Dream reports from 16 subjects across an experimental night were analyzed using story grammar criteria. Reports from the second half of the night were longer and more complex due to more effective dream production, not better recall. This increase involved better organization of individual stories rather than more stories per time period. The findings raise questions about how dream production is re-triggered during REM sleep and whether themes across stories in a dream are interrelated.
Sleep improves memory retention compared to waking, but the mechanisms remain unclear—whether due to reduced interference, slowed decay, or active consolidation. Recent evidence from dream studies suggests consolidation occurs during sleep: items repeatedly accessed and woven into ongoing dreams are better retained at delayed recall. The authors propose extending these information-processing strategies to sleep-disturbed individuals to examine how sleep disturbances affect memory during sleep.
Dream recall frequency in people with Parkinson's disease is comparable to that of other older adults, but the length and narrative coherence of their dreams vary with their cognitive and language abilities. Fifteen outpatients with idiopathic Parkinson's disease, all treated with L-dopa and without psychiatric symptoms, were awakened from REM sleep to report dreams. Thirteen provided at least one dream, yielding a 71.4% recall rate. Longer and more story-like dream reports were associated with higher cognitive functioning and, partly, better language comprehension, but not with age, illness duration, or L-dopa dose.