Introduction 

Cervical dystonia (CD), also known as spasmodic torticollis, is the most common type of focal dystonia. Focal dystonia is a neurological movement disorder that often affects one area of the body, such as the face, neck or hands. It is characterised by involuntary muscle contractions, which causes abnormal postures in the targeted area. In CD, neck muscles contract involuntarily, producing patterned, repetitive movements and abnormal postures in the head and neck.¹

Studies have shown that the prevalence of CD is uncertain, with some reports estimating an incidence of 1.18 cases per 100,000 population annually. Often, diagnostic setbacks and misdiagnoses can cause significant treatment delays, worsening patient suffering. 

Why is CD often misdiagnosed? 

Cervical distonia is relatively rare and often unfamiliar to general practitioners and non-specialists. This can lead to the under- or misdiagnosis of the condition. Training in recognising CD is limited, which can cause diagnostic delays of four to five years.² CD presents heterogeneity, meaning patients do not show the same posture or movement pattern, and exhibit subtypes depending on which neck muscles are most overactive. 

• Torticollis is the most common manifestation of CD. It is characterized by the rotation of the head to one side, and involves the trapezius, scapular capsular ligaments or sternocleidomastoid (SCM)
• Laterocollis is a subtype of CD involving the tilting of the head towards one shoulder and the overactivity of the SCM
• Retrocolis is characterized by the backwards extension of the head, as well as overactivity of the posterior neck extensors
• Anterocolis involves forward flexion of head and neck, as well as bilateral overactivity of sternocleidomastoids

Conditions that mimic CD symptoms include: 

• Orthopaedic or rheumatological fixed deformities
• Lower motor neuron weakness
• Ocular torticollis 
• Chorea, head tics or other neurological mimics 

Distinguishing between functional and organic CD

A major challenge in the diagnosis of CD is distinguishing idiopathic or organic CD from functional dystonia. As they share clinical signs and neurophysical traits, functional presentation often mimics that of CD. Functional CCD is a subtype of functional neurological disorders, where abnormal movement occurs without a structural neurological disease. The symptoms arise from altered brain network functioning. In functional CD, the onset is often sudden, and the movement pattern is inconsistent. Sensory tricks (light-specific sensory input), such as a light touch to the chin, do nothing to improve the posture of a functional CD.

Clinical and systems level barriers to misdiagnosis

Even if clinical suspicion is raised, assessment relies on subjective examinations, with the absence of an objective diagnostic test leading to confusion due to the lack of clarity.⁵ Many clinicians have limited exposure to CD during their training and practice, which can delay recognition of the disorder and prevent further referral to movement disorder specialists. CD also has a wide range of mimics with orthopaedic neuromuscular or physiatrist causes, which CD is often misattributed, especially as these disorders are more common. Referral delays can also be cut due to limited specialist access, especially in more rural areas. Socioeconomic factors can also influence misdiagnosis rates, as specialists might not always be covered via insurance. Lower socioeconomic status (SES) patients reported a higher prevalence, whilst those with higher SES reported more recurrences. This is because those of a lower SES have limited access to specialist care, whilst those with a higher SES benefit from greater medical intervention, follow-up and opportunities for reassessment. 

Diagnostic tools for CD

Clinical features that are common in CD include repetitive head and neck postures or patterned movements that deviate from the neutral positions. Sensory tricks, such as a light touch on the chin or head, have been shown to improve symptoms of CD.⁶  In clinical practice, the diagnosis of CD relies not only on recognising positive features but also on the absence of red flags. A fixed immobile posture usually points to an orthopaedic cause, such as arthritis, while focal weakness in antagonistic muscles suggests a neuromuscular disorder like myasthenia gravis. Importantly, in tic disorders, the movement can often be voluntarily suppressed, whereas CD spasms are involuntary and only relieved by a sensory trick. These distinctions help clinicians separate CD from common mimics and avoid misdiagnosis. 

As of 2023, there have been guidelines that provide six key clinical terms in order to either rule in or out CD. Secondary causes can be ruled out via imaging or labs. In order to differentiate between FD or organic CD, an assessment is required to assess incontinence, distal by as well as objective signs. It is important to adopt a multidisciplinary approach involving specialists in neurology, physiology and psychiatry. 

Consequences of misdiagnosis

A delayed diagnosis can worsen a patient's suffering, affecting quality of life and mental health. Some patients will endure unnecessary treatment before receiving appropriate care. A large proportion of CD patients undergo inappropriate tests, which can be invasive, time-consuming and expensive. These often include MRIs, X-rays, blood tests, as well as inappropriate treatment such as anti-inflammatories, muscle relaxants and physical therapy. A diagnostic process involving repeated physician visits, extensive testing, or inappropriate treatments can impose a significant strain on public healthcare resources as well as on the patient. Likewise, a delay in receiving therapy can also reduce its potential benefits. 

It is important to educate frontline clinicians about CD hallmark signs, such as abnormal head and neck postures as well as patterned movements. It is also crucial to train clinicians to recognize mimics, in order to help better distinguish between the diagnoses. A diagnostic checklist will help patients receive an accurate diagnosis and reduce the number of misdiagnoses. Clinicians should also encourage referrals to movement disorder specialists when CD is suspected, rather than brushing off symptoms as stress-induced. In order for the patient to receive the best quality of care, a multidisciplinary team including specialists in neurology, physiotherapy and psychiatry should be engaged. Finally, patients should be informed about the possibility of a CD diagnosis and educated on sensory tricks to help identify and manage their symptoms. 

Summary

Misdiagnosis and diagnostic delay in CD remain significant issues, with many patients experiencing incorrect diagnosis and postponed treatment. These errors come from variable symptomatology, overlapping mimics, clinician unfamiliarity with the disorder and a lack of objective diagnostic tests to help identify the condition. Structured diagnostic tools, elevated treatment options, and an early referral to a movement disorder specialist are likely to improve patient outcomes.