Problems with unilateral electrode placement

[cloz]

Hi there,
I have several patients with unilateral electrode placements with some on the left and some on the right. During the manual reconstruction step, I set the hemisphere to the side of the electrode. However, regardless of if i select “left only” or “right only”, the red box indicating which side to click on comes up on the right-hand side of the window. is that supposed to happen?

During the electrode localization refinement, I’ll be able to see the electrode in approximately the correct spot and I’ll be able to move it up and down using the arrow keys, however as soon as I try to adjust at individual contacts (e.g. 0 or 3), the contact will light up, but my key presses do not respond. In the mat lab window, this error comes up.

Index exceeds matrix dimensions.

Error in ea_manualreconstruction>updatescene (line 386)
    coordhandle=mplot(selectrode);

Error in ea_manualreconstruction>ea_keystr (line 211)
            updatescene([],[],mcfig);
 
Error while evaluating Figure KeyPressFcn

Index exceeds matrix dimensions.

Error in ea_manualreconstruction>selectelectrode (line 1067)
set(mplot(selectrode),'MarkerEdgeColor','y');
 
Error using ea_manualreconstruction>selectelectrode (line 1066)
Error while evaluating ToggleTool OnCallback

Index exceeds matrix dimensions.

I am then able to save the electrode (even though it’s not in the precisely correct spot). During the lead group, these unilateral electrodes fail. I get a message along the lines of “patient x is unable to be processed”. Am I missing something from the instructions perhaps? Thanks for any help!

[andreashorn]

Hi cloz,

unfortunately, unilateral leads are not really reported, especially not in Lead group. Sorry about that, we just never had a real project with them so there was no need to support them up until now.
I fear you need to write custom code for the group level stuff.
On single subjects, in the rare unilateral patients I visualized so far, I usually just place two leads in and ignore one of them (deselect in 3D viewer). But I fear – depending on what you aim to do in lead group, it won’t really work.

Best, Andy

[cloz]

Hi Andy,
Oh okay, no problem. We may end up excluding these unilateral patients from our analysis. But thanks for the info and the tips.

Chris

[Author]

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