Dystonia

Question 1

What is dystonia? International Consensus Committee

Answer 1

• Movement disorder characterized by sustained or intermittent muscle contractions causing abnormal, repetitive movements, postures or both
• Initiated or worsened by voluntary action and associated with overflow muscle activation

Question 2

Former Classification System

Answer 2

1. Age of onset - Infantile (26)
2. Distribution - Focal, segmental, generalized, multifocal
3. Etiology - primary, secondary

Question 3

Current Classification

Answer 3

• Clinical Characteristics

- Etiology (NS; inherited v. acquired; idiopathic (sporadic v. familial)

Question 4

Prevalence of primary dystonia

Answer 4

• Early onset (2-50 cases per million)

- Late onset (30-7320 per million)

Question 5

Focal Dystonia

Answer 5

• Localized to one part of limb

- Task specific dystonia

Question 6

Generalized dystonia

Answer 6

• Involves trunk + 2 other body parts
• Many of these individuals cannot walk
• May not have dystonia with position changes

Question 7

Idiopathic, genetic dystonia

Answer 7

• No changes on standard imaging

- No underlying injury or disease

Question 8

Acquired dystonia

Answer 8

• Damage to multiple brain regions: basal ganglia, thalamus, brainstem, cerebellum cortex
• Injury to NS: Stroke, TBI, Limb injury
• Degenerative disease: Parkinson’s

Question 9

Neuroimaging for dystonia

Answer 9

• 18F-Fluorodeoxyglucos Study - brain metabolism
• PET Blood flow studies - activation patterns
• fMRI study - activation patterns
• Diffusion tensor imaging - microstructural changes
• Quantitative sturctural imaging - volumetric changes

Question 10

Abnormalities in brain sensorimotor circuitry

Answer 10

• Volumetric enlargement of basal ganglia
• Increased grey matter density in primary sensory cortex
• Increased metabolic activity in sensory and motor cortex during motor tasks
• Altered D2 dopamine receptor levels
• Impaired intracortical inhibition in sensory cortex

Question 11

Factors implicated in pathogenesis of dystonia

Answer 11

• Gene mutations
• Ion channel, intracellular signaling dysfunction
• Neurotransmitter dysfunction
• Reduced spatial/temporal discrimination
• Reduced surround inhibition
• Abberant/increased plasticity

Question 12

Surround inhibition with basal ganglia

Answer 12

• Modulate motor control by balancing excitation & inhibition of competing motor programs

Question 13

Basal ganglia disorders

Answer 13

• Inability to initiate movements
• Inability to suppress involuntary movements
• Abnormalities in velocity and amplitude of movement
• Abnormal muscle tone

Question 14

The linkage between what is a problem with dystonia?

Answer 14

Sensory inputs and motor outputs

Question 15

What is altered in dystonia?

Answer 15

• Postural patterns
• Neuroplasticity
• Link between posture and movement

Question 16

Sensori-motor integration with dystonia

Answer 16

• Normal inputs + altered processing = abnormal outputs

Question 17

Two circuits associated with basal ganglia and motor control

Answer 17

• Thalamocortical

- Brainstem motor

Question 18

What is wrong with the postural control system with dystonia?

Answer 18

• Abnormal amplification of one or more components of the brain postural control system

Question 19

Acquired dystonia & Stroke

Answer 19

• Tone/posturing of joint or body part that is not consistent with overall motor recovery of body part
• Dystonia seen in distal segments post-stroke

Question 20

Acquired dystonia and chronic regional pain syndrome

Answer 20

• Marked DF with inversion, knee flexion, hip flexion, external rotation
• Extremely disabling

Question 21

Acquired dystonia & Parkinson’s plus syndrome

Answer 21

• Excessive lateral trunk flexion, cervical flexion, trunk flexion

Question 22

Acquired dystonia & post-traumatic dystonia

Answer 22

• Developed following injury and can often be fixed

- Less responsive to treatment

Question 23

Acquired dystonia and paraneoplastic syndrome

Answer 23

• Rapid onset focal dystonia

- Occurs in non-contiguous body part

Question 24

Medical/Surgical treatment of dystonia

Answer 24

• Benzodiazepines - reduce excitability
• Trihexyphenidyl - synthetic anticholinergic
• Tetrabenazene - reduces dopamine and reduces movement
• Sinemet
• Botox - blocks Ach release
• DBS - given to GPI; primarily for generalized dystonia

Question 25

PT Exam for dystonia

Answer 25

• History
• Systems review
• Tests & measures
• Neuro exam (postural control, reflexes, oculomotor)
• Musculoskeletal (strength, ROM, joint mob)
• Sensation
• Response to postures
• Sensory tricks
• Assess spread

Question 26

Exam for writer’s cramp dystonia

Answer 26

• Look if activation in hand or forearm at rest
• Look at when activation occurs
• Look at if active when other hand performs task
• Look if dystonic posture occurs in alternate positions

Question 27

Exam for lower extremity dystonia

Answer 27

• Activation in foot or leg?

- Dystonic movement with alternate walking tasks?

Question 28

Exam for cervical dystonia

Answer 28

• Resting posture?
• Alleviating maneuvers?
• Difference in AROM in anti-gravity v gravity eliminated positions?
• Examine soft tissue, intervertebral mobility

Question 29

Exam for segmental/generalized dystonia

Answer 29

• Are there postures in which posturing or spasms are not present/diminished?
• Allow to assume whatever postures are most comfortable

Question 30

Goal of intervention

Answer 30

• Maximize quality of life/participation