nrTMS for depression

Applications: Psychiatry, neuropsychology

Non-invasive therapy for medication resistant patients

PET  imaging  studies   in   patients   diagnosed   with   major   depressive   disorder (MDD) have shown lower metabolism, compared to  controls,  in  their  left dorsolateral prefrontal cortex (DLPFC)  regions,  which  supports  the  concept  of  using  TMS  as  a  therapy  to  increase  the  excitability of the left DLPFC.

 

Navigation enables accurate targeting of the DLPFC.  Without neuronavigation, research shows that the correct area is only targeted in approximately 30% of patients. Studies show that without navigation, treatments are unintentionally being delivered on average 2 cm posterior to the DLPFC

 

Nexstim NBT® System with SmartFocus® nTMS uses advanced algorithms based on mathematical modelling, taking  into  account  both  the  shape  and  the  composition of each patient’s individual brain. SmartFocus® nTMS displays the location and orientation of the maximum induced E-field in a 3D rendering, built from the patient’s own MRI  head  scan.  The  multi-sphere  model  has  been  scientifically  validated  to  accurately determine  the  location  and  orientation  of  the  maximum  induced  e-field  in  the  brain  and  hence  to  target  the stimulation  to  the  intended  spot  with  accuracy  in  the  millimetre range. 

July, 2021:

Of the 208 patients who have completed Nexstim SmartFocus® rTMS treatment with Nexstim NBT® system for major depressive disorder (MDD), 50.5% were in remission at end of treatment and 76.0% had obtained a clinical response, compared to recent findings from a multi-centre study that reported 26.5-28.7% remission and 41.5-56.4% clinical response.

How?

  • Similar to EnTMS motor mapping, the patient's resting threshold is determined by targeting the primary motor cortex (usually at 120% of the resting threshold).

  • Nexstim EnTMS enables accurate and precise targeting of the DLPFC without anatomic assumptions.

  • The conventional rTMS protocol involves 10hz bursts of 40 pulses (one burst is 4s duration), with one burst every 30s at an interval of 26s.

  • 3,000 total pulses in a sequence, with total duration between 18-37 minutes.

  • Theta burst protocols can also be enabled however these are not reimbursable by Medicare.

  • Opportunity to align with the Nexstim NBT registry, to collaborate for best-practice techniques and share observations.

Hospital purchase of Nexstim NBT system

In-house:

Referral for patient MRI

Outsourced:

Consultant clinician books appointment with Neuroclast

rTMS conducted by Neuroclast with in-person or remote support from clinician

Data sent to consultant clinician for analysis

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Nexstim's proprietary SmartFocus technology ensures for the most precise dosing of TMS in comparison to non-navigated alternatives. This is not simply 'navigated TMS'; this takes into consideration the 'spread' and 'direction' of the stimulation in consideration of the patient's individual cortical topographic anatomy. As the operator moves, turns or tilts the coil - even slightly - the system shows the updated location, orientation and stimulating E-field data in real time.

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En-TMS conducted by Neuroclast can be included in multiple multi-centre trials throughout Australia. Consent will be sought prior to any data capture, and acquired from the patient, consultant and hospital.

Recommended Reading

  • Fitzgerald & Daskalatis (2013). Repetitive Transcranial Magnetic Stimulation Treatment for Depressive Disorders: A practical guide.