Dystonia: Cervical Dystonia & Blepharospasm
Dystonia: Torticollis & Blepharospasm
Dystonia: Overview
- It involves involuntary, sustained, intermittent muscle contraction that causes abnormal posturing or movements.
- Dystonia can affect a wide variety of body parts, can occur in a wide variety of distributions, patterns, and speeds.
- Seemingly almost any body part can be affected but the most common are the limbs, neck, trunk, eyelids (blepharospasm) and other facial muscles, or even the vocal cords, themselves.
- It can occur in a continuous or intermittent pattern and it can be focal or generalized or almost anything in between (segmental, multifocal, hemi-body).
- The speed of contraction can be quick and fleeting like chorea or myoclonus, often called dystonic spasm, or it can be slow and sustained or cramp-like (athetoic), in which it is often called a dystonic posture.
- If generalized (generalized dystonia, DYT), large body parts are typically involved, which can cause extreme distortion from the sustained writhing and twisting that can occur.
Cervical Dystonia
- It is the most common form of focal dystonia.
- In cervical dystonia, there is, most commonly, spasmodic torticollis (turning or twisting: a rotation) of the neck.
- Less commonly, there may be retrocollis (backward, extension) or anterocollis (forward, flexion) or laterocollis (tilted to the side).
- Importantly, via a sensory trick (geste antagoniste), individuals can perform a maneuver such as lightly touching their face to release the dystonic posture.
Writer's cramp
- The next most common focal dystonia (after cervical dystonia) is writer's cramp, which is brought on by that very action (writing).
Blepharospasm
As opposed to hemifacial spasm...
- Blepharospasm (aka nictatating spasm) involves bilateral (rather than unilateral) repetitive involuntary squeezing of the eyelids (eyelid closure) via spams of the orbicularis oculi and frontalis muscles and is most often idiopathic (not secondary to neurovascular compression), although it can be part of various syndromes, such as parkinsonism and Wilson's disease.
Blepharospasm is best categorized as a dystonia rather than a twitch or tic for the following reasons:
- The eyelid closure in blepharospasm is typically brief (like a twitch) but the patient can experience persistent squeezing to the point of sustained eyelid closure (typical of dystonia), in which case the patient can be functionally blind.
- Just like with cervical dystonia, a light touch to the lateral aspect of the eye can interrupt the eyelid closure.
- When involuntary blinking is a motor tic, it is suppressible and the patient experiences a compulsion to shut the eyes, neither of which are part of blepharospasm.
Meige Syndrome
- Meige syndrome refers to blepharospasm in combination with oromandibular dystonia (lower facial and jaw muscle involvement).