Section IV. Neurostimulation Treatment Flashcards by Rani Ojah

What are the six types of neural stimulation?

Transcranial direct current stimulation
Repetitive transcranial magnetic stimulation
Electroconvulsive therapy
Magnetic seizure therapy
Vagus nerve stimulation
Deep brain stimulation

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For neurostimulation, what acute treatments for MDD are first line?

rTMS
ECT (in some clinical situations)

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For neurostimulation, what acute treatments for MDD are 2nd line?

ECT

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For neurostimulation, what acute treatments for MDD are 3rd line?

tDCS
VNS

** both level 3 evidence

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For neurostimulation, what acute treatments for MDD are 3rd line?

tDCS
VNS

** both level 3 evidence

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What level evidence is there for rTMS for maintenance therapy for MDD?

Level 3

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What level evidence is there for ECT for maintenance therapy for MDD?

Level 1

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For tDCS, what are the two types of stimulation?

Anodal stimulation [increases cortical excitability through depolarization]

Cathodal stimulation [decreases cortical excitability through hyperpolarization

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What is the target for tDCS?

NMDA receptor

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Location of tDCS stimulation?

Over left dorsal lateral prefrontal cortex

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frequency of tDCS treatment?

30 minutes per day for two weeks to see antidepressant effect

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advantages of tDCS [5]

easy to use
Low-cost
Portability/could use at home
Combine with other treatments
Low potential for adverse side effects`

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Side effects of tDCS?

redness of skin at site
itching / burning
tingling
H/A
blurred vision
ringing in ears
illuminated vision
mild euphoria
reduced concentration
insomnia
anxiety

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What is the overall recommendation for transcranial direct current stimulation [tDCS]?

3rd line treatment for MDD, level 2 evidence for acute efficacy with inconsistent results if good for monotherapy or combo therapy

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what are the overall recommendations for rTMS?

1st line for patients who have failed at least 1 antidepressant (** rTMS often added to a pre-existing antidepressant regime)
Level 1 acute efficacy
Level 3 evidence for maintenance
Level 1 for safety and tolerability

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what is rTMS?

Magnetic fields
Electrical currents into neural tissue
Noninvasive
Inductor coil on scalp (placed with MRI guidance)
No anesthesia

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Frequency of rTMS?

Five days per week, however, three times weekly is also effective but with slower improvement

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how many sessions to maximize effect of rTMS?

26-28

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how many sessions are required to declare treatment failure of rTMS?

20 sessions

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What is the intensity, frequency, and site for rTMS?

Stimulate at 110 to 120% of resting motor threshold [70 to 80% for theta-burst stimulation]

Level 1 evidence

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how do you determine stimulus intensity for rTMS?

Stimulus intensity is based on each patient resting motor threshold [RMT] which is the minimum intensity needed to elicit muscle twitches at relaxed upper or lower extremities by visual inspection or electromyography [EMG]

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what is the most common intensity for rTMS?

110% RMT, however, other trials have used 120% RMT

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what is defined as high frequency for rTMS?

High frequency is 5 to 20 Hz which is excitatory

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what is defined as low frequency for rTMS?

Currency is one to 5 Hz which is inhibitory

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what is theta burst stimulation [TBS]?

Delivered at lower intensity [70 to 80% of motor threshold] One to three minutes of stimulation

how effective is our team SS antidepressant therapy for MDD?

- 1st line treatment for MDD - Often prescribed in those with TR MDD - Good efficacy found with high frequency left DLPFC - Good efficacy found with low frequency right DLPFC

True/ False -- Bilateral stimulation has shown superiority over unilateral

FALSE

Without maintenance therapy, what is the percent chance relapse at 6 months?

77% relapse at 6 mos

Which is more effective for patients with MDD with psychosis? ECT or rTMS

ECT

Adverse side effects associated with rTMS:

Scalp pain Transient headaches

Are there absolute contraindications for rTMS? If so, what are they?

1. Cannot use HIGH-frequency rTMS w seizure history ** seizure induction is very low with rTMS (0.01 to 0.1%) 2. Patient cannot have metallic hardware anywhere in their head [cochlear implant, brain stimulator, aneurism clips]

What are the relative contraindications of rTMS?

1. Cardiac pacemaker 2. Implantable defibrillator 3. History of epilepsy 4. Presence of brain lesion [vascular, traumatic, neoplastic, infectious, or metabolic]

What are the clinical indications for ECT [9]?

1. Acute SI 2. Psychotic features 3. TR depression 4. Repeated medication intolerance 5. Catatonic features 6. Prior favourable responses to ECT 7. Rapidly deteriorating physical status 8. During pregnancy 9. Patient preference

What are the relative contraindications [7]?

1. Space occupying cerebral lesion 2. Increased intracranial pressure 3. Recent MRI 4. Recent three roll hemorrhage 5. Unstable vascular aneurysm 6. Pheochromocytoma 7. Class 4 or 5 anaesthesia risk

Why is ECT 2nd line treatment for MDD?

Because of adverse side effects

What is the MOA for ECT?

unknown - but might increase brain derived neurotrophic factor

what are the 4 options for electrode placement?

Bilateral Bitemporal Bifrontal Right Unilateral

What electrode placement is recommended as first line for treatment using ECT for MDD?

Bifrontal Right Unilateral

Why is bitemporal electrode placement 2nd line?

Because of higher rates of short term cognitive adverse effects

What is the treatment session and frequency for ECT?

Between six and 15 sessions deliver 2 to 3 times per week

What is the max number of treatments recommended per week?

What is the response rate for ECT as an acute treatment for MDD?

70 to 80%

is the strongest predictor of non-response to ECT?

Resistance to previous treatments

which demographics present entire response rates to ECT?

Older patients Patients with psychotic features Patients with shorter depression episode duration Patients with less depression severity

When are relapse rates following acute course of ECT highest?

Relapse rates highest 6 months post ECT

By how much do medications reduce relapse in conjunction with maintenance ECT?

Medications reduce relapse rates by almost half

With regard to medications in conjunction with maintenance ECT, what antidepressant should you try?

No evidence to support a specific antidepressant Recommended to use antidepressant that has not been tried before ECT Consider nortriptyline plus lithium Consider venlafaxine plus lithium

what is a common schedule for maintenance ECT?

Weekly x4 weeks Then bi-weekly x8 weeks Then q. monthly

What is the mortality rate with ECT?

Less than one death per 73,440 treatments

what types of cognitive impairment are most commonly reported with ECT?

Transient disorientation [partially due to post active confusion and effects of general anesthesia] Retrograde amnesia Anterograde amnesia

what is retrograde amnesia?

Retrograde amnesia - difficulty recalling information learned before ECT, such as autobiographical memories

what is anterograde amnesia?

Difficulty in retaining learn information after ECT

What electrode placement leads to worsened cognitive impairment post-ECT?

Bitemporal

What electrode placement leads to the least cognitive impairment post-ECT?

Ultra Brief Pulse RUL

What is cognitive impairment with ECT high correlated with?

persistent depressive symptoms

What are the risks of using Li+ with ECT?

May increase cognitive SEs, encephalopathy, and spontaneous seizures

What are the risks of using benzos and/ or anticonvulsants with ECT?

May raise seizure threshold and decrease seizure efficacy

Which anticonvulsant might be least problematic with ECT

lamotrigine

Describe magnetic seizure therapy (MST)

- noninvasive - induces an electromagnetic field in the brain to elicit generalized tonic clonic seizures

Where is the MST coil placed?

at the vertex, directly onto the skull

What is the general frequency of stimulation for MST?

100 Hz

What is the duration of MST stimulation?

10 sec

What level evidence is there for MST to replace ECT?

level 3

Describe vagus nerve stimulation (VNS)

- neurostimulation device originally approved for Tx of drug resistent epilepsy - implantable pulse generator underneath skin - electrode placed in vagus nerve

Stimulation of the vagus nerve stimulates:

nucleus tractus solitarius

What is VNS used to treat?

chronic depression recurrent depressoin Adults who have MDD who have failed 4+ *adequate* antidepressant trials

What is the overall recommendation for VNS in MDD?

3rd line acute tx with level 3 evidence

Adverse effects of VNS?

voice alteration dysnpea pain increased cough

Describe DBS

- invasive neurosurgical procedure with an internal electrode that is connected to an IPG implanted in the chest below right clavicle

Indications for DBS?

- movement disorders (Parkinson's) - "difficult to treat" psychiatric disorders - TR depression

Adverse effects of DBS?

- risks from surgical implantation (IC hemorrhage, wound infection) - psychosis - hypomania - blurred vision - stabismus