Despite many attempts, we do not yet know how to answer the question exhaustively and adequately: What is common Danish stød phonetically? Specifically, is there an underlying physiological constancy behind the considerable acoustic variability? And is there a common denominator to the different acoustic manifestations that might explain their perceptual equivalence? Systematic acoustic, physiological, and perceptual investigations of common Danish stød now span (a little more than) three quarters of a century. This is a review of that research, to determine what may be considered established phonetic facts about common Danish stød and the open questions that remain for future research.

The effect of sulcus vocalis on vocal folds function is investigated. A type II sulcus vocalis is defined, parameterized and incorporated into a three-dimensional, fully coupled finite element model of vocal folds and laryngeal airway. The proposed Fluid-Structure Interaction (FSI) model is utilized in computational fluid dynamics, Arbitrary Lagrangian-Eulerian (ALE), incompressible continuity and Navier-Stokes equations and in a structure range of a three-layer elastic linear model. Flow parameters, vibration behavior and glottal jet aerodynamics of healthy and patient vocal folds models are compared with each other. Flow visualization is utilized to characterize Coanda effect and three dimensionality of flow patterns. The vibration frequency of vocal folds having sulcus vocalis decreases in comparison with that of healthy ones. Upon increasing the volume flux in the sulcus vocalis model, the non-periodic and disordered behavior of it is visible for patient vocal folds. Underlying mechanisms for the observed changes, possible implications for treatments of sulcus vocalis and human perfect voice production are also discussed.

Speaking is a very complex process resulting from the interaction between the air flow along the larynx and the vibrating structure of the vocal folds. Sulcus is a disease missing layers in the vocal folds result in cracks resulting in some disorders in producing sounds. Sulcus and its effects on the vocal cord vibrations are numerically studied for the first time in this paper. An ideal model of healthy vocal folds and Sulcus vocalis has been two-dimensionally defined and the finite element model of vocal folds is solved in a fully coupled form. The proposed calculative model was used in a fluid range of the computational fluid dynamics, arbitrary Lagrangian-Eulerian (ALE), incompressible continuity and Navier-Stokes equations and in a structure range of a three-layer elastic linear model. Self-excited oscillations were presented for vocal folds among type II patients and compared with healthy models. Responses were qualitatively and quantitatively studied. The healthy model was compared with numerical and empirical results. In addition, the effects of the disease on the flow parameters and the vibration frequency of the vocal folds were studied. According to the simulated model, the oscillation frequency decreased 25% and the average and instantaneous volume flux significantly increased compared to healthy samples. Results may help present a guideline for surgery and subsequently evaluate patients’ improvement.

A 51-year-old woman complained of hoarseness of two years duration. The patient's past medical history was significant for autoimmunological hepatitis and arthritis for which she had not received treatment. Laryngoscopy and laryngeal stroboscopy revealed ‘bamboo joint-like nodules’ on both true vocal folds. These nodules resembled rheumatoid nodules and were suggestive of a collagen disease. Previous reports have documented that the treatment for such conditions related to collagen diseases is surgical resection. However, we initially attempted to treat the laryngeal lesions systemically with prednisolone. The hoarseness and the bamboo-like nodules disappeared six months after the treatment. Furthermore, the liver function test returned to normal and arthritis completely resolved. Based on our patient's response to this treatment, we diagnosed atypical-SLE and a lupus laryngitis. This case suggests that studies of the larynx may be helpful in the early diagnosis of collagan diseases and that such conditions may respond to systemic treatment.

A prospective study was designed to compare the effects on voice capacities after either suspension microlaryngoscopic surgery or indirect microlaryngostroboscopic surgery. Patients where the clinical diagnosis 'dysphonia due to a benign lesion of the vocal fold' was made, and who could be operated in either way, entered the study. Post-operative voice evaluation was performed on 21 patients after suspension microlaryngoscopic or indirect microlaryngostroboscopic surgery. The long-term voice results following indirect microlaryngostroboscopic surgery and suspension microlaryngoscopic surgery demonstrate a statistically significant improvement for the maximum intensity, maximum dynamic intensity range, dynamic intensity range at habitual speaking pitch, and melodic pitch range. In selected cases indirect microlaryngostroboscopic surgery offers a very good functional result.