AAII is reporting individual investor bullish sentiment declined a sizable 16.8 percentage points to 21.7% in the week ending 8/7/2019. This is the lowest level since bullish sentiment reached 20.9% on December 13, 2018, a market bottom in the fourth quarter 2018 pullback. The low level of of bullish sentiment certainly classifies this as an extreme level.
Neutral sentiment fell 7.4 percentage points resulting in bearish sentiment spiking higher to 48.2%. This results in the bull/bear spread coming in at an extreme -26.5 as seen in the below chart. At this level of spread, historically, market lows have occurred at or near these levels. In summary, investor sentiment certainly appears to be at extreme bearish levels.