Hyperalgesia is the increased response to a nociceptive stimulus, while allodynia refers to a response to a non-nociceptive stimulus.
In simple terms we could say that in one case what hurts, hurts more and in the other, what did not hurt, starts hurting.
The instruments for measuring hyperalgesia are many, but the most traditional ones are Tail Flick and Plantar Test for thermal hyperalgesia and Analgesy-meter (paw pressure) or PAM for mechanical hyperalgesia.
The instruments for measuring allodynia the Von Frey hairs, Electronic Von Frey or the Dynamic Plantar Aesthesiometer are the classic devices.
