SF: (7) Dystonia

Abnormal sensory processing - mapping in the brain

*Abnormal somatosensory map* - Map disorganized and maybe overlapping - People with focal hand dystonia have decreased spatial discrimination in finger somatotopic map

Dystonia - biopsychosocial components

*BIO* = physical impairments *PSYCHO* = psychological impairments - Motivation, self-efficacy: reduce catastrophizing, encourage/improvement is possible, help patient plan for appropriate dose/type of activity - Stress and depression management: may need psych consult or other therapies, adapt environment to reduce triggers *SOCIAL* = social impairments - Need to identify when rest or social support is needed - Connect patient w/ local support group - May need resources to educate others on disorder (family support) - Encourage regular exercise in any activity they tolerance

Deficient inhibitory systems - M1

*Decreased intracortical inhibition in M1* - In focal hand dystonia and in vocal dystonia, there is lower levels of cortical inhibition

Dystonia pathophysiology - role of the cerebellum

*Dento-thalamic-cortical pathway* = dentate nucleus to striatum (via the intralaminar thalamic nuclei) - Cb interacts with thalamus to influence the striatum, as well as the brainstem and cortex In mice models, NA pump blocker to disrupt Cb function causes dystonia to increase; but this dystonia decreases when Cb output to the basal ganglia was reduced/severed - Suggests that dystonia can be *caused by abnormal Cb output* and *reduced by eliminating Cb drive to basal ganglia*

Deficient inhibitory systems - brainstem

*Increased brainstem excitability* --> increased blink reflex - Early and late reflex in controls - Stimulation before reduces blink reflex in controls, but not in patients w/ eye dystonia

Dystonia pathophysiology - abnormal/excessive plasticity

*Maladaptive plasticity* - Dystonia = disorganized, overlapping, unregulated - VS. healthy brain = organized, maintained

Involuntary muscle activity - study on dystonia and spasticity in children with CP

- *Dystonia* associated w/ excessive muscle activity during *active movement* - *Spasticity* associated with excessive muscle activity during *quick stretch* - Study also shows that dystonia and spasticity CAN present at the same time in children with CP

Dystonia - what is it?

- *Hyperkinetic* movement disorders characterized by *sustained or intermittent* muscle contractions causing abnormal, often repetitive movements, postures, or both - Task-dependent

Dystonia intervention approaches - *movement practice* (3)

- *Intensive motor practice and training* to recover *voluntary control* of the affected body part - Do so by *breaking down complex movements* to retrain the brain - Principles (3): 1. *Find basic, small amplitude movements* w/ fewest muscles involved (as little motor flow as possible); play w/ position (supine, sidelying, gravity dependent, walking) and difficulty (arm movement, dual task) 2. *Bilateral and unilateral coordination training* - improving communication b/t hemispheres 3. *Posture and alignment training* - improve sense of upright

Abnormal sensory processing presents as... (2 examples)

- *Reduced sensory discrimination* - Deficits seen *globally*, not specific to the body region effected - Examples: 1. Reduced arm proprioception in vocal dystonia 2. Reduced temporal discrimination in eye dystonia

Dystonia - prevalence

- 3rd most common movement disorder (after essential tremor and PD) - Cervical dystonia is the most common form of dystonia (2x more common in women)

Motor characteristics of dystonia - *dystonic tremor*

- A spontaneous oscillatory, rhythmical, often inconsistent patterned movement produced by contractions of dystonic muscles - Often exacerbated by attempt to hold "normal" posture - May be posture-specific - Different from an essential tremor

Dystonia intervention approaches - *normalization of muscle activity with external techniques* (4)

- Application of external methods (active or passive) to normalize muscle activity levels and regain function - Take advantage of sensory tricks whenever possible - Examples: 1. *TENS* - reduce pain to normalize movement 2. *Kinesiotape* - inhibit affected muscles or place on sensory trick areas 3. *Dry needling* - relaxing muscle +/- may have central effects or induce central reorganization 4. *Biofeedback* - always incorporate in neurologic populations (e.g. hand on muscle training)

Dystonia treatments - botox mechanism of action

- Block ACh at the NMJ - May have central effects (change sensory processing)

Special consideration for manual therapy in patients with dystonia

- Cannot ask patient to relax - Positioning considerations are extra important

Dystonia pathophysiology - involved structures (3)

- Cause is complex and not fully understood - Think of dystonia as a *network dysfunction* involving: 1. Cb 2. Basal ganglia 3. Cerebral cortex - sensory and motor cortices

Motor characteristics of dystonia - *motor overflow*

- Commonly found in dystonia - Presents as unintentional muscle contraction which accompanies, but is anatomically distinct from the primary dystonic movement - Muscles that are not normally involved become active (antagonists or distant muscles)

Dystonia treatments - botox schedule

- Currently the BEST intervention for dystonia - Takes *1 week* to start seeing relaxation - Effect peaks *~4 weeks* = best time to provide PT - Slowly wears off over ~11 weeks (body metabolizes botox) - Reinjection at 4-12 weeks

Hypertonicity Assessment Tool (HAT) - purpose

- Delineates between dystonia, spasticity and rigidity - 7 items - Score 0 for negative or 1 for positive - Items 1, 2 and 6, if positive, suggest dystonia: 1. Increased involuntary movements/postures of the designated limb w/ tactile stimulus of another body part 2. Increased involuntary movements/postures with purposeful movements of another body part 6. Increased tone with movement of another body part

Likelihood of spread for focal vs. genetic vs. secondary dystonia

- Focal = generally stays focal; e.g. guitar players that switch hands often develop dystonia in other hand - Genetic/childhood = likely to develop into generalized dystonia - Secondary = typically symptoms do not progress unless primary condition is progressing; spontaneous recovery possible in rare cases

Dystonia intervention approaches - *sensory reorganization* (2)

- Focus on reorganization of the cortical sensory map to induce motor improvement - Goal = to improve body *perception with manual, tactile, verbal, and visual training* - Two methods to reorganize boundaries of sensorimotor cortex: 1. *Sensory deprivation* - e.g. not playing instrument for 1 month to decrease symptoms 2. *Sensorimotor discrimination retraining* - use different weights, textures, timing of stimuli

Dystonia - why is it important to identify the type (primary vs. secondary)

- Guides prognosis and treatment! *Primary* - Normal diagnostic workup - Prognosis = may spread to other body - Tx plan = may respond well to re-training principles *Secondary* - Abnormal diagnostic workup (e.g. lesion in brain on MRI) - Prognosis = likely will NOT spread to other body regions - Tx plan = address primary diagnosis first

Deficient inhibitory systems - abnormal transcollosal inhibition (study)

- Healthy = balanced transcallosal inhibition - Dystonia = asymmetric or reduced transcallosal inhibition on one side (e.g. L-->R transcallosal inhibition; may relate to hand dominance) - Example: in hand dystonia, decreased transcallosal tone, related to symptom severity

Dystonia pathophysiology - abnormal DA function

- Increased activity of the *direct (D1) pathway* facilitates movement --> hyperkinetic movement disorder - Reduced activity of the indirect (D2) pathway - However, dystonia is a *network disorder*, so its more than just striatal output (must consider the *cerebellum*)

Muscle activation in dystonia (EMG)

- Loss of muscle specificity = all muscle turn ON together - Reflects motor overflow - Caused by *increased/disorganized cortical drive* --> abnormal muscle tone emerges or is exacerbated by voluntary movement

Abnormal/excessive plasticity - Byl et al. 1996 study on monkeys

- Monkeys completed an intensive 20-week training program of a complex hand task - Somatotopic map of specific muscles became smeared, with reduced discrete borders b/t muscle representations (overlapping) - Symptoms of dystonia emerged

Task specificity in focal dystonia - 3 common examples

- Most frequently present in *hand and oral dystonia* - Dystonic movement occurs only during a *specific task or posture* - Examples: 1. Writer's dystonia 2. Musician's dystonia 3. Runner's dystonia

Abnormal/excessive plasticity - Quartarone et al. 1998 study on paired associative stimulation (PAS)

- PAS = method to induce sensory-motor neuroplasticity by pairing a sensory stimulus w/ depolarization of the motor cortex - In this study, stimulate median nerve and then stimulate brain via TMS - Dystonia subjects = MEP increased excessively after PAS, and this occurred for both the APB and the FDI (*excessive* neuroplasticity) - Healthy subjects = slight increase in MEP, only in the APB (specific neuroplasticity) - Conclusion: *neuroplasticity is non-specific and elevated* in dystonia

Sensory reorganization - study on sensory discrimination retraining (Byl 2000)

- Sensory discrimination retraining protocol was intense = 1-1.5 hours of PT, 1-2x/week with HEP (1-2 hours/day) - Activities included identifying sensory stimulation on skin w/ varying textures, objects/designs drawn on hand/fingers, Braille, shapes pressed on skin, dominos with eyes closed, identifying matched pairs of objects - Good outcomes: 11/12 patients returned to work

Sensory tricks - mechanism

- Sensory input temporarily disrupts the dystonic posture ("sensory dependent symptoms") - Sensory/tactile input alleviates decending output from the brain to the muscle - May or may not know that they have one (present in ~70%) - Examples 1. Touching side of face/neck to alleviate cervical dystonia 2. Touching the thighs in leg dystonia

Abnormal sensory processing - brain activity (fMRI study)

- Task = passive arm movements + fMRI - Findings = people with cervical dystonia show *overactivation* in the cingulate cortex, postcentral gyrus, and Cb compared to control - Conclusion = dystonia involves *elevated cortical response to sensory stimulus* (excessive neural activity in multiple regions of the brain)

Dystonia intervention approaches - *compensatory strategies*

- Use of compensatory or new movement strategies to replace the abnormal motor program and improve motor function - In some cases, adaptive equipment is essential to decrease disability - Examples: 1. Voice software to decrease writing duration (hand dystonia) 2. Pen grips to augment tactile input 3. Neck collar to limit motion and provide sensory input 4. Extra mirrors in car (minimizes need to rotate neck)

Dystonia - general patient presentation

- VERY heterogeneous - May or may not have dx of dystonia - Often referred to PT/OT w/ dx of muscle strain, repetitive strain injury due to lack of diagnostic tests - Refer to a neurologist if they have no had a workup yet

Motor characteristics of dystonia - *alleviating maneuvers* (sensory tricks)

- Voluntary actions that specifically correct the abnormal posture or alleviate the dystonic movements - Typically, simple movements or tactile stimulation to body region affected - E.g. Touching chin or raising arms to help straighten neck

Dystonia treatments - pharmacological (3)

1. *Anticholinergics* = first-line Tx to reduce ACh tone, DA in striatum, and D1 pathway drive (less involuntary movements); however results in global deficits long-term 2. *Botulinum toxin* = "gold standard" first-line; blocks ACh in muscle --> less muscle tone; temporary paralysis method 3. *Baclofen* = GABA agonist to reduce alpha motor neuron excitability

Hyperkinetic movement disorders (7 examples)

1. *Dystonia* 2. Tremors 3. Chorea 4. Tics 5. Myoclonus 6. Stereotypies 7. Restless leg syndrome - Note that dystonia can present with other movement disorders

Dystonia - naming (type) based on affected body region (3)

1. *Focal dystonia* = isolated to 1 area or group of muscles - Spasmodic torticollis/cervical dystonia (neck dystonia) - Focal hand dystonia (e.g. musician's dystonia or writers cramp) - Spasmodic dysphonia (vocal dystonia) 2. *Segmental dystonia* = one body region or segment - Arm or leg dystonia (runner's dystonia) - Cervical and oromandibular dystonia 3. *Generalized dystonia* = legs and at least 1 other body region - Whole body or hemi

Dystonia - 2 classifications

1. *Primary dystonia* = dystonia is the only clinical feature - *Slow onset* (weeks or months) - Idiopathic / many genetic links - Environmental / personal factors? 2. *Secondary dystonia* = symptom 2' to brain damage from a specific cause or injury - *Sudden onset* (days) - CP, stroke, brain injury, PD, Wilson's, Huntington's, MS - Side effects of medications (psychoactive)

Dystonia - patient description examples (3)

1. A never-ending Charlie horse 2. Nagging, pulling, twisting in all directions 3. Like tightness in your neck after sleeping wrong

Dystonia pathophysiology - neurologic characteristics (3)

1. Abnormal sensorimotor processing 2. Deficient inhibitory systems 3. Abnormal/excessive plasticity

Prudente et al. 2017 - Movement practice has been found to improve... (4)

1. Disease severity 2. Quality of life 3. Motor performance 4. Need for botox (decreased cost and pain)

Dystonia pathophysiology - deficient inhibitory systems (4 components)

1. Impaired spinal cord reflexes 2. Increased brainstem excitability 3. Decreased intracortical inhibition in M1 4. Abnormal transcollosal inhibition - Reduced inhibition at 3 levels (cx, brainstem, spinal) --> *excessive cortical resources used* - Results in poor control over motor output and neuroplasticity - Note: excitatory pathways generally unaffected

Dystonia - unique exam findings (3)

1. Involuntary contractions, often *intensified with volitional* movement 2. Task specific or postural specific 3. Sensory trick (+/-)

Dystonia treatment - categories of intervention approaches (5)

1. Movement practice 2. Sensory reorganization 3. Normalization of muscle activity with external techniques 4. ROM/strength/manual therapy 5. Compensatory strategies

Prudente et al. 2017 - rehab intervention classifications (6)

1. Movement practice 2. Training with constraint 3. Sensory reorganization 4. Normalization of muscle activity with external techniques 5. Neuromodulation with training 6. Compensatory strategies Same as presented in lecture except added 2 and 5 and does not include ROM/strength/MT

Dystonia - lifelong management (5 principles)

1. PT for long duration = graded exposure to respect symptoms, be creative 2. Chronic pain - educate on pain neuroscience and secondary complications from dystonia 3. Ongoing intervals of treatment - weekly to monthly, then only if flare up (billing considerations), time with botox schedule, patient preference, functional gain > pain loss 4. Encourage exploration of other health professions - massage, chiropractic, acupuncture 5. Document muscles affected and communicate them to physician injecting botox

Prudente et al. 2017 - conclusions (2)

1. Presents novel approach to classify studies of rehabilitation in focal dystonias based on the theoretical basis of intervention 2. The proposed classification system will move toward a unified theoretical understanding of rehab interventions in dystonia, and assist in providing recommendations for clinical applications and future investigations

Outcome measures for dystonia (4 examples)

1. ROM - how much muscle tension is restricting motion 2. COPM (Canadian Occupational Performance Measure) 3. NDI (cervical dystonia) 4. *Hypertonicity Assessment Tool (HAT)* = delineates dystonia from spasticity and rigidity

Motor learning principles important to movement practice for dystonia (5)

1. Salience = meaningful 2. Comfort/feasibility = depending of level of pain / symptom (don't want to flare up dystonic movements) 3. Graded exposure = increase demand, progressive load 4. Repetition = daily practice, sufficient to induce neuroplasticity 5. Feedback = do not overload the patient early on with feedback and encourage self-evaluation

Neurologic characterstics of dystonia - abnormal sensorimotor processing (3 components)

1. Sensory discrimination is reduced 2. Somatosensory mapping is disorganized 3. Elevated cortical activity in response to stimuli

Abnormal/excessive plasticity - how does maladaptive plasticity occur? (4 "steps")

1. Skilled motor practice 2. Excessive connections / heightened potentiation - Due to reduced levels of *GABA*, which has been shown to decrease during learning and allow for neuroplasticity --> lacking inhibition to control proper timing/amount of plasticity 3. Inability to weaken existing associations 4. Maladaptive cortical reorganization

Dystonia - patient characteristics (5)

1. Soreness/pain 2. Muscle spasms or cramps 3. MSK deformities (if dystonia has gone on long enough --> contracture and/or bony deformities) 4. Tremor often present 5. May have personal factors: - Highly repetitive work activities or postures - Poor stress management - Poor physical fitness - Decreased social interaction due to self-consciousness regarding symptoms

Prudente et al. 2017 - purpose

1. To categorize rehab interventions based upon the common underlying theoretical basis of different approaches (propose a classification system for rehab approaches --> help direct future clinical applications and research) 2. To determine the level of evidence for each category of intervention

How does dystonia lead to MSK dysfunctions?

Dystonia -> muscle tension -> contracture -> MSK dysfunction

Dystonia treatments - antidepressants?

Extremely common

Dystonia treatment - driven by ___

GOALS - Prioritize goals that are challenging, meaningful, and achievable that will improve QOL - Find out what activities are affected and ask them what they want to be able to do (list and rate current function to monitor change over time) - Tx should focus on ALL aspects of the person; do not get hung up on specific motor impairments (e.g. ROM, strength) because there's a chance that may not improve to the degree we expect or anticipate - Concentrate on achieving ONE goal at a time - *PT cannot CURE dystonia, but we can help decrease pain and improve function*

Dystonia treatment - education (goal)

Help them understand the heterogeneity of the disorder

Dystonia - goal of initial evaluation

Identify the *type of dystonia*, based on... - Onset: sudden (secondary) vs. slow (primary) - Ask about recent injury or family hx: head/spine injury (secondary) vs. family history of movement disorder (primary) - Localize muscles affected via palpation, checking ROM --> name the dystonia (cervical, vocal, facial)

Deficient inhibitory systems - spinal cord

Impaired *reciprocal inhibition* in the spinal cord (reflexes) - Stimulation reduces reflex in controls, but not in dystonia - Spinal cord seems overactive

Dystonia treatments - DBS (4 indications)

Indicated for: 1. Primary dystonia with... 2. Minimal fixed deformities 3. Younger 4. Best for severe generalized cases (less effect in focal dystonia) - Note: unlike PD, the effects of DBS normally take several months to manifest improvements in symptoms

Prudente et al. 2017 - quality of evidence

Low to very low - Evidence for movement practice and neuromodulation + motor training for cervical and hand dystonias were highest

Common regions of MSK dysfunction 2' dystonia, which can be addressed with manual therapy (3)

MSK dysfunction --> provide joint mobilizations as able 1. Thoracic spine, ribs, scapula - trunk or generalized dystonia and cervical dystonia 2. Cervical spine - cervical dystonia 3. TMJ - oromandibular dystonia

Dystonia treatments - medication side effects

Many central side effects - Sedation - Cognitive effects: memory loss, confusion - Insomnia - Dry mouth - Blurry vision - Urinary changes - Dizziness - Coordination

Dystonia vs. pediatric torticollis

NOT related - Pediatric torticollis = related to short musculature and treated w/ stretching - Dystonia = neurologic condition which cannot be stretched or strengthened away (but you can increase movement and reduce pain)

Dystonia vs. spasticity

NOT the same and cannot be treated the same

Cervical dystonia - types (4)

Named for direction of head - *Torticollis* = rotated - *Laterocollis* = to the side - *Retrocollis* = backward (extended) - *Anterocollis* = forward (flexion)

Alternative manual therapy methods (2)

Not strong evidence, but common and anecdotally effective for improving function 1. Mechanical link - vibration triggers healing 2. Craniosacral therapy - based on sutures in skull contracting and relaxing

Prudente et al. 2017 - rehab interventions were classified based on ____

Underlying theoretical basis of approach

Dystonia intervention approaches - *ROM/strength/manual therapy*

Use of classic stretching and strengthening to reduce secondary MSK dysfunction 1. *ROM* = manual stretching and mobilizations - Adapt positions to reduce flare up 2. *Strength* = focus on ANTAGONIST muscles - Isometric initially, then progress 3. *Fitness* = light aerobic activity - Adapt previously enjoyed activities

Dystonia treatments - cannabis?

Yes for symptom reduction, but a cure