The first study aimed at directly assessing
learning capacity after sleep loss was done by
Randazzo and co-workers.96 Sixteen children were
asked to sleep only 5 h for a single night and then
their psychomotor and cognitive performance was
assessed, together with sleep propensity as evaluated
by the MSLT. Tasks measured attention,
vigilance, abstract thinking, memory, learning and
creativity. As a consequence of sleep restriction,
subjects showed shorter sleep latencies and an
impaired performance on verbal creativity (mainly
fluency and flexibility) and on abstract thinking.
Although easier psychomotor tasks as well as
memory and learning tests failed to show differences
after sleep curtailment, it should be pointed
out that scores in the Wisconsin Card Sorting Test
(WCST) were significantly affected, indicating a
difficulty in learning new abstract concepts. The
authors concluded by observing that a moderate
sleep restriction can affect the children’s executive
functions that ‘yenable the individual to engage
in creative, adaptive learning by initiating and
regulating retrieval of knowledge from long-term