# Biography of Muscle Tension Dysphonia: A Scoping Review
## 4 Discussion
### Diagnosis  
The principal symptoms of MTD are dysphonia and vocal fatigue. Patients with MTD usually manifest increased phonatory effort, accompanied by a reduction or worsening in voice quality. Some patients have symptoms such as tension, pain in the cervical region, and sensations of itchiness, dryness, irritation, or even the presence of a foreign body in the larynx area. Although the symptoms are always a subjective parameter in the diagnosis, there are some scales that can be used to assess them, such as the Vocal Tract Discomfort scale [75]. VHI results show worse scores in patients with this pathology [32; 76]. Observation of the larynx during phonation is indispensable in the diagnosis. It can rule out an underlying organic pathology or a secondary MTD, and it can determine the type of MTD. Garaycochea [31] discusses the three most frequent laryngoscopic profiles in these patients. Anteroposterior supraglottic contraction involves the reduction in the visibility of the vocal cords (VC) at both their anterior and posterior borders. The reduction in visibility of the posterior border is related to approximation of the artytenoids due to an increase in their rotation. At the anterior level, the increase in tension and increased elevation of the laryngeal musculature produces bowing of the epiglottic petiole towards the laryngeal lumen, which makes it difficult to see the anterior border of the VC, starting with visual obstruction of the anterior commissure [1; 32]. Supraglottic lateral contraction results in reduction in the visibility of the width of the VC. The reduction ranges from visual obstruction of the laryngeal ventricle to complete visual obstruction of the vocal cords by the ventricular bands, (False VC phonation). To date, the muscle structure and innervation of the ventricular bands remain poorly understood and areas of controversy; the same applies to the role of the ventricular bands (VB) in normal phonation and in phonation by people with voice alterations. Posterior glottic gap (PGG) refers to an incomplete closure of the VC at their posterior edge. This originates from an attempted contraction of the lateral and interarytenoid croorytenoid muscle accompanied by insufficient relaxation of the posterior cricoarytenoid muscle [7]. The low incidence of PGG relative to that of supraglottic compression in patients with MTD is attributable to the difficulty, in many cases, of observing PGG when there is concomitant supraglottic compression [31]. There have been different proposals of classification systems based on the laryngoscopic profiles during phonation. The first system was written by Morrison in 1986 [8]. While this initial classification did differentiate patients with MTD from patients with psychogenic functional dysphonia, it has been progressively modified by different authors over the last few years. Sama considers psychogenic functional dysphonia profiles as profiles of MTD and excludes those profiles related to organic lesions [77]. Belafsky excludes the presence of \"bowing\" during phonation because bowing is related to underlying glottic insufficiency and not to hyperfunction [16; 78]. A second scoring system was described by Van Lawrence in 1987 [79], and a third was described by Koufman in 1991 [80]. In 2020, Fernandez et al. [32] published a new classification (Universidad de Navarra) based on subglottal pressure (SgP) values, which has been demonstrated to be related to the degree of anteroposterior (AP) compression (Figure 2). The higher the SgP value, the higher the degree of AP compression. This classification system uses the endoscopic profiles mentioned above and assumes that AP contraction is present. While the classic classifications only allow choosing between one of the phonatory profiles, excluding the other ones, the latest classification proposed by Fernandez et al. is based on a single laryngoscopic profile, but it makes it possible to associate LC or PGG, if present, and provide a more detailed description from the physical examination.