Treating Speech Language Pathologies Assignment

Treating Speech Language Pathologies Assignment Treating Speech Language Pathologies Assignment Written reflexion: After reading chapter 13 in our textbook, reflect on the role of a speech-language pathologist with clients who are diagnosed with disorders such as paradoxical vocal fold motion/vocal cord dysfunction, irritable larynx syndrome, and/or chronic refractory cough. Why and how do SLPs see/treat these patients? Please cite at least 2 scholarly research articles in addition to your textbook. When appropriate you should cite references in APA style, 6th edition. Use both in text citations and bibliography at the end of an entry. Your submission should be 2-3 pages double spaced. ORDER NOW FOR CUSTOMIZED AND ORIGINAL ESSAY PAPERS attachment_1 attachment_2 Written Reflection #2 and #3 Rubric . Treating Speech Language Pathologies Assignment Please keep in mind that if you do not submit anything, you will receive a 0 for these assignments. Any submitted assignment will receive a minimum grade of 14 points out of 35 points possible. Treating Speech Language Pathologies Assignment Criteria Below Expectations Basic Proficient Exceeds Expectations Critical Thinking 4 Points Rudimentary and superficial; little consideration, analysis, or synthesis; little or no connections with any other material or off topic 6 Points Information is thin and common place; attempts made at consideration, analysis, or synthesis; connections are limited, vague generalities are made 8 Points Substantial information; evidence of consideration, analysis and synthesis; general connections are made, but are sometimes unclear or obvious 10 Points Rich in content; insightful considerations, analysis, and synthesis, with clear connections made to real-life situations or to previous content Personal Reflection and Creativity 4 Points Lack of connection to personal life or attempt to develop creative ideas 6 Points Little evidence of personal connection; connections need further explanation 8 Points Connects ideas and thoughts to personal life; evidence of personal connection to learning and community with creative ideas 10 Points Reflection is high quality, consisting of personal reflections that connect between real-life, learning, and course content Grammar, Style, and Structure 4 Points Obvious grammatical or stylistic errors; errors impact the structure and make content difficult to read 6 Points Obvious grammatical or stylistic errors; errors sometimes interfere with content 8 Points Few grammatical or stylistic error, minimal structure concerns 10 Points An occasional grammatical or stylistic error, no writing structure concerns References and Citations 2 Points Lacks in-text citations and reference section at the end. 3 Points Lacks in-text citations or reference section at the end. 4 Points Few errors in APA style in-text citations or references at the end. 5 Points Includes correct in-text citations as well as a reference section at the end in APA style – 6th edition. ORDER NOW FOR CUSTOMIZED AND ORIGINAL ESSAY PAPERS CHAPTER 13- LARYNGEAL REFLEXES This chapter describes how the body uses sensory information to produce reflex actions, specifically in the larynx. A reflex is an involuntary, stereotypical motor (muscle) response that occurs from a defined stimulus (Pitts, 2014). By definition these actions can and do occur during sleep, while unconscious, and/or while anesthetized. The larynx is capable of a variety of reflexes due to the density and types of sensory receptors. Sensory Receptors The larynx is innervated by many types of sensory receptors also known as afferents. The criteria used to categorize sensory receptors are based upon: a) location of the nerve ending (terminal) in the tissue, b) stimulus response, and/or c) the elicited reflex response. Free Nerve Ending Receptors Free nerve endings are receptors located in the superficial layers of the skin and in deep tis- sue and visceral organs. There are two types of receptors: C fibers, which are unmyelinated, smaller in diameter and slower conducting (Figure 13–1), and Aä “a delta,” which are myelinated and have fast conductance velocity. These receptors respond to different types of stimuli, such as mechanical, chemical, pain (nociceptive) and temperature. Mechanoreceptors are stimulated by distention or deformation caused by vibration, touch and pressure. Chemoreceptors detect substances and chemicals via smell, taste, etc. Thermal receptors detect changes in temperature. Nociceptors are stimulated by tissue damage, or pain. Stimulation of laryngeal TRPV1 C-fibers by capsaicin triggers can trigger apnea (breath holding), bronchoconstriction (closing of the bronchi), and cough (Liu et al., 2015). One C fiber example is TRPV1 (transient receptor potential cation channel sub- family V member 1) which responds to capsaicin (main ingredient in chili peppers that serves as an airway irritant). TRPV1 is also classified as a thermal receptor, specifically to increases in temperature. When eaten, capsaicin stimulates TRPV1 producing a hot or burning sensation, classifying TRPV1 as a Figure 13–1. The left image depicts free nerve endings which are small and unmyelinated in the epidermis with the root in the dermis layer of skin. Epidermis is the outer layer of skin, dermis is the middle layer of skin, and hypodermis is the inner most layer of skin. The right image is a muscle spindle. The muscle spindle afferent are large Interarytenoid afferent nerve fibers that wrap around the center of the muscle spindle and synapse on the alpha motor neuron. As the muscle stretches/ contracts, the capsule round the muscle stretches/contracts with the muscle. This sends information to the brain about the length of the muscle. chemoreceptor. When capsaicin is in contact with skin, it elicits a burning sensation, classifying TRPV1 as a nociceptor as well. This burning sensation is identified as slow pain, which stimulates unmyelinated C fibers, and thus why it is called “hot sauce”! Cough can be stimulated by rapidly adapting receptors, RARs (Aä), and C-fibers in the laryngeal and tracheal mucosa that terminate on the second-order neurons in the nucleus tractus solitarius (NTS) and then project to the pontine and medullary respiratory neuron populations (Canning, 2008). TRPM8 (transient receptor potential cation channel mlastain-8) is expressed in both unmyelinated C-fibers and myelinated Aä rapid adapting receptors. It is a type of Ca2+ permanent, nonselective cation channel that is expressed at the terminals of laryngeal afferents. Menthol is a naturally occurring compound that gives substances a minty smell and flavor (used in gum, cough drops, cigarettes, etc.) that stimulates TRPM8 classifying it as a chemoreceptor. One of the major effects of menthol when applied to the skin or a mucosal surface is the cause of a sensation of coolness and stimulates and sensitizes sensory thermal cold fiber receptors. It is shown that menthol suppresses the enhanced laryngeal reflex activity and suppresses laryngeal C-fiber hypersensitivity to cigarette smoke (Liu et al., 2015). RARs are believed to induce cough via sensory pathway. C fibers, which central pathways inhibit cough, may stimulate cough peripherally by causing release of sensory neuropeptides that activate RARs (Dicpinigaitis, 2003). CHAPTER 13 Laryngeal Reflexes 427 Mechanoreceptors are Aä myelinated fibers, and either adapt slow (slowly adapting receptors, SAR) or fast (rapidly adapting receptors, RAR) to a repetitive mechanical stimulation. SARs fire when the stimulus is present, continuous, and RARs only fire at a rapid change. When the stimulus is continuous, the RARs rearrange their inner structure to adapt to the stimulus. These receptors lack the capacity to discriminate noxious (painful) stimuli and do not respond to chemical stimuli. Pulses of air to the hypopharyngeal and laryngeal mucosa, which is innervated by the internal branch of the superior laryngeal nerve, elicit laryngeal adductor reflex (LAR), or the closure of the glottis. This assesses laryngopharyngeal sensation used to assess dysphagia (Aviv et al., 2002). Intrafusal fibers are skeletal muscle fibers that serve as specialized sensory organs. They detect the amount and rate of change in length of a muscle. Extrafusal fibers are standard skeletal muscle fibers that are innervated by the alpha motor neuron. They generate tension by con- tracting and allow for skeletal movement. Treating Speech Language Pathologies Assignment Encapsulated Nerve Endings Muscles Spindles A muscle spindle (see Figure 13–1), com- prised of 8 to 10 intrafusal fibers arranged in parallel with extrafusal fibers, are attached to the origin and insertion tendons. Large Interarytenoid afferent nerve fibers are wrapped around the center of the muscle spindle, and synapse on the alpha motor neuron. The stretch of the muscle deforms the intrafusal fibers and initiates action potentials. The action potential is initiated by activating mechanical-gated ion channels in the afferent axons that are coiled around the muscle spindle. This action allows a muscle to be excited or inhibited by the muscle spindle. Thyroarytenoid muscle (TA) is the principal component of the vocal fold. It is broken into two distinct compartments, vocalis, which is involved in phonation, and muscularis, vocal fold adduction. The vocalis muscle can be further broken down into superior, which contains more connective tis- sue, and inferior. The muscle spindles in the TA are much shorter, narrower and contain fewer intrafusal fibers compared to muscle spindles in a limb. Muscle spindles in the TA are most concentrated in the superior vocalis, supporting the hypothesis that the function of this is more distinct than the other areas of the TA. The presence of both muscle spindles and slow fibers in the superior vocalis indicate that its primary role is to maintain posture or perform delicate and finely controlled movements for voice (Thach, 2001). There has been debate as to the nature and/or presence of muscle spindle afferents in the intrinsic muscles of the larynx (for sum- mary see Baken and Noback [1971]). It is obvious that there are structures (especially in the TA) that look identical to muscle spindles found in weight-bearing muscles, but upon closer inspection, these structures do have different properties. It is expected that future research will provide additional information about these specialized afferents, and their impact on voice and speech production. Treating Speech Language Pathologies Assignment Golgi Tendon Organs Golgi tendon organs (GTO) are encapsulated afferent nerve ending located at the junction of a muscle and tendon. It is innervated by a single group Ib sensory axon. Unlike muscle spindles, GTO are in parallel with extrafusal 428 Voice Disorders muscle fibers. When a muscle is passively stretched, most of the change in length occurs in the muscle fibers; but when a muscle actively contracts, the force directly acts on the ten- don. GTOs are highly sensitive to increases in muscle tension caused by muscle contraction, but unlike muscle spindles, insensitive to passive stretch. GTOs are likely very important for ballistic behaviors such as cough, throat clearing, or sneeze. Passive stretching is when an external force, such as gravity, acts upon the limb or muscle. Treating Speech Language Pathologies Assignment Pathway of Sensory Information Mechanoreceptors and chemoreceptors in the laryngopharyngeal (LP) mucosa receive innervation from the internal branch of the superior laryngeal nerve (SLN). Sensory information travels through the central nervous system via the NTS to the ipsilateral nucleus ambiguous (Xia, Leiter, & Bartlett, 2013). The cranial nerves, specifically the tri- geminal nerve (V) and facial nerve (VII) innervate the oral cavity and rostral pharynx, which function to give information about a bolus (a rounded mass) characteristic to the shape swallow motor response. Glossopharyngeal nerve (IX) and vagus nerve (X) are responsible for initiation of cough and swallow. The lingual branch of nerve IX innervates posterior tongue, tongue, vallate papillae and epiglottis. The pharyngeal branch of nerve IX directly involved in initiation of cough and swallow. Cranial nerve X divides into the SLN and recurrent laryngeal nerve (RLN). The internal branch of the SLN is critical for initiating reflexive cough and swallow (Tsujimura, Udemgba, Inoue, & Canning, 2013). Treating Speech Language Pathologies Assignment Laryngeal Reflexes (Table 13–1) Laryngeal Adductor Reflex What Is It? The laryngeal adductor reflex (LAR), also called the glottic closure reflex, is an involuntary protective response to stimuli in the larynx that can be initiated or triggered by laryngeal afferents. It is a mechanism of laryngeal protection, preventing material from inappropriately entering the upper airway. Figure 13–2 is an example electromyography (recording from muscle activity) for breathing, LAR, and swallow. Note the phasic TA activity during breathing, the increased activity during the LAR (in response to water), and the even greater activity during swallow. How Is It Tested? Pulses of air to the supraglottic space, innervated by the superior laryngeal nerve, elicit the LAR. In healthy individuals and patients with dysphagia, 50 msec laryngopharyngeal air pulses can stimulate LAR. These air pulse stimulations can be categorized by normal sensation (<5.4 cm H2O air pulse pressure to elicit the LAR), moderately impaired (5.4–8.2 cm H2O air pulse pressure to elicit the LAR), or severely impaired (>8.2 cm H2O air pulse pressure to elicit the LAR) (Aviv et al., 2002). Laryngospasm What Is It? A laryngospasm is a spasmodic closure of the glottis, or sudden forceful and abnormal closure of the vocal folds. Paradoxical vocal- cord dysfunction (PVCD) is characterized by CHAPTER 13 Laryngeal Reflexes 429 the inappropriate closure of vocal folds during inhalation, resulting in respiratory obstruction (Andrianopoulos, Gallivan, G. J., & Gallivan, K. H., 2000). During normal inspiration, the vocal cords are abducted, or open, and during expiration they adduct, or close slightly toward the midline. Under physical and emotional stress, laryngospasm can cause the vocal fold to adduct resulting in narrowing or even closure 430 Voice Disorders Figure 13–2. During breathing, water is infused into the airway stimulating the thyroarytenoid muscle and depressing the posterior cricoarytenoid, resulting in laryngeal adductor reflex. A swallow follows this reflex, stimulating the thyroid and thyroarytenoid muscles, and relaxing the upper esophageal sphincter (cricopharyngeus). of the glottis. An athlete with PVCD states that the neck and throat are the source of air- way restriction presenting with stridor. Stridor is a noise that is much harsher than wheezing, it resembles a high-pitched sawing noise (New- sham, Klaben, Miller, & Saunders, 2002). How Is It Tested? During exercise, full abduction of the vocal folds, dilation of the supraglottic and flattening of the epiglottis allow for increased airflow velocity and a decrease in resistance. Patients with PVCD have increased velocity and resistance at the laryngeal airway during inspiration due to inappropriate adduction of vocal folds (Gallena, Solomon, Johnson, Vossoughi, & Tian, 2015). The exaggeration of this reflex may result in complete glottis closure and blocked or delayed respiration, leading to hypoxia (low oxygen) and hypercapnia (high carbon dioxide). In the majority of patients, the prolonged hypoxia and hypercapnia eliminates the spastic reflex and the problem is self- limited (Alalami, Ayoub, & Baraka, 2008). Relaxed throat therapy is performed by inhaling through the nose and exhaling gently through pursed lips. Practitioners recommend that patient’s practice laryngeal control exercises daily and when they feel an upcoming episode (Newsham et al., 2002). Cough What Is It? Cough functions to clear materials that could be aspirated into the airways or already present in the airways. A cough starts with an inspiratory phase where the volume of air, generally larger than resting tidal volume, is rapidly inspired due to contraction of the diaphragm and external intercostal muscles. A brief compressive phase where the TA is activated to adduct the vocal folds and the expiratory muscles (abdominal and internal intercostal) contract against a closed glottis. The expiratory phase is marked by activation of the PCA with rapid abduction of the vocal folds and expiratory muscles are active (Nishino, 2000). How Is It Tested? Capsaicin cough challenge induces cough by the stimulation of TRPV1 receptor. Capsaicin can be delivered by the single dose method or the dose response method. The single dose method administers single concentrations of the tussive agent. The dose response method administers either single, vital capacity breaths of capsaicin via a nebulizer, or tidal breaths of incremental doses of capsaicin over a fixed period of time. The single dose method is favored due to its accuracy and reproducibility. It is advised to count the number of coughs within the initial 15 s after inhalation (Dicpinigaitis, 2007). A citric acid cough challenge administers citric acid in the same ways as capsaicin, but unlike capsaicin, it stimulates acid sensing ion channels (ASIC). This challenge has been associated with a choking sensation and pharyngeal discomfort more often than capsaicin challenge (Dicpinigaitis, 2007). Ultrasonically nebulized distilled water (UNDW) challenge is simply a fog that provokes severe coughing in healthy patients and patients with airway hyperactivity. This ultra- sonic nebulizer is considered a more useful research tool due to its ability to produce much larger output per unit volume than a standard conventional nebulizer (Dicpinigaitis, 2007). Arnold’s nerve ear-cough reflex: mechanical stimulation of the external auditory meatus activates the auricular branch of the vagus nerve (Arnold’s nerve) and evoke reflexive cough (Ryan, Gibson, & Birring, 2014). Cough can also be simulated with nasal irritation. It is well known that afferent nerves in the nasal mucosa are not able to initiate the cough reflex; but since afferent fibers from the nose project onto the NTS, it is speculated that they may converge onto and contribute to cough hypersensitivity. This was tested by having healthy participants inhale an aerosol of capsaicin solution. Application of the capsaicin into the nasal mucosa is immediately followed with a painful burning sensation. The cough response from the nasal capsaicin during nasal afferent stimulation increased compared to the control group, which used the intranasal saline (Plevkova, Brozmanova, & Tatar, 2004). Voluntary cough has been used to assess cough function when the above techniques are not possible, in a wide range of disease populations, including Parkinson’s disease and stroke (Smith Hammond et al., 2009; Pitts, Troche et al., 2010). Often the length of the compression phase is indicative of other respiratory reflex dysfunction, such as dysphagia. Cough During a Swallow Evaluation Common instruments used to evaluate swallow do have intrinsic measures for laryngeal sensations/reflexes. Penetration/aspiration scale (PA scale) is a measure developed and used by speech-language pathologists to evaluate pharyngeal dysphagia on video fluorographic examination of swallow. The highest degree on the PA scale is an 8. This is characterized by the bolus passes the glottis, visible subglottic CHAPTER 13 Laryngeal Reflexes 431 432 Voice Disorders residue, and no patient response, indicating this patient has aspirated, that is cough or throat clear (Rosenbek, Robbins, Roecker, Coyle, & Wood, 1996). Laryngeal Chemoreflex (LCR) What Is It? The laryngeal chemoreflex (LCR) is an airway protective reflex that includes startle, rapid swallowing, apnea, laryngeal constriction, hypertension (increased blood pressure), and bradycardia (fast heart rate) (Thach, 2001). It is initiated when gastric contents, water and other low pH, acidic solutions or low chloride concentration activate chemoreceptors in the perilaryngeal mucosa. The physiological manifestations of the LCR change over the course of postnatal life. In human infants, the reflex is characterized by inhibitory response, such as apnea and bradycardia, which gradually wane and are replaced by coughing and swallowing as the infant matures. The apneas that predominate early in life can be long lasting and result in repeated episodes of profound hypoxia and hypercapnia. (Donnelly, Bartlett, & Leiter, 2016). To result in apnea, an inhibitory reflex must overcome the individuals underlying drive to breathe. When that drive is reduced laryngeal reflex, apnea may be pro- found, long lasting and occasionally fatal (Xia et al., 2013). How Is It Tested? The more natural way to test LCR is by initiating liquids into the pharynx to the point where levels in the pyriform sinus gradually increase until they contact the LCR at the entrance of the laryngeal airway. Another method consists of perfusion of the larynx from below the vocal fold in tracheotomized animals. Even though the first method presented shorter duration of apnea than the second, it is a more natural way to stimulate LCR. Studies of sleeping human infants stimulated with water infused into the pharynx resulted in repeated swallowing, apnea, airway closure resulting in obstruction and infrequent coughing (Thach, 2001). Treating Speech Language Pathologies Assignment Aerodigestive tract is the mixed airway/ gastrointestinal tract including oral cavity, pharynx, paranasal sinuses, Sino-nasal tract, larynx, pyriform sinus, and upper esophagus. Treating Speech Language Pathologies Assignment Upregulation of Sensory Afferents Reflux Gastroesophageal reflux disease (GERD) is caused by the backflow of gastric contents into the upper digestive tract. It is associated with enhanced laryngeal reflex activity resulting in heightened cough reflex sensitivity when treated with inhaled capsaicin aerosol. It has also been shown that laryngeal C-fiber hypersensitivity is responsible for enhanced laryngeal reflex reactivity to ammonia induced by laryngeal treatment with pepsin. Pharmacological drugs that may suppress laryngeal C-fiber hypersensitivity are potential therapies for the treatment of patients with GERD (Liu et al., 2015). Laryngopharyngeal reflux (LPR) is the result of retrograde flow of gastric contents to the laryngopharynx, where it comes in contact with tissues of the upper aerodigestive tract. It is often referred to as “silent reflux” due to the difficulty of its nature in diagnosis. LPR differs from GERD in that it is often not associated with heartburn and regurgitation symptoms. The larynx is vulnerable to gastric reflux, so it is common for patients to present with. Treating Speech Language Pathologies Assignment ORDER NOW FOR CUSTOMIZED AND ORIGINAL ESSAY PAPERS laryngopharyngeal symptoms in the absence of heartburn and regurgitation (Ford, 2005). Viral Infections According to the Centers for Disease Control (CDC), in 2012, cough was the number one reason people go to the doctor. Upper and/or lower respiratory irritation caused by, sinusitis, common cold, flu all present with symptoms of runny nose, cough, sore throat, difficulty breathing and in some cases body aches and fatigue. In our everyday home remedies, it’s common to go to the drug store and load up on cough drops, vapor rub, decongestant, nasal sprays and cough syrup. What is it about these over-the-counter (OTC) drugs that make our infections better? Menthol is commonly used in cough drops, vapor rubs, and nasal sprays and works to block the cough reflex. As stated in a previous section, menthol activates TRPM8 receptors, which are located on C-fibers and Aä fibers, and gives a cool and soothing sensation leading to the suppression of irritation and cough. Brompheniramine malate is a first-generation antihistamine that is only the second reported drug that is able to reduce total symptom scores of rhinovirus colds. Total symptom scores include weight of nasal secretion, severity of rhinorrhea, sneeze, and cough; sneeze and cough count. It is unclear as to why brompheniramine suppresses cough but it is suggested that it has anticholinergic effects, which suppress cough and sneeze reflexes (Gwaltney & Druce, 1997). Irritable Larynx Syndrome (ILS) Diagnosis of ILS results from evidence of laryngeal tension, and/or presence of sensory triggers. It is hypothesized that ILS occurs when neural networks in the brainstem controlling the larynx are kept in a hyperexcitable state and react inappropriately to sensory stimulation. (Andrianopoulos et al., 2000). These patients often complain of chronic cough, laryngospasm, and high sensitivity to odors and gastric contents (Gillespie & Gart- ner-Schmidt, 2006). Odor-Induced Laryngeal Hypersensitivity Multiple chemical sensitivity (MCS), also known as idiopathic environmental intolerance (IEI), occurs when an individual has consistent and severe reactions to chemicals and odors that are commonly tolerated by the general population. Desensitization treatment uses multiple exposures at increasing levels to decrease the patient’s hypersensitivity responses (Gillespie & Gartner-Schmidt, 2006). Menthol serves as an additive in certain cigarette brands for flavor and to reduce/ hide the throat and sinus irritation caused by smoking (Millqvist, Ternesten-Hasse?us, & Bende, 2013). Chronic Cough A cough that persists for more than eight weeks is termed “chronic.” Cough hypersensitivity syndrome (CHS), coughing, is triggered by low levels of thermal, mechanical, or chemical exposure (Chung, 2011). Idiopathic cough is the chronic cough associated with conditions that are treated and do not lead to resolution of cough, and chronic cough is not associated with any conditions and unresponsive to any treatments (Chung, 2014). The initiating cause of the cough may disappear, but its effect on enhancing the cough reflex may have longer effects. For example, appearance of an upper CHAPTER 13 Laryngeal Reflexes 433 434 Voice Disorders respiratory tract infection or an exposure to toxic fumes that cause prolonged damage to airway mucosa may induce inflammatory neuropathic changes in the sensory nerves. The repetitive mechanical and physical effects of coughing bouts on airway cells could cause the release of various chemical media- tors that enhance chronic cough through inflammatory mechanisms, providing a positive feedforward system for cough persistence (Chung, 2014). Changes in airway nociceptors and mechanoreceptors can reduce the cough reflex threshold through the convergence of common second order neurons in the brainstem (Mazzone & Canning, 2002). This process may lead to the amplification of incoming signals received by the brainstem cough network. Amitriptyline and gabapentin are drugs used to treat chronic pain, but have been shown to reduce cough in chronic cough patients (Chung, 2014). Cigarette Smoking Cigarette smoking is one of the most common inhaled irritants of the respiratory tract. Smoking causes laryngeal sensory irritation due to the stimulation of laryngeal C-fibers by the activation and increased sensitivity of TRPV1, located on the laryngeal afferents (Liu et al., 2015). Studies show that long-term cigarette smoking significantly diminishes cough reflex. It is suggested this is due to desensitization of cough receptors within the airway epithelium. Long-term cigarette smoke also changes the character of airway mucus and could play a role in cough reflex sensitivity (Dicpinigaitis, 2003). Studies show that age-related vocal fold changes are one of the most common voice-related diagnoses in otolaryngology practices (Thomas, Harrison, & Stemple, 2008). Down Regulation of Sensory Afferents Aging Presbylarynx is the aging of voice, and atrophy of the thyroarytenoid (TA) is a primary fac- tor. Behavioral therapies such as strengthening the voice and surgical intervention involving augmentation or medialization of atrophic vocal folds have been found to reduce the glottal gap and improve voice and swallow functions. In aged rats there is a reduction in force, speed, and endurance of the TA muscle. With an increase in age, there are reductions in size and myelinated fibers of the SLN, and a decrease in density of sensory nerve endings in the larynx. This could be the reason as to why there is a reduction of laryngeal sensitivity with increased age. There is also presence of 4977-base pair deletion in the TA of aged human larynges with increased mitochondrial mutation. This indicates that mitochondrial changes play a role in laryngeal aging. There is a 42 to 60% reduction in laryngeal blood flow in aged rats, proposing that age-related vascular changes may alter the supply of oxy- gen (Thomas et al., 2008). Treating Speech Language Pathologies Assignment Neurodegenerative Diseases Parkinson’s Disease Parkinson’s disease (PD) is a chronic and progressive movement disorder. It involves the malfunction and death of neurons in the substantia nigra, which is one of the movement control centers in the brain located under the spinal cord. The substantia nigra produces the neurotransmitter dopamine, which controls movement and balance in the CNS. Symptoms of PD include tremors of the hands, legs, (etc.), bradykinesia (slow movement), rigidity stiffness of the limbs and trunk—and postural instability, which describes the impaired balance and coordination. CHAPTER 13 Laryngeal Reflexes 435 mediated pharyngeal response and laryngeal protection (Power et al., 2007). Dysphagia Altered LP sensation is a risk for the patient with impairment and possibly unsafe swallowing. It is found that isolated pharyngeal motor dysfunction with intact LP sensation predicted penetration and aspiration with pureed consistencies, whereas an isolated LP sensory deficit, with an intact pharyngeal squeeze maneuver (PSM), predicted penetration and aspiration with thin liquids. Most all patients with an absent LAR and PSM aspire both thin liquids and purees (Domer, Kuhn, & Belafsky, 2013). Treating Speech Language Pathologies Assignment Sudden Infant Death Syndrome Sudden infant death syndrome (SIDS) appears to occur when a presumed healthy sleeping infant experiences a challenge to cardiorespiratory homeostasis and fails to effectively respond (Donnelly et al., 2016). Studies show that prolonged apnea associated with LCR may be a cause of SIDS (Thach, 2001). References Alalami, A. A., Ayoub, C. M., & Baraka, A. S. (2008). Laryngospasm: Review of different pre- vention and treatment modalities. Paediatric Anaesthesia, 18(4), 281?288. Andrianopoulos, M. V., Gallivan, G. J., & Gal- livan, K. H. (2000). PVCM, PVCD, EPL, and irritable larynx syndrome: What are we talking about and how do we treat it? Journal of Voice, 14(4), 607?618. Aviv, J. E., Spitzer, J., Cohen, M., Ma, G., Belafsky, P., & Close, L. G. (2002). Laryngeal adductor reflex and pharyngeal squeeze as predictors of laryngeal penetration and aspiration. Laryngo- scope, 112(2), 338?341. Aspiration pneumonia is one of the lead- ing causes of death in patients with PD (Widdicombe & Singh, 2006). Those with PD may have a decreased ability to inflate the lungs, leading to the decrease in potential to generate high expiratory airflow for cough. High expiratory airflow velocity is created by narrowing the airways and adducting the vocal folds. High airflow velocity provides the force to aerosolize material and safely remove penetrants from the lungs during cough (Pitts et al., 2009). Reduced peak flows during voluntary cough are indications of increased risk of respiratory complications. Weaker expiratory peak airflow reduces the production of shearing forces, and decreases the ability to adequately clear mate- rial from the airway (Pitts et al., 2008). This can lead to aspiration pneumonia, which is swelling or infection of the lungs due to food, saliva, liquids, or vomit that is breathed into the lungs instead of being swallowed. Stroke A stroke occurs when blood flow to an area of the brain is cut off, resulting in lack of oxy- gen and brain cell death. Both voluntary and reflex cough, as well as expiration reflex, can be weak or absent, resulting in stroke patients at a higher risk for aspiration (Widdicombe & Singh, 2006). Hemispheric stroke patients have delayed pharyngeal response and delayed or absent swallow reflex, with impairments to pharyngeal sensation. It is hypothesized this is du