title: Long-Term Cognitive Impairment in Kleine-Levin Syndrome.
abstract: OBJECTIVE
  In Kleine-Levin syndrome (KLS), episodes of hypersomnia, cognitive, and behavioral disturbances alternate with asymptomatic periods. Because 50% of patients report decreased academic performances, we evaluated their cognitive status during asymptomatic periods, determinants of deficits, and changes during follow-up.
  
  
  METHODS
  The cognitive assessment during asymptomatic periods in all consecutive patients with typical KLS and healthy controls included the non-verbal intelligence quotient (Raven Progressive Matrices), the Trail Making Test, the Stroop Color-Word Test, the Wechsler Memory Test, verbal fluencies, the Free and Cued Learning Memory Test, and the Rey-Osterreith Complex Figure. Cognitive status was reevaluated after 0.5 to 2 y in 44 patients.
  
  
  RESULTS
  At baseline, compared with the 42 controls, the 122 patients with KLS exhibited lower non-verbal intelligence quotient, speed of processing, attention, and reduced retrieval strategies in episodic memory. Higher episode frequency, shorter episode duration, shorter time since last episode, deeper sleep, and megaphagia during episodes predicted impaired memory. The visuoconstructional abilities and non-verbal memory were intact. After a mean follow-up of 1.7 ± 1.0 y, the episode frequency decreased from 4.6 ± 4.8 to 1.7 ± 1.9/y. The logical reasoning and attention improved, the processing speed remained low, and the retrieval strategies in verbal memory further worsened.
  
  
  CONCLUSIONS
  In this field study, one-third of patients with KLS have long-term cognitive deficits affecting retrieval and processing speed. Cognitive function should be systematically tested in patients with KLS, which appears important to help patients in their academic studies.
authors.affiliation: Sorbonne University, UPMC Univ Paris 06, IHU neuroscience, Reference Center for Kleine-Levin Syndrome of the Pitié-Salpêtrière University Hospital, Assistance Publique - Hôpitaux de Paris, France.|Sleep Disorder Unit, Reference Center for Kleine-Levin Syndrome of the Pitié-Salpêtrière University Hospital, Assistance Publique - Hôpitaux de Paris, France.|Brain Research Institute (CRICM), Inserm UMR-S975, CNRS UMR7225, Paris, France.
authors.forename: Ginevra
authors.initials: G
authors.lastname: Uguccioni
authors.affiliation: Sorbonne University, UPMC Univ Paris 06, IHU neuroscience, Reference Center for Kleine-Levin Syndrome of the Pitié-Salpêtrière University Hospital, Assistance Publique - Hôpitaux de Paris, France.|Sleep Disorder Unit, Reference Center for Kleine-Levin Syndrome of the Pitié-Salpêtrière University Hospital, Assistance Publique - Hôpitaux de Paris, France.|Brain Research Institute (CRICM), Inserm UMR-S975, CNRS UMR7225, Paris, France.
authors.forename: Sophie
authors.initials: S
authors.lastname: Lavault
authors.affiliation: Sleep Disorder Unit, Reference Center for Kleine-Levin Syndrome of the Pitié-Salpêtrière University Hospital, Assistance Publique - Hôpitaux de Paris, France.
authors.forename: Charlotte
authors.initials: C
authors.lastname: Chaumereuil
authors.affiliation: Biostatistics Department, Reference Center for Kleine-Levin Syndrome of the Pitié-Salpêtrière University Hospital, Assistance Publique - Hôpitaux de Paris, France.
authors.forename: Jean-Louis
authors.initials: JL
authors.lastname: Golmard
authors.affiliation: Département de Psychologie, Université du Québec, Montréal, Canada.
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Gagnon
authors.affiliation: Sorbonne University, UPMC Univ Paris 06, IHU neuroscience, Reference Center for Kleine-Levin Syndrome of the Pitié-Salpêtrière University Hospital, Assistance Publique - Hôpitaux de Paris, France.|Sleep Disorder Unit, Reference Center for Kleine-Levin Syndrome of the Pitié-Salpêtrière University Hospital, Assistance Publique - Hôpitaux de Paris, France.|Brain Research Institute (CRICM), Inserm UMR-S975, CNRS UMR7225, Paris, France.|INSERM and AP-HP, CIC-1421, Pitié-Salpêtrière University Hospital, F-75013, Paris, France.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Arnulf
mesh_terms: D000293:Adolescent; D001288:Attention; D016022:Case-Control Studies; D003071:Cognition; D003072:Cognition Disorders / Q000150:complications* / Q000175:diagnosis / Q000523:psychology*; D006970:Disorders of Excessive Somnolence / Q000150:complications; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007361:Intelligence Tests; D017593:Kleine-Levin Syndrome / Q000150:complications* / Q000523:psychology*; D008297:Male; D008569:Memory Disorders / Q000150:complications / Q000175:diagnosis / Q000523:psychology; D061212:Memory, Episodic; D008570:Memory, Short-Term; D009483:Neuropsychological Tests; D011930:Reaction Time; D013997:Time Factors; D055815:Young Adult
keywords: Kleine-Levin syndrome; episodic verbal memory; processing speed; retrieval