Page 69 - GTM-3-4

Global Translational Medicine New neck examination for sleep apnea

been found to occur internationally at the rate of 12% of Disorders Questionnaire (SDQ)-2, the NoSAS, and
15
14
the general population for all types of sleep-disordered the OSA50. There have also been several critical reviews
16
breathing (SDB, minor to severe) and at the rate of 5% for of these and other questionnaires 17-19 focusing on their
moderate to severe OSA. While these authors noted some sensitivity to the presence of SDB and their specificity
3
racial, ethnic, and geographic differences, they showed in excluding other diagnoses. This is usually reported
that the condition is found in all countries and populations as a receiver operating characteristics (ROC) analysis
at approximately the same rate, attesting to its biological using the NPSG as the gold standard. In summary, very
etiology. In most cases, its etiology is attributed to reversible few questionnaires have a sensitivity over 70% with a
obstruction of the “soft” airway, that is, the airway superior simultaneous specificity of over 60%, and therefore, their
to the vocal cords. OSA has strong associations with positive and negative predictive values leave much to be
pathological daytime sleepiness, hypertension, type 2 desired, considering the modest fraction of the population
diabetes, and myocardial infarction. The most common who suffer OSA or milder SDB. While questionnaires
4
and least invasive treatment is continuous positive airway can be suggestive of SDB, they fall considerably short of
pressure (CPAP) for OSA, but various otolaryngological a diagnosis on which treatment decisions could be made.
surgeries that produce various outcomes against SDB have
been proposed. 5 Physical examinations that have been used to predict
the presence of SDB include: body weight and body
Since 1976, OSA has been reliably identified through an mass index (BMI); neck circumference; and oral cavity
NPSG. Recently, milder forms of SDB such as hypopneas examination rating scales such as the modified Mallampati
and the even milder respiratory event-related arousals (MM) soft palate position scale (scored 1 – 4) and the
(RERAs) have been identified and found to cause sleep Friedman tonsil size (FTS) scale (scored 0 – 4 with “0”
20
disruption similar to OSA in many patients, although indicating that tonsils have been removed). As these two
6
they cause less hypoxia. Due to the diverse definitions of tests have been performed in different ways by different
RERAs, we did not assess them in this study. clinicians, Yu and Rosen summarized the accepted way
21
For many years, the NPSG has been the only definitive to perform them and also reviewed individual papers
way to identify SDB. However, in North America and and meta-analyses that showed a modest but significant
Europe, despite most major hospitals having a sleep prediction of OSA by both techniques. In brief, the MM
laboratory, it is still a scarce resource in rural and isolated palate assessment is performed with the mouth wide open
areas. In many other countries, NPSG is essentially and the tongue protruded, while in the FTS, the tonsil size
unavailable. While NPSG is still regarded as the “gold is rated with the tongue at rest in the open mouth. Yu and
standard” for diagnosis of SDB, it is also a labor-intensive Rosen concluded that there was still debate about the utility
procedure that presently costs upwards of US$ 1000 per of these two rating scales due to their relatively modest
night and even existing sleep disorders centers have long correlations with polysomnographic OSA diagnosis,
7
waiting lists. higher correlations in men compared to women, and low
inter-rater reliability (kappa = 0.36).
For this reason, other methods that enable instant and
economical identification of SDB have been proposed. Confusion in the literature arises due to a second
In this context, a simple screening test that could easily rating scale proposed by Friedman, the “Friedman
detect the characteristics of SDB is required so that the tongue position” (FTP) scale, which to simplify, is an MM
patient could be referred for more rigorous diagnosis examination with the tongue in the rest position. The FTP
and treatment. Such screening tests fall into one of four was not employed in the present study. Therefore, in the
categories: (i) patient self-report questionnaires (see present paper, MM refers exclusively to assessment of palate
8,9
below); (ii) simple physical examination methods; position and visibility, while the FTS refers exclusively to
(iii) portable “wearable” electronic devices 10,11 that tonsil size.
essentially perform some or all of the functions of an It can be seen from the above discussion that almost
NPSG; and (iv) high-technology devices such as skull all non-NPSG diagnostic methods are essentially
imaging through computed tomography (CT) scan, observational and correlational in nature. Only modern
magnetic resonance imaging (MRI), cranio-facial X-ray, “wearable” electronics that replicate some or all of the
or ultrasound evaluation of the upper airway, although the functions of an NPSG are truly diagnostic, yet they
latter equipment is not the focus of the present paper. come at a significant cost and their results require expert
Numerous questionnaires have been validated against interpretation. Even the gold standard NPSG is only a
NPSG for the identification of OSA. These include: STOP- snapshot of a single night of sleep, which may or may not
Bang, Berlin Questionnaire, SDB subscale of the Sleep include supine rapid eye-movement (REM) sleep – where
12
13
Volume 3 Issue 4 (2024) 2 doi: 10.36922/gtm.4548