Can someone explain me why a a patient with a sensorineuronal or nerve deafness has a normal rinne test ?

i think it it has nothing to do here wz Renin level ...coz it it is congenital heart disease ..due to defect in cardiac Na and K channels .

i will try to explain in a very simple way and i hope this will help you...

so....we have 2 types of 'hearing':
1.through air conduction(AC): external-media-internal ear and then reaches CN 8
2.through bone conduction(BC): mastoid process-temporal bone-reaches CN 8;

in a normal patient AC>BC and this is a normal Rinne test;
if somebody has a hearing deficit, the problem could be anywhere from external to internal ear or could affect CN 8; if we 'split' the problem in this 2 situations, than it is easy to understand how Rinne test will be:

a.problem with the AC.....this means anywhere from external ear to internal ear but with a NORMAL CN 8!!! in this situation the sound which reaches CN 8 is smaller than a normal one through AC but the patient has a normal BC(BC 'skips' all the AC pathway); from this point of view it is quite logic that BC should be greater than AC which means an abnormal Rinne test;
b.normal AC but CN 8 is affected.....this means the AC will carry a normal sound but the brain will not receive the same ammount of informations because CN 8 is affected; from this point of wiev AC is normal; next: BC is also normal but because CN 8 can't deliver the right ammount of sound received through BC, the brain will not 'hear' normal; so, BC is also normal; from what i said first: if AC>BC, this is a normal Rinne test; this is the case where nerve deafness or sensorineuronal deafness occure and if you understand what i just wrote, you will figure it out why in ANY CN 8 pathology, a Rinne test will be normal(AC>BC) but in a AC problem with a normal CN8, Rinne test is abnormal(BC>AC)....

I hope this will help you....good luck!