Parkinson's Disease Flashcards
What is PD?
- Degenerative disorder of CNS
- Result of decreased stimulation of motor cortex by basal ganglia
- Chronic & progressive
What does PD cause?
- Decreased speed & amplitude of movement
- Tremor
- Changes in muscle tone & posture
- Inability to perform simultaneous or sequential motor tasks
What is the aetiology of PD?
- Likely induced by environmental factors in people with genetic predisposition
- 2-14 fold increase in incidence in close relatives of people with PD
- 1 in 100 people > 65yo
What are the risk factors of PD?
- Positive family history
- Male
- Exposure to pesticides
- Rural living
- Head injury
- Consumption of well water
What are 4 nuclei that make up the basal ganglia?
- Striatum (caudate & putamen)
- Globus pallidus (internus & externus)
- Subthalamic nuclei
- Substantia nigra
What is the role of the basal ganglia?
- Execution of complex motor tasks
- With SMA run well-learned & predictable movement sequences
- Provision of internal cues for starting/stopping movement sequences
- Involved in aspects of memory & cognitive function
- Loss of motor set
What is the pathophysiology of PD?
- Loss of dopaminergic neurons in substantia nigra
- Causes decreased inhibition of globes pallid us & increased inhibition of thalamus (decreased output)
- Presence of Lewy bodies
- Other neurotransmitters thought to be involved
- Still not well understood
What is clinical diagnosis of PD based on?
- Medical history
- Physical examination
- Improvement with dopaminergic treatment
- Long pre-clinical/symptomatic period (many people are far progressed at diagnosis)
What is used in the medical management of PD?
Levodopa:
- Metabolic precursor to dopamine
- Initially effectively controls motor problems
- Associated with significant side effects (nausea, mood/behavioural issues, orthostatic hypotension)
COMPT inhibitors used to maintain therapeutic doses for longer
What are the long term effects (5-7 yrs) of levodopa (L dopa)?
- Dyskinesia (impairment of voluntary movement, central writhing movement)
- On-off phenomenon (on phase after medication causes peak in motor performance; as medication wears off causes decrease in quality of movement)
What does the surgical management of PD include?
- Pallidotomy (removal of globus pallidus, which removes inhibition of thalamus)
- Deep brain stimulation of globus pallidus internus or sub-thalamic nuclei - shown to improve QOL significantly in advanced PD
What are the primary impairments in PD?
- Bradykinesia (slowness of movement)
- Hypokinesia (decreased amplitude of movement)
- Akinesia (difficulty initiating movement e.g. freezing)
- Tremor (resting, rhythmical, consistent)
- Rigidity (centrally mediated, in both directions)
- Balance impairment
What are the secondary impairments in PD?
- Dyskinesia
- Disuse weakness
- Flexed posture
What are the common activity limitations in PD?
- Turning in bed
- Sitting up from lying
- Standing up
- Reduced speed & balance, freezing & falling during walking/turning in standing
- R&M esp handwriting
What should the assessment of PD include?
- History
- Observation
- Assessment & measurement of impairments/activity limitations
What should be included in the history assessment of PD?
- Time since diagnosis
- Medications (what, when, how long, fluctuations, side effects)
- Movement problems, including falls
- Other problems associated with PD
- Previous/current physio intervention
What should observation assessment of PD include?
- Turning in bed
- Supine to sitting over side of bed
- STS
- Walking
- 360 deg turn in standing
- R&M
What are some of the balance tests used when assessing PD?
- Tandem stance
- Single leg stance
- Functional reach
- Shoulder tug (Pastor’s test)
- Mini Best test
What are some of the other impairments that should be assessed in PD?
- ROM
- Strength
- Respiratory function (flexed posture)
- Fitness
- Falls diary
- Dyskinesia diary
What are some of the impairment measures used for PD?
- Unified Parkinson’s disease rating scale (UPDRS)
- Hoen & Yahr scale (0-5)
- Freezing of gait questionnaire
- Falls efficiency scale
- Berg balance scale
- Mini Best test
What are some of the activity limitation measures used for PD?
- 10MWT
- 6MWT
- TUG
- 10 x STS
- Time taken to turn in bed
- Time taken to sit over side of bed
- Number steps taken when turning 360 degrees
- Handwriting sample & spiral test
What are the characteristics of hypokinesia?
- Most common impairment in PD
- Most pronounced in complex sequential or simultaneous tasks
- Bilateral
What is hypokinesia caused by?
- Reduction in initial agonist burst at each joint
- Contributed to by weakness, tremor & rigidity
- Correlated with reduced UL & LL ROM, poor ADLs and life satisfaction index
What is the effect of hypokinesia on gait?
- Reduced stride length in walking & turning
- Caused by decreased amplitude of movement at all joints
- Results in reduced gait speed
- Exacerbated by dual tasking
- Causes falls risk
What are the intervention strategies for hypokinesia?
- Attentional, visual & auditory cueing (normalises stride length)
- Dual task training
How do cueing strategies work?
- External stimuli cause alternative circuits in the brain to engage in accomplishing the tasks
- Avoids the defective basal ganglia circuitry
What did Spaulding et al 2013 find regarding cueing for hypokinesia during walking?
- Systematic review
- Examined effects of visual & auditory cues on stride length, speed & cadence
- Both had a clinically significant effect on increasing stride length
- Auditory cues also had a significant effect on increasing speed & cadence
- CIs: Train with visual & auditory cues
How did the study by Canning 2005 look at the effect of instructions on walking performance in PD?
- Compared effect of specific instructions on walking performance
1. Comfortable walking alone
2. Comfortable walking carrying a tray & glasses without instructions
3. As above with instructions to concentrate on big steps
4. As above with instructions to concentrate on the tray
What were the results of the study by Canning 2005 looking at the effect of instructions on walking performance?
- Prioritising attention to step length normalised walking speed & stride, task was 96% error free
- Prioritising attention to tray significantly decreased walking performance
- CIs: Train dual tasking while concentrating on main activity
What did Brauer & Morris 2010 find regarding dual task training in PD?
- Examined effect of dual task training on step length in mild/mod PD
- 20 mins walking training with variety of cognitive tasks
- 10MWT completed before & after with 6 different dual tasks
- Step length improved significantly in all but 1 dual task conditions
- Walking speed increased in 3/6 dual task conditions
What is akinesia?
- Difficulty initiating or continuing movements
- AKA freezing
- Often preceded by festination (rapid reduction in step length, increased cadence e.g. when approaching doorway)
When does akinesia occur?
- Initiating movement
- During turning
- Performing concurrent tasks
- End dose
- Narrow doorways
- Cluttered/busy environment
What are the intervention strategies for akinesia?
- Self-generated cues
- External auditory & visual cues
- Modifying the environment
What did Nieuwboer et al 2007 find in the RESCUE trial examining akinesia in gait?
- Patients chose auditory, somatosensory or visual cues
- Training 30 mins 3 x per week for 3 weeks in home
- Showed reduction on freezing but no carryover at 6 weeks
What did Brichetto et al 2006 find regarding the effect of cues on akinesia?
- Looked at use of auditory & cognitive cues
- Training involved gait practice in variety of environments using auditory then cognitive strategies
- 45 mins 3 x week for 6 weeks
- Significant improvement in FOG questionnaire & QOL immediately after training & at 1 month
What is occurring in the basal ganglia at rest?
- Only postural control
- Thalamus is exciting the cortex
- Basal ganglia globus pallidus is inhibiting the thalamus to prevent movement
What happens in the basal ganglia in response to an external stimulus?
- Cortex excites striatum
- Causes inhibitory effect on globus pallidus which stops inhibition of thalamus
- Thalamus excites cortex for movement tasks
What happens in the basal ganglia as external stimuli increases?
- Cortex firing rate increases allowing for bigger/faster movements
- BG allows you to direct thoughts to different motor programs (movement, talking, mood etc) at the same time
Of the primary impairments in PD, which impairments are the main cause of activity limitation?
- Bradykinesia
- Hypokinesa
- Akinesa
- Balance impairment
What did Dibble et al 2006 find regarding eccentric strength training in PD?
- RCT comparing standard care vs 12 week high intensity eccentric strength training
- Looked at quads volume, strength & mobility
- Strength training group has a 6% increase in quads volume, an increase in strength & improved 6MWT
What were the specific treatment recommendations Keus et al compared in 2007?
- Cueing strategies to improve gait
- Cognitive movement strategies to improve transfers
- Exercises to improve balance
- Training of joint mobility & muscle power to improve physical capacity
What did Keus et al 2007 find regarding specific treatment recommendations for PD?
- PD patients with 1+ falls in last 12 months are likely to fall again in next 3 months
- Falls occur during transfers & FOG
- Cueing strategies may improve gait
- Cognitive movement strategies may improve transfers
- Balance exercises are more effective when combined with LL strengthening
- Training of joint mobility & muscle power may improve ADLs
What did the first experiment by Kamsma et al 1994 find regarding kinesiology of turning in bed & rising from a chair?
- Compared PD patients with students & elderly
- Turning in bed: PD patients used a variety of supports, movement was fragmented & slower
- Rising from a chair: PD patients were non-fluent, required more effort
What did the second experiment by Kamsma et al 1994 find?
- Provided new motor strategies for turning in bed & rising from a chair
- All pts received L-dopa
- 6 x 1hr sessions
- Errors decreased after 6 sessions
- Errors were made in execution of movement
- Significant improvement in performance in short term, even in severely affected pts
What were the motor strategies used in the second experiment by Kamsma et al 1994?
- Movement decided into small steps (starting distally)
- Steps were sequential
- Executed under conscious control
- Pause between steps
- Each step concluded with a stable position for the next to begin
- Axial components limited
