Source : Webster's Revised Unabridged Dictionary (1913)

Impersonally \Im*per"son*al*ly\, adv.
   In an impersonal manner.

Source : WordNet®

impersonally
     adv 1: without warmth; "he treated his patients impersonally" [ant:
             {personally}]
     2: in an impersonal manner; "when I told him about Russ I found
        it difficult to speak impersonally"