MEG contraindications

The signal measured by an MEG system is extremely low (\(10e^{-15}\ T\)), the device is very restrictive with potential artifacts-inducing elements. None of the contraindications listed below can be harmful for the participant or for the device: an MEG is a fully passive device. The contraindications will only impact the signal quality. Thus, if the cohort of participant is limited/rare it is possible to perform the experiment with a reduced signal quality. Depending on the artifact, it might be possible to correct in preprocessing through MaxWell filtering and Spatiotemporal SSS (tSSS).

Tip

MRI compatibility is not equivalent to MEG compatibility. An MRI compatible object might still contain some amount of ferromagnetic materials which do not disqualify it for MRI certification but will induce artifacts on the MEG signal.

Questionnaires for participants

Fillable PDFs in english or french are available below.

English	French

Known contraindications

• pacemaker, or any kind of cardiac stimulator

• insulin pump, bladder neurostimulator, deep-brain neurostimulator, or any kind of implanted device

• cardiac valves, both mechanical or animal

• hearing aid, hearing implant

• joint prosthesis (hip, knee, shoulder, ..)[1]

• neurosurgical clip for brain aneurysm

• orthodontic equipment, dental prosthesis, dental retainer[2]

• sutures with metal wires or staples

• non-removable piercings, ear rings, ..

• tattoos[1]

• permanent makeup and eye makeup[3]

• recent hair color or any kind of hair extensions

• dreadlocks (MEG’s helmet is quite narrow)

• foreign object in the eye

• shrapnel or metal object in the body

• filter in the vena cava to prevent pulmonary embolism

• metal workers or construction workers working with metal[5]

On top of those contraindications, it’s better if the participant:

• comes with clean hair/beard[4]

• was not in an MRI or subject to an MRI-field in the last 2 weeks[5]

• did not have any recent surgeries[5]

[1] (1,2)

May depend on material and localization. It’s safer to avoid including participants with this contraindication, but depending on participant and lab availability, he/she can come for a brief screening test in the lab (requires about 10 minutes) before booking the actual MEG slot. Tattoos below the elbow do not usually created artifacts.

[2]

Any kind of dental work should be aoivded. However, some dental work/dental retainers are compatible. Depending on participant and lab availability, he/she can come for a brief screening test in the lab (requires about 10 minutes) before booking the actual MEG slot.

[3]

Makeup remover is available at the lab, but it is safer and faster if the participant arrives without any makeup.

[4]

A sink, showerhead and hairdryer are available at the lab, but it is safer and faster if the participant comes with clean hair/beard.

[5] (1,2,3)

In case of doubt and depending on participant and lab availability, he/she can comes for a brief screening test in the lab (requires about 10 minutes) before booking the actual MEG slot.