What is Dystonia? Different types and diagnosis

Joaquin Farias PHD, MA, MS

Dystonia, a neurological movement disorder, manifests in involuntary muscle contractions, resulting in slow, repetitive movements and occasional discomfort. Similar to the myriad forms this condition takes, dystonia can impact a single muscle, muscle groups, or the entire body, with symptom severity varying among individuals.

Unraveling Neurological Complexity

Defined by unintended muscle contractions, dystonia can arise independently or as a consequence of other conditions, some with hereditary roots. When the cause of the symptoms is known the condition is called Secondary Dystonia. When no cause is identified they are classified as Primary Dystonias (idiopathic).

Deciphering the Indicators: A Spectrum of Dystonic Symptoms

Initial symptoms may be subtle, emerging after exertion or stress and gradually intensifying over time. Symptoms range from occasional foot cramps, irregular foot movements, and deteriorating handwriting to involuntary neck turns, uncontrollable eye blinking, eye twitches, tremors, and speech difficulties. The evolution of dystonia sees intermittent movements during stress progressing to visible postures even during relaxation.

Harmony in Diversity: The Taxonomy of Dystonia

Dystonia’s onset spans all ages, categorised as early or adult onset. Early onset often originates in limbs, progressing with fluctuations throughout the day. Adult onset typically targets adjacent body parts, predominantly the neck and facial muscles. Classification involves two axes: clinical features (age, affected region, specific traits, associated problems) and causes (known or unknown, genetic, or Inter-individual differences in human brain structure and morphology).

Exploring Body Regions and Dystonic Varieties

Dystonia manifests in diverse forms. Generalised dystonia impacts the entire body, while focal dystonia localises to specific areas. Multifocal dystonia involves unrelated body parts, segmental dystonia affects adjacent parts, and hemidystonia involves the same-side arm and leg. Notable forms of Focal Dystonias include Hand Focal Dystonias (Writters’ Cramp), Cervical Dystonia/ Spasmodic Torticollis, affecting neck muscles, and Blepharospasm, causing involuntary eye blinking leading to “functional blindness.”

Cranial dystonia affects head, face, and neck muscles, sometimes accompanied by blepharospasm, labeled Meige syndrome. Oromandibular Dystonia involves jaw, lips, and tongue muscles, influencing speech and swallowing. Spasmodic Dysphonia targets vocal cord muscles, resulting in strained speech.

Task-Specific Dystonias: A Focused Inquiry

Parallel to Musician-Focal dystonias, Task-Specific Focal Dystonias emerge during particular activities. Instances include Writer’s cramp affecting hand and forearm muscles during handwriting. These focal dystonias, resembling typist’s or pianist’s cramp, underscore the unique challenges dystonia poses during specific tasks.