Dystonia Flashcards
What is dystonia? International Consensus Committee
- 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
Former Classification System
- Age of onset - Infantile (26)
- Distribution - Focal, segmental, generalized, multifocal
- Etiology - primary, secondary
Current Classification
- Clinical Characteristics
- Etiology (NS; inherited v. acquired; idiopathic (sporadic v. familial)
Prevalence of primary dystonia
- Early onset (2-50 cases per million)
- Late onset (30-7320 per million)
Focal Dystonia
- Localized to one part of limb
- Task specific dystonia
Generalized dystonia
- Involves trunk + 2 other body parts
- Many of these individuals cannot walk
- May not have dystonia with position changes
Idiopathic, genetic dystonia
- No changes on standard imaging
- No underlying injury or disease
Acquired dystonia
- Damage to multiple brain regions: basal ganglia, thalamus, brainstem, cerebellum cortex
- Injury to NS: Stroke, TBI, Limb injury
- Degenerative disease: Parkinson’s
Neuroimaging for dystonia
- 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
Abnormalities in brain sensorimotor circuitry
- 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
Factors implicated in pathogenesis of dystonia
- Gene mutations
- Ion channel, intracellular signaling dysfunction
- Neurotransmitter dysfunction
- Reduced spatial/temporal discrimination
- Reduced surround inhibition
- Abberant/increased plasticity
Surround inhibition with basal ganglia
- Modulate motor control by balancing excitation & inhibition of competing motor programs
Basal ganglia disorders
- Inability to initiate movements
- Inability to suppress involuntary movements
- Abnormalities in velocity and amplitude of movement
- Abnormal muscle tone
The linkage between what is a problem with dystonia?
Sensory inputs and motor outputs
What is altered in dystonia?
- Postural patterns
- Neuroplasticity
- Link between posture and movement
Sensori-motor integration with dystonia
- Normal inputs + altered processing = abnormal outputs
Two circuits associated with basal ganglia and motor control
- Thalamocortical
- Brainstem motor
What is wrong with the postural control system with dystonia?
- Abnormal amplification of one or more components of the brain postural control system
Acquired dystonia & Stroke
- 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
Acquired dystonia and chronic regional pain syndrome
- Marked DF with inversion, knee flexion, hip flexion, external rotation
- Extremely disabling
Acquired dystonia & Parkinson’s plus syndrome
- Excessive lateral trunk flexion, cervical flexion, trunk flexion
Acquired dystonia & post-traumatic dystonia
- Developed following injury and can often be fixed
- Less responsive to treatment
Acquired dystonia and paraneoplastic syndrome
- Rapid onset focal dystonia
- Occurs in non-contiguous body part
Medical/Surgical treatment of dystonia
- 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
PT Exam for dystonia
- History
- Systems review
- Tests & measures
- Neuro exam (postural control, reflexes, oculomotor)
- Musculoskeletal (strength, ROM, joint mob)
- Sensation
- Response to postures
- Sensory tricks
- Assess spread
Exam for writer’s cramp dystonia
- 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
Exam for lower extremity dystonia
- Activation in foot or leg?
- Dystonic movement with alternate walking tasks?
Exam for cervical dystonia
- Resting posture?
- Alleviating maneuvers?
- Difference in AROM in anti-gravity v gravity eliminated positions?
- Examine soft tissue, intervertebral mobility
Exam for segmental/generalized dystonia
- Are there postures in which posturing or spasms are not present/diminished?
- Allow to assume whatever postures are most comfortable
Goal of intervention
- Maximize quality of life/participation
