Usefulness of Vocal Fatigue Index for Hypertension of Extrinsic Laryngeal Muscles

Background and Objectives This study compares Vocal Fatigue Index (VFI) scores according to the presence or absence of external laryngeal tension in hyperfunctional voice disorder. And through this, it is to confirm the usefulness of VFI to hypertension of extrinsic laryngeal muscles.Materials and Method The subjects were 61 female diagnosed with hyperfunctional voice disorder (hypertension group 41, non-hypertension group 20). The author palpated extrinsic laryngeal muscles for evaluation of hypertension and classified them as the presence or absence. The voice measurements were jitter, shimmer, Korean-Voice Handicap Index-10 (K-VHI-10), and Korean-Vocal Fatigue Index (K-VFI). The voice compared were according to the diagnosis and presence of hypertension only for patients with hyperfunctional voice disorder.Results As a result of comparing the voice measurement according to the presence or absence of hypertension, there was no significant difference in the acoustic variables, K-VHI-10 and K-VFI-Total, K-VFI-Fatigue. Whereas, K-VFI-Physical (p=0.006) and K-VFI-Rest (p=0.022) were significantly higher in the hypertension group.Conclusion These results indicate that the hypertension group has more physical discomfort and less voice recovery than the group without hypertension. It means that K-VFI can measure the physical discomfort and limitations of voice recovery due to hypertension of the external laryngeal muscle. The VFI can be used as one of the methods to evaluate the hypertension of the external laryngeal muscle in Hyperfunctional voice disorder.

A dual larynx motor networks hypothesis

Humans are vocal modulators par excellence. This ability is supported in part by the dual representation of the laryngeal muscles in the motor cortex. Movement, however, is not the product of motor cortex alone but of a broader motor network. This network consists of brain regions that contain somatotopic maps that parallel the organization in motor cortex. We therefore present a novel hypothesis that the dual laryngeal representation is repeated throughout the broader motor network. In support of the hypothesis, we review existing literature that demonstrates the existence of network-wide somatotopy and present initial evidence for the hypothesis' plausibility. Understanding how this uniquely human phenotype in motor cortex interacts with broader brain networks is an important step toward understanding how humans evolved the ability to speak. We further suggest that this system may provide a means to study how individual components of the nervous system evolved within the context of neuronal networks. This article is part of the theme issue ‘Voice modulation: from origin and mechanism to social impact (Part I)’.

Botulinum toxin treatment for adductor spasmodic dysphonia with EMG and endoscopic guidance

Background & Objective: Spasmodic dysphonia is idiopathic focal dystonia characterized by irregular contractions or postural disorders of the laryngeal muscles, resulting in abnormal speech. Progress in laryngoscopy has resulted in development of a precise technique of botulinum toxin (BTX) injection into the thyroarytenoid muscle under visual control. Methods: We used EMG and endoscopic guidance for BTX injection in adductor spasmodic dysphonia (AdSD). Results: Thirty eight patients with AdSD were injected with BTX in 84 treatment sessions. The voice handicap index (VHI) level of the patients were: severe (73.8%), moderate (26.2%) and mild (none). The average VHI score was 74.6 points. After 8 weeks of BTX treatment, the VHI level was: Severe (3.6%), moderate (10.8%), and mild (85.7%). The average VHI score was 27.7 points. The average values of jitter, shimmer and harmonic to noice ratio (HNR) improved statistically (p < 0.05). The incidence of side effects were: breathiness (17.9%), choking (15.5%); hoarseness (8.5%), and dysphagia (4.7%). Conclusions: Injection of BTX under both EMG and laryngoscopy guidance for treatment of adductor spasmodic dysphonia is an effective and safe treatment.

Respiration

This chapter discusses the respiratory system of giraffes. The respiratory system supplies oxygen, removes of carbon dioxide and produces the airflow needed to make sounds. Giraffes do not have the velocity of airflow through the airways to vibrate vocal cords sufficiently to generate sounds able to be heard by humans but can produce sounds able to be heard by giraffes. Air reaches alveoli for gas exchange through a long trachea, which is relatively narrow (~4 cm in diameter). Dead space volume is large. A short trunk and rigid chest wall reduce the capacity of the thorax and consequently lung volume is small. Respiratory rate is low (~10 min-1), but tidal volume is relatively big, and alveolar ventilation rate (VA; ~60 L min-1) delivers sufficient air despite the large dead space volume. Laryngeal muscles act to prevent food from entering the trachea a process controlled by the (short) superior and (long) inferior (recurrent) laryngeal nerves. Air that has been delivered to alveoli comes into contact with pulmonary artery blood (=cardiac output, Q; ~40 L min-1). The VA: Q ratio is ~1.5 (cf 0.8 in humans). Gas exchange occurs by diffusion. The surface area for diffusion is related to the number of alveoli which increase in number during growth from ~1 billion in a newborn giraffe to 11 billion in an adult. Gas carriage of oxygen and carbon dioxide is a function of erythrocytes which are small (MCV = 12 fL) but numerous (12 × 1012 L-1) and each liter of blood contains ~150 g of hemoglobin.

A dual larynx motor networks hypothesis

Humans are vocal modulators par excellence. This ability is supported in part by the dual representation of the laryngeal muscles in the motor cortex. Movement, however, is not the product of motor cortex alone but of a broader motor network. This network consists of brain regions which contain somatotopic maps that parallel the organisation in motor cortex. We therefore present a novel hypothesis that the dual laryngeal representation is repeated throughout the broader motor network. In support of the hypothesis we review existing literature which demonstrates the existence of network-wide somatotopy, and present initial evidence for the hypothesis’ plausibility. Understanding how this uniquely human phenotype in motor cortex interacts with broader brain networks is an important step toward understanding how humans evolved the ability to speak. We further suggest that this system may provide a means to study how individual components of the nervous system evolved within the context of neuronal networks.

Dysphagia in a Young Man

This case report presents oropharyngeal dysphagia due to oromandibular and cervical dystonia, a rare consequence of aseptic meningitis. A 19-year-old male who was diagnosed with aseptic meningitis visited the rehabilitation outpatient clinic for a sense of foreign body in his throat and odynophagia. Repetitive involuntary movements of his facial, tongue, and laryngeal muscles accompanied by lateroanterior torticollis were observed. Videofluoroscopic swallowing study showed inefficient bolus formation due to repetitive rolling of his tongue and vallecular stasis without penetration or aspiration. Dysphagia and odynophagia had brought the patient significant weight loss and frustration. We provided swallowing training to improve the efficiency and safety of swallowing. The patient’s symptoms improved gradually along with body weight gain and emotional stability. Acute-onset oropharyngeal dysphagia is devastating for young adults. A multidisciplinary approach is mandatory for optimal outcome. We share our experience as a team work and emphasize the rehabilitation aspect.