Sleep Disorders

• What is sleep ?

  Specific pattern of brain activity with reduced consiousness and activity
• Techniques used to identify sleep ?


  EEG (brain electrical acitivty) EMG (muscular) and EEG (eye movement)
• Define Wakefulness ?

  • low amplitude + high frequency brain electrical activity
  • important muscle activity
  • important mobility in eye
• Define SWS ?

  • high amplitude + low frequency = slow waves, reflects slowing down of mental
  • reduced muscle activity but persistent residual muscle tone (posture)
  • immobile eye
• Define REM ?

  • Low amplitude + high frequency = a bit similar to wake
  • NO muscle activity = muscle atonia
  • Rapid eye movement
• Techniques to study sleep ?

  • Polysomnography
  • Hypnogramme
• What is the Polysomnography ?


  Assessment and description of each sleep stage using EEG, EMG and EEG + other physiologcial parameters.
• More sleep stages first part of night : then decrease
• Sleep disorders ? (the big 3)


  ● Central origin hypersomnias

  ● Insomnias

  ● Parasomnias
• Excessive daytime sleepiness ?

  inability to stay awake during the day resulting in episodes of uncontrollable need to sleep or unintentional sleep attacks.
• What are the two categories of central origin hypersomnias ?

  • idiopathic hypersomnias = “consumed” by sleep
  • narcolepsy =“haunted” by sleep
• The amount of sleep in a narcoleptic person is the same as the normal person
• Symptoms of NT1 ?

  • EDS
  • Fragmentation of sleep
  • Hypnagogic hallucinations
  • Sleep paralysis
  • Cataplexy = loss of muscle tone = this is pathognomonic
• Pathognomonic means an important unique symptom
• Cataplexy ?

  • Loss muscle tone

  ● Feeling extreme weakness after strong positive emotion

  ● Episodes can be partial or total

  ● Start from the head then the neck and the upper body

  ● Short
• How to diagnose NT1 ?

  • MSLT
  • CSF ORX
• What MSLT in NT1 person shows you ?

  • fragmented = shorter cycles
  • EDS during day
  • At least 2 SOREMPs = sleep onset REM period, basically when you go directly to REM sleep and not to NREM stage 1
  • Mean sleep latency = 8 min
• NT1 : ORX measurements in CSF ?

  inferior to 110 pg/mL
• Whats the main cause NT1 ?

  Loss ORX neurons
• What are the 3 possible animal models for NT1 ?

  • ORX KO mice = ORX gene
  • ORX Rc KO mice = ORX signaling
  • ORX ataxin3 & DTA mice = ORX neurons
• The 2 genetic predispositions of NT1 ?

  • HLA allele MOSTLY
  • TRA gene = polymorphism of T cells receptors
• The environemental factors of NT1 ?


  Airway infections such as bacterial + H1N1 virus
• CD8 T cells are cytotoxic, meaning they can directly destroy target cells. The hypothesis is that in NT1, due to inflammation, neurons start to express MHC class I molecules.
• 3 types of pharmacological TTT ?

  • stimulants
  • cataplexy management = antidepressant
  • improve sleep quality = sodium oxybate
• Short naps can be refreshing for NT1 patients and can restore wakefulness
• does ORX cross the BBB ?

  YES
• Are there currently trials for TTT in NT1 ?

  Yes, a potential ORX replacement therapy
• NT2 symptoms ?

  • EDS
  • Hypnagogic = when asleep and Hypnopompic = when awake, hallucination
  • Short restorative naps
  • Sleep paralysis
  • Distrubed night sleep
• Does NT2 cause ORX neuron loss ?

  NO
• NT2 : ORX measurements in CSF ?

  superior to 110 pg/mL
• What MSLT in NT2 person shows you ?

  It is the same as NT1
• NT2 TTT ?


  Same as NT1 such as sodium oxybate and modafinil
• What is idiopathic hypersomnia ?

  People are "consumned" by sleep, they have incresed need for sleep
• Idiopathic hypersomnia symptoms ?

  • EDS and exessive daily sleep > 10h
  • Sleep drunkenness
  • Cognitive distrubances
  • long NON-restorative naps
• Does Idiopathic hypersomnias cause ORX neuron loss ?

  NO
• Idiopathic hypersomnia diagnosis ?

  • Total sleep/24 more than 660 minutes
  • MSLT : sleep latency less 8 min but MORE than 2 SOREMPS
  • ORX CSF levels higher than 110 pg/ml
• The diagnostic criteria for all central origin hypersomnia include the Multiple Sleep Latency Test (MSLT), orexin (ORX) levels in cerebrospinal fluid (CSF), and excessive daytime sleepiness (EDS).
• What is insomnia ?

  Sleep deficency because of issues falling asleep, sleep continuity and poor quality.
• What are the 3 family of factors of chronic insomnias ?

  • predisposing = biological & psy
  • precipitating = events
  • perpetuating = inadequate sleep habits
• What is the main hypothesis for insomnia ?

  Physiological hyperarousal : because of increased heart rate, metabolic rate activity of the pituitary - adrenal axis, increased fast frequencies