This is one of the things that's really nagging at me about this thing. Mr. O'Neill trotted this line out several times in the Q&A without actually defining 'clinically significant'. I've read the pre-study paper on Neuromod's website and as far as I can gather they define 'clinical significance' as an improvement of 7 or more in your THI score. An improvement of 7, or 10 even, doesn't feel that significant to me - the natural fluctuation of the condition will move your THI score up & down by 10-15 points regularly. Let's hope the actual improvement seen leans more towards the 'or more' bit.