Everybody must do an internship, regardless of specialty. Now some specialites have it nice, such as the primary care and general surgery guys as their internship years are fast tracked and count toward both internship and first year of residency. This is not the case for most other specialties. You have to do pretty much a transitional year, medicine year, or surgery year before entering most other specialties. Its just part of the game and there is no way around it.
To sit for board certification in neurology, you must do an internship. YOu must do at least six months of internal medicine in that internship (not all wards, can be IM specialties, ICU, CCU, etc.). Don't try to avoid it, as it will be useful to you. Neurology is a medicine specialty, if you admit people to your service as a neurology resident you are expected to manage blood sugars, blood pressures, fluids, electrolytes, etc. Your internship year will be most helpful for preparing you for this. Ultimately, you have to take with USMLE3 or COMPLEX 3 depending on your medical degree, your intenship year will prepare you for this.
Simply put, there is no fast track into neurology like there is for family medicine or general surgery, etc. Do an internship, get it over with, learn, move onto neurology residency. Four years isn't so bad.