Spiked helmets with chain-mail curtains over the neck and eyes were used in Indian Rajput mail armor of the 18th Century, and Persian mail armor of the early 19th. But I don't feel sure they were deflectors since their thin spikes would also seem to catch inward strokes by an enemy blade. At the least it would knock the helmet askew.
It seems to me that Near Eastern armies were changing over to guns as European armies had, and that their elaborate armors were likewise being relegated to "full dress". In this way, helmet spikes simply looked more fearsome than functional and also made the Near Eastern warrior look taller, as shakos did the European soldier.
from military uniform historian John Mollo's book Military Fashion (New York: G.P. Putnam's Sons, 1972), page 133:
"...a great wave of romanticism engulfed the field of military costume [in Europe after 1830], taking several different directions at the same time. In the early 1840s there appeared the celebrated Pickelhaube, or spiked helmet. This helmet was almost certainly designed by Nicholas I of Russia, and the story goes that Frederick William IV saw a prototype lying on [Nicholas'] desk, copied the idea, and got it out faster than the procrastinating Russians. A romanticized version of an ancient Slav helmet was already appearing on coins and medals during the reign of Alexander I, but Nicholas was the first to have the brainwave of adapting existing Russian cuirassier helmets by simply removing the horsehair crest and replacing it with a grenade finial."
I have heard that the pointed cloth helmet (shlem) worn by Soviet troops up to World War II, later called the budyennovka, was based on the Pickelhaube. German prisoners reportedly designed it to wear in their Russian captivity, and made it look like their spiked helmet of prewar years. Does anyone know if this has any truth to it?
Many of these PoWs returned to Germany in 1918 "infected" with Bolshevism and filled the armed ranks of German communists. The Red Army may have adopted their pointed cloth helmet as a symbol of solidarity, since Lenin wanted to foment a Red revolution in Germany and fought the 1920 war in Poland to reach that country. If the Pickelhaube really was the basis for the shlem, that would be quite a turnaround of symbolism.