@jazz, I really dislike the terms "habituation of reaction" and "habituation of perception" because strictly in a scientific sense habituation is 100% about reaction and has nothing to do with perception. That said, Dr, Jastreboff coined the two terms in describing what happens in TRT ... and you asked a TRT question. So I am going to explain the terms specifically as used in TRT.
The simplest way to look at habituation of reaction (or "Hr") is a decrease in the degree to which you react to your tinnitus over time. It is important to understand that Hr is a process. The farther along Hr proceeds, the less bothersome your tinnitus is and the less distress it causes you. It is also important to understand that we are not talking about your tinnitus being less loud or less pitchy. We are talking about your reacting less to your tinnitus regardless of how loud or pitchy it might be.
Now the brain is very "busy" organ. Even when you are at rest, your brain is very busy. And in order to function effectively, your brain must prioritize; it simply cannot attend to all the stimuli it encounters at any given time throughout the day. That's why - until I mention it - you have been unaware of the pressure that the chair you are sitting in right now has been exerting against your buttocks, and it is why within a few moments you will be unaware of it again ... unless you check. So the brain puts stimuli to which you react less way down on its list of priorities. Dr. Jastreboff calls this process habituation of perception (or "Hp").
The whole idea here is that the less you react to your tinnitus over time (Hr), the less you will perceive it over time (Hp) unless you purposely check. And again, this phenomenon holds true regardless of how loud or pitchy your tinnitus might be. That is why, for instance, a person can have a cuckoo clock in the house or a gtrandfather clock in the house but only rarely be aware of the sounds they make. Or why somebody can live near railroad tracks yet largely be unaware of the trains.
It is not true that (as you suggest in your post) Hr must be "achieved" before Hp can be achieved. They are
processes and not
states. The less one reacts to his or her tinnitus over time, the less one will tend to perceive it - unless he or she purposely checks.
Hope this helps more than confuses.
Stephen Nagler