w11 Flashcards

1
Q

What are the benefits of DBS

A

Reduction In “Off” Severity
Increase In “On” Time
Reduction In Dyskinesia (e.g. tics)
Suppression Of Medication-refractory Tremor
Can treat different areas of the brain with different stimulation

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2
Q

What types of patients are unlikely to respond well to DBS

A

patients who ‘Freeze’
patients with postural instability
patients with gait hesitancy
patients with dysarthria (speech difficulty)

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3
Q

what was DBS initially designed for

A

to treat parkinsons disease, because movement disorder surgeries and drugs were not very effective

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4
Q

What diseases are allowed to be treated with DBS

A
Parkinson’s Disease
Essential Tremor
Dystonia
Obsessive Compulsive Disorder
Epilepsy
Tourettes
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5
Q

what diseases could DBS potentially help with

A

Depression
Pain
Anorexia
Obesity

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6
Q

What type of patient is suited to be treated with DBS

A

optimised pharmacotherapy is not effective or causes complications. medication-related adverse effects compromise quality of life.

diagnoses of idiopathic Parkinson’s disease.

Responsive to Levodopa (at least 30-50% improvement)

No dementia or untreated depression or other psychiatric disease.

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7
Q

what was the purpose of the study by Schupbach et al

A

To assess the effect of subthalamic nucleus (STN) stimulation on the quality of life in patients with at an
earlier stage of Parkinson’s disease (PD) (60 years and below).

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8
Q

What were the outcomes of the study by Schupbach et al

A

Improvement in quality of life (QOL), measured by the
PDQ-39 summary index.

Improvement in motor scores, activities of daily living, levodopa-induced complications, and hours of good mobility, PsychoSocial scores.

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9
Q

what is DBS

A

DBS is a surgical procedure that delivers high-frequency electrical stimulation to precise areas of the
brain that carries the abnormal signals producing the symptoms.

The exact mechanism of deep brain stimulation is unknown

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10
Q

what effect does high-frequency electrical stimulation have on the brain

A

an inhibitory effect, altering the abnormal signals

thereby leading to symptom improvement by restoring the balance of communication within the basal ganglia by delivering electrical pulses to a target nucleus

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11
Q

The location of electrode placement varies based on the illness being treated.

What does stimulating the subthalamic nucleus (STN) or globus pallidus internus (GPi) do

A

helps to restore the normal circuitry of the basal ganglia

targeted for parkinsons disease

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12
Q

what is the basal ganglia

A

a collection of nuclei deep in the white matter of cerebral cortex.

The basal ganglia includes: striatum (caudate, putamen and Globus Pallidus), substantia nigra and subthalamic nucleus.

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13
Q

what is the function of the basal ganglia and cerebellum

A

act to fine tune or modify movement on a minute-to-minute basis.

The balance between these two systems allows for smooth, coordinated movement, and a disturbance in either system will show up as movement disorders.

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14
Q

describe the treatment planning steps for DBS

A

MRI scans of patient. Usually a day or two prior to case. Usually on drug so no movement.

Mounting of headframe. Usually off medication. Morning of case.

CT scan. Defines 3D space.

Image fusion and trajectory planning. Determine Anterior-Posterior (forewords and backwards coordinates), Medial (left and right coordinates) and Vertical (how deep) position, with Ring and Arc (point/angle of entry)

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15
Q

describe the pre-testing operating procedure for DBS

A

patient is on operating table with head frame and Mayfield adaptor

draping is placed around patient to keep sterile

skin flap and burr hole (with cover? to lock and hold DBS lead) is created

Micro Electrode Recording (MER) and trial stimulation

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16
Q

what is Intra-Op testing

A

initial testing of DBS implant

occurs during surgery; patient is awake

performed to observe therapeutic effect of DBS stimulation

17
Q

describe the post-testing operating procedure for DBS

A

Once testing complete, location is confirmed. Implantation of DBS lead – 1st stage. The patient is taken out of the frame and put under a GA for stage 2.

Stage 2 involves the tunnelling of extensions down the side of the neck and making a pocket below the clavicle. Connecting the brain leads to extensions and the extensions to the IPG (pulse generator). Then placing the IPG in the pocket and closing up.

post-DBS lead localisation will confirm placement post-op

18
Q

what are the different components DBS hardware

A

IPG/neurostimulator

lead and electrodes

extension cable

patient programmer

19
Q

what types of batteries are offered for DBS neurostimulators

A

primary cells

rechargable

20
Q

what are the typical program settings for DBS patients

A

monopolar stimulation (one contact)

2.3 volts

60-90 us pulse width

130 (?) Hz

21
Q

what are the different parameters you can adjust for DBS stimulation

A

Electrode(s) On The DBS Leads Selected to Deliver Stimulation (four electrodes total)

Polarity Assignments Of Active Electrodes

Amplitude

Pulse Width

Rate /Frequency

22
Q

what are the different polarity assignments available for DBS electrodes

A

Monopolar 0-

Bipolar adjacent

Bipolar 1 apart

Bipolar 2 apart

23
Q

what research is being performed for DBS

A

closed loop control / automation - need to sense sufficiently robust biomarker

automated titration (different simulations at different areas)

Phase or amplitude triggered therapy

segmented leads - contact shapes that are not fully wrapped around the lead