma exchange removes circulating plasma containing antibodies and replaces it with another fluid. It is sometimes used in severe or rapidly worsening cases, although the evidence is less consistent than for IVIG.
Corticosteroids and other immunosuppressants
Steroids or other immune-suppressing medicines may be considered in certain patients, particularly when there are overlapping inflammatory features.
Treatment decisions depend on the SPS subtype, antibody findings, other illnesses, infection risk and previous response. Many therapies are used off-label because conducting large trials in such a rare condition is difficult.
Physiotherapy and rehabilitation
Physiotherapy can be valuable, but it must be adapted to the individual.
Forcing a rigid limb or performing aggressive stretching can trigger pain or spasms. A physiotherapist familiar with neurological rigidity can instead work gradually on:
Safe movement
Maintaining joint range
Posture
Balance
Transfers
Walking aids
Breathing and relaxation strategies
Reducing the risk of falls
Occupational therapists can assess the home, workplace and daily routines. Equipment such as rails, shower seats, mobility aids or adapted seating may help a person remain independent.
Treatment should acknowledge that fear of movement may be based on previous falls and real physical triggers. Simply telling someone to “push through” can be counterproductive.
Living with stiff person syndrome
Daily life often involves more than taking medication.
A person may need to plan around fatigue, unpredictable symptoms and environments likely to provoke spasms. Practical measures can include:
Allowing extra time for journeys
Avoiding sudden physical contact
Warning medical staff about startle-sensitive spasms
Reducing unnecessary background noise
Wearing supportive footwear
Using a walking aid when advised
Installing rails or removing trip hazards
Carrying an up-to-date medication list
Having a plan for severe attacks
Explaining the condition to family members and employers
Some people become socially isolated because they are frightened of falling in public or being startled in a crowd. Psychological support can be useful, not because the illness is imaginary, but because living with an unpredictable disabling condition can understandably cause anxiety, low mood and loss of confidence.
Can someone with stiff person syndrome still walk?
Many people with SPS continue to walk, particularly when symptoms are recognised and treated early. Others need a stick, frame, wheelchair or assistance during periods of greater disability.
Walking ability can fluctuate. Someone who walks inside a quiet home may freeze or spasm in a crowded station because sound, stress and unexpected contact create additional triggers.
Needing a wheelchair does not always mean that a person has permanently lost all ability to stand or walk. It may be used to prevent falls, conserve energy or allow safe participation outside the home.
How quickly does stiff person syndrome progress?
There is no single timetable.
Classic SPS often develops gradually over months or years. Stiffness may begin in the trunk before spreading to the legs. As the condition progresses, spasms can become more frequent and walking may become less secure.
Some people remain relatively stable for long periods. Others experience stepwise deterioration, severe exacerbations or a more rapidly progressive variant.
Treatment can alter the course. A 2026 study of long-term outcomes reported that although more than half of the studied patients lost functional independence at the lowest point of their illness, many subsequently regained independence and achieved well-controlled symptoms. This supports a more nuanced outlook than assuming that deterioration is always continuous and irreversible.
What is the life expectancy with stiff person syndrome?
There is no reliable single life-expectancy figure for stiff person syndrome.
This is partly because SPS is rare, the severity varies widely and older studies often combined people with very different forms of the disorder. Someone with well-controlled classic SPS cannot automatically be compared with someone who has rapidly progressive PERM or a cancer-associated paraneoplastic syndrome.
SPS is not generally described as an inevitably fatal disease. Many people live for years or decades following diagnosis. Some may have a lifespan close to what would otherwise be expected, especially when symptoms are controlled and serious complications are avoided.
However, it would be equally inaccurate to say that SPS never affects survival. Potentially serious complications include:
Injuries and fractures following falls
Breathing impairment in severe disease
Swallowing problems and aspiration
Reduced mobility and associated complications
Severe autonomic instability in PERM
Infections
Adverse effects from treatment
An associated cancer in paraneoplastic cases
For that reason, the most honest answer to “How long can someone live with stiff person syndrome?” is that prognosis must be assessed individually. The subtype, speed of progression, response to treatment, mobility, breathing and swallowing function, associated autoimmune disease and presence or absence of cancer all matter.
Websites that provide a precise average number of years without explaining these limitations should be treated cautiously.
Can stiff person syndrome affect breathing or swallowing?
Classic SPS most often affects the trunk and limbs, but severe stiffness or spasms can interfere with breathing mechanics. Some spectrum disorders can involve muscles related to the throat, chest or brainstem.
Difficulty swallowing, repeated choking, new changes in speech, shortness of breath or prolonged spasms affecting the chest require prompt medical assessment.
Respiratory and autonomic problems are particularly concerning in PERM and other severe SPS-plus presentations.
When should someone seek urgent medical help?
Emergency assessment is appropriate when a person has:
Severe difficulty breathing
Blue or grey discolouration around the lips
Loss of consciousness
A serious injury following a fall
A prolonged severe spasm that does not settle as expected
New inability to swallow saliva
Repeated choking
Sudden marked weakness or new neurological symptoms
Chest pain or symptoms suggestive of another medical emergency
Not every worsening episode is caused by SPS. Infection, medication withdrawal, electrolyte disturbance, stroke and other acute illnesses can produce stiffness or spasms and may need urgent treatment.
Questions to ask a neurologist
Useful questions may include:
Does my symptom pattern meet recognised SPS criteria?
How strong was my antibody result, and how should it be interpreted?
Do I need an EMG?
Have structural spinal problems and other mimics been excluded?
Is this classic SPS, stiff-limb syndrome, SPS-plus or PERM?
Is there any reason to investigate for cancer?
Which treatment is aimed at symptoms and which is aimed at the immune system?
What side effects should I watch for?
What should I do during a severe spasm?
Would neurological physiotherapy or occupational therapy help?
Which symptoms should lead me to seek urgent care?
Frequently asked questions
Does stiff person syndrome cause constant pain?
It can. Some people have continuous muscular aching or tightness, while others experience pain mainly during spasms. Falls, altered posture and sustained muscle contraction can add further pain.
Can stress cause stiff person syndrome?
Stress is not considered the sole cause of SPS. Emotional distress can trigger or intensify spasms in someone who already has the neurological condition.
Can stiff person syndrome symptoms come and go?
Yes. The severity of stiffness and spasms may fluctuate. Symptoms can change according to the environment, medication timing, stress, fatigue and exposure to triggers.
Is a positive GAD65 test enough to diagnose SPS?
No. GAD65 antibodies can occur in other conditions, especially type 1 diabetes. The level of the antibody, the clinical pattern, examination and other investigations all need to be considered.
Can a person have SPS with a negative antibody test?
Yes. Some clinically convincing cases are seronegative, meaning that currently available tests do not identify a recognised antibody.
Which doctor diagnoses stiff person syndrome?
Diagnosis is normally made by a neurologist. A movement-disorder neurologist or neuroimmunologist may be particularly helpful when the presentation is complicated.
Is stiff person syndrome a muscular disease?
The symptoms are experienced in the muscles, but the underlying problem is neurological. It involves abnormal control of muscle activity by the central nervous system.
Does stiff person syndrome affect intelligence?
Classic SPS is primarily a movement and muscle-control disorder and does not usually imply loss of intelligence. Some broader spectrum disorders can cause additional neurological symptoms, so each case must be assessed individually.
Is stiff person syndrome fatal?
It is not inevitably fatal, and many people live for a long time with the condition. Severe variants and complications involving breathing, swallowing, autonomic function, injuries or cancer can nevertheless be life-threatening.
A realistic outlook
Stiff person syndrome can be profoundly disabling, but its course is not the same for everyone. The diagnosis does not automatically mean that a person will rapidly lose mobility or have a shortened life.
Treatment may require patience. Medicines that work well for one person may provide limited benefit or unacceptable side effects for another. Immune therapy can help some patients considerably, but responses are variable and treatment often needs to be reviewed over time.
The most useful approach is usually coordinated care involving neurology, physiotherapy, occupational therapy, primary care, pain management and psychological support where appropriate. Early recognition also matters because repeated falls, fixed posture, avoidant movement and social isolation can become harder to reverse once established.
Above all, unexplained stiffness should not be assumed to be SPS simply because the condition has become better known. It remains rare, and many more common disorders can produce similar symptoms. Diagnosis should rest on a careful neurological assessment rather than an internet symptom list or a single antibody result.
Medical disclaimer
This article is provided for general education and does not diagnose stiff person syndrome or replace individual medical advice. Muscle stiffness and spasms can have many causes. Anyone concerned about persistent rigidity, painful spasms, unexplained falls, swallowing difficulty or breathing symptoms should seek assessment from an appropriately qualified healthcare professional. Do not start, stop or alter prescribed medication without medical advice.
References and further reading
National Institute of Neurological Disorders and Stroke. Stiff-Person Syndrome. Updated May 2026.
NIH Genetic and Rare Diseases Information Center. Stiff-person syndrome. Updated June 2026.
Dalakas MC. Stiff-person syndrome and related disorders: diagnosis, mechanisms and therapies. 2024.
Bose S and colleagues. Stiff-person syndrome. Practical Neurology, 2025.
Lenglet T and colleagues. Systematic Review of Immune and Symptomatic Treatments for Stiff-Person Syndrome. 2025.
Crane PD and colleagues. Population-Based Study of the Epidemiology of Stiff Person Syndrome. 2024.
Orphanet. Stiff person spectrum disorder and Progressive encephalomyelitis with rigidity and myoclonus.
Mangioris G and colleagues. Long-Term Outcomes in Stiff Person Spectrum Disorder. 2026.