a flickr image.
A new study by Swedish researchers asserts that cognitive speed declines much earlier and more rapidly than previously had been understood by most scientists, and faster than perceptual acuity and vocabulary.
The Gothenburg University study led by Valgeir Thorvaldsson followed the subjects over a 30 year period. Of three topical areas - cognitive speed, perceptual ability, and verbal ability - cognitive speed was the mental factor that was impacted the earliest.
In Jensen's estimation, this was defined as 'nerve conduction velocity.' One might conclude based on the plentiful supporting results that this ability is the most reliable indicator of impending cognitive impairment.