Tested with different helmets at different difficulty settings. No change occurred with any of the following permutations:
(Helmet Type), (Difficulty)
ODST (Base), Easy
01000100011000010111011001100101
SPARTAN III BIOS S56.7854.3354-DKW
ODST (Base), Normal
01000100011000010111011001100101
SPARTAN III BIOS S56.7854.3354-DKW
ODST (Base), Heroic
01000100011000010111011001100101
SPARTAN III BIOS S56.7854.3354-DKW
ODST (Base), Legendary
01000100011000010111011001100101
SPARTAN III BIOS S56.7854.3354-DKW
ODST (UA/CNM), Legendary
01000100011000010111011001100101
SPARTAN III BIOS S56.7854.3354-DKW
Mark V [B] (Base), Legendary
01000100011000010111011001100101
SPARTAN III BIOS S56.7854.3354-DKW
Mark V [B] (UA), Legendary
01000100011000010111011001100101
SPARTAN III BIOS S56.7854.3354-DKW
Mark V [B] (UA/HUL), Legendary
01000100011000010111011001100101
SPARTAN III BIOS S56.7854.3354-DKW