Dystonia

INDEX

Dystonia is often present in Parkinson-plus syndromes, such as multiple system atrophy (MSA), progressive supranuclear palsy (PSP), and corticobasal degeneration (CBD).

 

 

 

 

 

 

 

Main types of dystonia and relative frequencies in Parkinson-Plus syndromes16.

From: Kanovsky P, Bhatia KP, Rosales RL. Dystonia and Dystonic Syndromes. (Kanovsky P, Bhatia KP, Rosales RL, eds.). Vienna: Springer Vienna; 2015. doi:10.1007/978-3-7091-1516-9

 

MSA

Dystonia is a common feature of MSA, occurring in almost half of cases.

Pisa syndrome

Anterocollis

Disproportionate anterocollis is considered a characteristic feature of this disease.

Laryngeal Stridor

Inspiratory stridor, particularly at night, is commonly attributed to vocal cord paralysis, though it might also reflect dystonia of the vocal cords.

Limb Dystonia

Limb dystonia in MSA includes dystonic arm posturing, task-specific dystonia (such as writer’s cramp), or equinovarus foot posturing. Limb dystonia is most likely to occur in MSA subjects who are levodopa naïve and tends to improve with dopamine therapy.

PSP

Limb Dystonia

Limb involvement is the most common dystonic manifestation of PSP patients.  Hemidystonia may be a very early feature of this disease in some patients and can lead to a diagnosis of CBD because of the pronounced unilateral dystonia.  Single limb involvement is described in 10 % of PSP cases, with the arm being the limb affected most often.

Blepharospasm

This is well known to occur in PSP; up to 50 % of the PSP patients with blepharospasm may display apraxia of eyelid opening.  Blepharospasm is often a late manifestation of the disease, there being a few cases in which this symptom occurs as an early manifestation, whereas apraxia of eyelid opening or closing frequently appears in the middle stages of the disease.

Retrocollis

Retrocollis associated with axial rigidity is most typically seen in patients with the classic variant of PSP (Richardson’s syndrome).  Some authors do not consider this neck posture to be dystonic, since, it is not associated with muscle hypertrophy nor can it be relieved by a geste, both being typical features of classical cervical dystonia.

Laryngeal dystonia may also occur, potentially causing confusion with MSA.

CORTICOBASAL DEGENERATION

A number of pathological substrates that may underlie corticobasal syndrome (CBS) include a wide range of pathologies, such as PSP, Alzheimer’s dementia, Pick’s disease, frontotemporal lobar degeneration with ubiquitin- and TDP-43- positive inclusions, Lewy body disease, frontotemporal lobar degeneration with fused-in sarcoma-positive inclusions, and Creutzfeldt-Jakob disease.

The majority of early-onset dystonic CBD patients display a CBS phenotype, while the remainder have a PSP phenotype.

The majority of patients with late-onset dystonic CBD display a “dementia” phenotype (FTD, AD, or progressive nonfluent aphasia).