A period of hightened sensitivity, is when your senses are more sensible than usual. In
Shift terms, this is an
Attributes Shift.
Note that the "heightened senses" fenomena is something in the scientific world that is considered a characteristics of people with various degrees of
Autism. What actually happens is that it's not the senses themselves that would increase in sensitivity, but rather the neural wiring behind it (brain) that becomes much more sensible to sensory input. It is also indeed characteristic of this Autistic trait to come and go in the same way as therian shifts usually do.
See also