Does this sentence require commas?

[erempa]

EEG done in January of 2007 showed background slurring which is abnormal.

[Anglika]

A comma before "which" is needed, unless it is the slurring itself which is abnormal.

[riverkid]

Originally Posted by erempa

EEG done in January of 2007 showed background slurring which is abnormal.

This seems to be an example of quick notation, similar in nature to a shopping list or a set of reminders. Note the absence of an article before "EEG".

In situations like this we often drop unnecessary things.

[erempa]

So the correct way is

An EEG done in January of 2007 showed background slurring, which is abnormal?


I thought it would be An EEG, done in January of 2007, showed background slurring, which is abnormal.

Erin

[Anglika]

Originally Posted by erempa

So the correct way is

An EEG done in January of 2007 showed background slurring, which is abnormal.


I thought it would be An EEG, done in January of 2007, showed background slurring, which is abnormal.
"
Erin

This is where the context is important.

The first sentence has "done in January of 2007" as an adjectival phrase modifying EEG; the second states than an EEG [that was done in January 2007 ] showed...

Which one is correct will depend on the rest of the report.