Arabic & More Aug 19, 2013:

From the neck up... Refers to the head or brain. But here the speaker does not literally mean he needs a mental health examination or psychological treatment by a doctor. Every now and then he finds it useful to do his own assessment of his attitude and probably other things like his beliefs and behaviors towards others (whatever is mentioned in the video in this regard). It sounds like this is probably a motivational talk, and the speaker is encouraging others to check their own attitudes.