Fundamentals of Sleep Medicine E-Book

Richard B. Berry

• Editore: Saunders
• Anno: 2011
• ISBN:
  9781455711239
• Argomento: Medicine
• Categoria: Ear, Nose & Throat Medicine

Written by Richard Berry, MD, author of the popular Sleep Medicine Pearls, Fundamentals of Sleep Medicine is a concise, clinically focused alternative to larger sleep medicine references. A recipient of the 2010 AASM Excellence in Education award, Dr. Berry is exceptionally well qualified to distill today's most essential sleep medicine know-how in a way that is fast and easy to access and apply in your practice.

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Chapter 1

Sleep Stages and Basic Sleep Monitoring

Chapter Points

• In the EEG or EOG derivation G₁-G₂, an upward deflection in the tracing is noted if input G₁ becomes negative with respect to input G₂ (negative upward polarity).

• To differentiate whether alpha waves or sleep spindles are present, change to a 10-second window and count the individual deflections in one second (see Fig. 1–3).

• K complexes and slow waves have the greatest amplitude in frontal derivations. Sleep spindles and saw-tooth waves have the greatest amplitude in central derivations.

• Alpha activity is any wave form with a frequency of 8 to 13 Hz. Alpha rhythm has a frequency of 8 to 13 Hz, is most prominent in the occipital derivations, and is enhanced by eye closure and attenuated by eye opening.

• The recommended EEG derivations are F₄-M₁, C₄-M₁, and O₂-M₁.

• The recommended EOG derivations are E₁-M₂ and E₂-M₂. Both eye electrodes are referred to a common mastoid electrode M₂.

• The front of the eye (cornea) is positive with respect to the back of the eye (retina). If the eyes move toward E₁-M₂ and away from E₂-M₂, this causes a downward deflection in E₁-M₂ and an upward deflection in E₂-M₂.

• In the recommended EOG derivations, eye movements result in out-of-phase deflections. K complexes result in in-phase deflections.

• In stage R, the chin EMG amplitude is equal to or lower than the lowest level in NREM sleep. The chin EMG activity can reach the REM level during NREM sleep. Transitions from NREM to stage R are not always associated with a drop in chin activity. Chin EMG activity is useful in differentiating stage R from stage W with the eyes open (REMs present).

Sleep is divided into non–rapid eye movement (NREM) and rapid eye movement (REM) sleep. Sleep staging is based on electroencephalographic (EEG), electro-oculographic (EOG), and submental (chin) electromyographic (EMG) criteria. EOG (eye movement recording) and chin EMG recordings are used to detect REM sleep, which is characterized by REMs and reduced muscle tone. Since 1968, sleep was usually staged according to A Manual of Standardized Terminology, Techniques and Scoring System for Sleep Stages of Human Subjects, edited by Rechtschaffen and Kales (R&K).¹ In the R&K scoring manual,¹ NREM sleep was divided into sleep stages 1, 2, 3, and 4. REM sleep was referred to as stage REM. Sleep stage nomenclature has changed following the publication of the American Academy of Sleep Medicine (AASM) Manual for the Scoring of Sleep and Associated Events (hereafter referred to as the AASM scoring manual).² The new nomenclature was introduced to denote sleep stages defined by new criteria. The old and new nomenclatures are shown in Table 1–1. Stages 3 and 4 are combined into stage N3.

TABLE 1–1

Sleep Stage Nomenclature

	R&K	AASM
Wake	Stage W	Stage W
NREM	Stage 1 Stage 2 Stage 3 Stage 4	Stage N1 Stage N2 Stage N3
REM	Stage REM	Stage R

AASM = American Academy of Sleep Medicine²; NREM = non–rapid eye movement; R&K = Rechtschaffen and Kales A¹; REM = rapid eye movement; stages 3 and 4 are combined into stage N3.

Today, digital polysomnography (sleep recording) has virtually replaced recording on paper. However, previously sleep recording was performed with polygraphs using ink writing pens with ...