title: Free recall of word lists under total sleep deprivation and after recovery sleep.
abstract: OBJECTIVE
  One task that has been used to assess memory effects of prior total sleep deprivation (TSD) is the immediate free recall of word lists; however, results have been mixed. A possible explanation for this is task impurity, since recall of words from different serial positions reflects use of distinct types of memory (last words: short-term memory; first and intermediate words: episodic memory). Here we studied the effects of 2 nights of TSD on immediate free recall of semantically unrelated word lists considering the serial position curve.
  
  
  METHODS
  Random allocation to a 2-night TSD protocol followed by one night of recovery sleep or to a control group.
  
  
  METHODS
  Study conducted under continuous behavioral monitoring.
  
  
  METHODS
  24 young, healthy male volunteers.
  
  
  METHODS
  2 nights of total sleep deprivation (TSD) and one night of recovery sleep.
  
  
  RESULTS
  Participants were shown five 15 unrelated word-lists at baseline, after one and 2 nights of TSD, and after one night of recovery sleep. We also investigated the development of recall strategies (learning) and susceptibility to interference from previous lists. No free recall impairment occurred during TSD, irrespective of serial position. Interference was unchanged. Both groups developed recall strategies, but task learning occurred earlier in controls and was evident in the TSD group only after sleep recovery.
  
  
  CONCLUSIONS
  Prior TSD spared episodic memory, short-term phonological memory, and interference, allowed the development of recall strategies, but may have decreased the advantage of using these strategies, which returned to normal after recovery sleep.
authors.affiliation: Universidade Federal de São Paulo, UNIFESP, São Paulo, Brazil.
authors.forename: Gislaine
authors.initials: G
authors.lastname: de Almeida Valverde Zanini
authors.forename: Sérgio
authors.initials: S
authors.lastname: Tufik
authors.forename: Monica Levy
authors.initials: ML
authors.lastname: Andersen
authors.forename: Raquel Cristina Martins
authors.initials: RC
authors.lastname: da Silva
authors.forename: Orlando Francisco Amodeo
authors.initials: OF
authors.lastname: Bueno
authors.forename: Camila Cruz
authors.initials: CC
authors.lastname: Rodrigues
authors.forename: Sabine
authors.initials: S
authors.lastname: Pompéia
mesh_terms: D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D006801:Humans; D008297:Male; D061212:Memory, Episodic; D008570:Memory, Short-Term; D011939:Mental Recall; D010700:Phonetics; D017286:Polysomnography / Q000379:methods; D012890:Sleep; D012892:Sleep Deprivation / Q000503:physiopathology*; D013647:Task Performance and Analysis; D055815:Young Adult