Developmental
Neurological
Structural
Medical
Behavioral
Bronchopulmonary dysplasia
Developmental delay
Intellectual disability
Down syndrome
Cerebral palsy
Pediatric CVA
TBI
Brain tumors
Neurosurgery
Cleft lip/palate
Genetic syndromes
Pierre Robin
Velocardiofacial syndromes
Williams syndrome
Noonan syndrome
Crouzon’s syndrome
GER(D)
Allergies
EE
Iatrogenic interventions
Intubation
Tracheostomy
Conditioned dysphagia post a medical condition
Picky eaters
ASD
Knowing the etiology underlying these difficulties is crucial for the accurate diagnosis of the swallowing disorder and treatment selection. The reason is that not all treatment options are appropriate for all pediatric patients. Oropharyngeal strengthening exercises may be ideal for children with reduced strength due to neurological or anatomical malformations but are traditionally contraindicated for children with increased spasticity in the head and neck. The pediatric swallowing specialist within a multidisciplinary team must be aware of the etiology causing the feeding and swallowing difficulties in order to provide appropriate treatment recommendations or referrals.
One of the main causes of developmental dysphagia can be prematurity. According to a recent systematic review on the causes of dysphagia across age groups, prematurity was the most commonly reported cause of dysphagia in newborns [14]. Prematurity (i.e., birth <37 weeks gestational age) means that the infant has to be able to breathe and feed before the aerodigestive systems are completely developed. In addition to this, in most situations the preterm infant also faces other medical conditions that may have to be treated invasively, exposing them to unpleasant experiences that further impact on feeding and swallowing development [15]. Frequently these factors lead to immature oral sensorimotor skills and inefficient sucking that can take considerable time and effort to remediate [16, 17]. Additionally, the preterm infant may present with respiratory compromise (bronchopulmonary dysplasia) contributing to difficulty coordinating the typical suck-swallow-breath cycle, a necessary skill for safe ingestion and airway protection [18].
Developmental dysphagia is also frequent in children with developmental delays and disorders that interfere with the developmental progression of swallowing and feeding skills (such as intellectual impairment, Down syndrome, or cerebral palsy) especially in the early years of life [5, 6, 11, 12, 19]. Developmental dysphagia in these populations typically is associated with impairments or delays in the development of mature eating skills as well as the complex of oropharyngeal sensorimotor swallowing functions [20].
Neurological etiologies affect the transmission of commands to and from the central nervous system resulting in impaired function of an otherwise normal structural oropharyngeal mechanism. In pediatric patients, typical neurological conditions that may affect or disrupt feeding and swallowing development include pre-, peri- and postnatal stroke leading to different forms and severity of cerebral palsy [5], traumatic brain injury [21], tumors affecting the brainstem and posterior fossa area [22], infant seizure disorders, and post-neurosurgical procedures [23]. Neurogenic dysphagia can manifest as difficulty in any of the swallowing phases but also is frequently accompanied by cognitive, alertness, language, and awareness deficits that can complicate symptoms and outcomes [24, 25].
Alternately, mechanical or structural abnormalities disrupt the anatomic or mechanical/physiological integrity of the oropharyngeal system leading to mechanical/structural dysphagia. Structural dysphagia in children can be congenital or acquired. Several structural abnormalities or conditions have been associated with feeding and swallowing difficulties in children. Some of the most common include cleft of the lip and/or palate and a variety of congenital genetic syndromes (such as Pierre Robin sequence, velocardiofacial syndromes, Williams syndrome, Noonan syndrome, Opitz BBB/G syndrome, etc.) that are frequently accompanied by developmental anomalies in one or more of the critical oropharyngeal and aerodigestive tract structures (nasal cavity, lips, mandible, tongue, palate, larynx, trachea, or esophagus) [26–29] [see authors’ note 1 in Case Study Box]. Inadequate development of these structures may lead to swallowing difficulties ranging from inadequate ability to form a labial or palatal seal and reduced ability to suck or form and transfer a bolus to decreased airway protection [30].
Case Study Box
History
AB was a 5-year, 6-month-old male with a diagnosis of Opitz BBB/G syndrome and Asperger’s syndrome. Anatomical anomalies in association with the Opitz BBB/G syndrome included level III laryngo-esophageal cleft, laryngomalacia, subglottic stenosis, and unilateral cleft of the upper lip and alveolar ridge, all of which were surgically corrected in the first 5 years of life. AB was also status post tracheostomy with tracheostomy decannulation occurring 10 months prior to the initiation of the program. AB had been totally dependent on gastrostomy tube (GT) feeding for nutrition and hydration since 3 weeks old. He had transitioned from GT feeding to a liquid diet taken only by straw in the last 2 weeks before our team saw him at age 5 or 6.
Authors ’ note 1: This is a typical example of a pediatric patient who experienced severe dysphagia due to a genetic syndrome causing multiple anatomic malformations. In addition, he has the behavioral characteristics of autism spectrum disorder. Post medical and surgical interventions, the child experienced conditioned dysphagia and avoidance behaviors that are often associated with prolonged interruption of oral feeding. Further, he had not had the opportunity to develop eating skills.
Feeding/Swallowing Evaluation
At the time of the evaluation, he fed himself a liquid-only diet at a rate of 32 mL/min; he was not accepting or swallowing puree or other solid foods and he was not eating from spoon or fork or drinking from an open cup. Thus, his oral feeding development was significantly delayed for his age. In addition, there were concerns with persistent aerophagia (i.e., excessive air swallowing), which became more apparent post decannulation and required frequent air suctioning from the GT to alleviate stomach distention and feelings of pain and discomfort. Although he had recurrent bouts of pneumonia in the past, he had been free from a pneumonia diagnosis for the past 3 months. Body Mass Index indicated that his nutrition was within normal limits for his age. A videofluoroscopic swallowing study (VFSS) was performed, which revealed no aspiration or penetration and no apparent oropharyngeal swallowing difficulties on the small boluses of liquids that he was able to swallow during the examination. Medications at baseline included azithromycin, Movicol, and Dulcolax. AB also had multiple food and environmental allergies. He had no apparent gross or fine motor deficiencies or difficulties, and speech and language appeared to be developing normally.
He was referred to our team for assistance with developing eating skills and tolerances for solid foods.
Authors ’ note 2: A clinical and instrumental evaluation was completed with this patient, as he exhibited significant oral feeding development delays and physiological symptoms (aerophagia), which needed to be examined clinically and instrumentally. The videofluoroscopic study revealed normal oropharyngeal swallowing, and thus the feeding program focused on the behavioral aspects of his dysphagia.
Treatment Program
Treatment focused on the following parameters that were found to be disordered during the evaluation: (1) oral acceptance/tolerance of eating-related objects and a variety of foods/flavors via spoon, (2) control of voluntary saliva swallows to improve aerophagia levels, (3) increase bolus size, and (4) increasing independence during feeding. The following techniques were used to address these parameters: (a) blocked sequence practice (e.g., AB was asked to practice one task at a time for multiple repetitions, then rest and practice again), (b) reduced response effort (e.g., AB practiced inserting a simulated spoon in his mouth prior to initiating spoon-feeding), (c) extrinsic feedback (e.g., frequent and immediate verbal acknowledgment of adequate performance was provided to AB for most tasks), (d) reinforcement (e.g., a sticker was given to AB after each successfully completed activity), and (e) new strategy “racing car swallow” to improve aerophagia and control of voluntary swallows (this was a strategy developed based on patient’s interests in racing cars). We also used straw drinking (technique f), because this was a well-developed skill for AB to continue improving orobuccal coordination. Lastly, we encouraged AB to use a chin tuck posture (technique g) as an added safety precaution and a means for better assurance that he was using a propulsion swallow.
Authors ’ note 3: The techniques described above include examples of motor learning techniques (techniques a–e), one strengthening technique (technique f), and one compensatory strategy (technique g).
Oropharyngeal dysphagia in children can also result from a variety of medical conditions and/or procedures. Two of the most common medical conditions known to result in feeding and swallowing challenges include gastroesophageal reflux (GER) and allergies [31]. GER can be present in up to 85 % of infants and has been found to be more severe in high-risk neonates [32]. In most infants GER is considered a normal physiologic process that occurs several times per day and does not cause overt symptoms of discomfort [33]. In rare cases (about 5 %), it can persist beyond the first year of life. When GER progresses to GER disease (GERD), symptoms may range from feeding and sleeping difficulties, esophagitis, and pulmonary problems to failure to thrive and risk for aspiration [34]. Additionally, there is a high prevalence of GERD in children with intellectual and developmental disability that may present with rumination, vomiting, and behavioral issues [35]. GER can frequently coexist with food allergies including the frequent cow’s milk protein allergy (CMPA). Food allergies and GER can cause discomfort and even pain during eating, experiences that can make eating undesirable for an infant or young child. Such conditions may further lead to conditioned dysphagia and avoidance behaviors during feeding in order for the child to avoid the discomfort and the pain [31]. Another related condition that appears to be frequently associated with dysphagia and feeding difficulties in children is eosinophilic esophagitis (EE). EE is a condition in which there is a dense infiltrate of eosinophils (white blood cells) on the esophageal mucosa, without the presence of GER [36]. The exact cause of EE is not well known; however, allergic causes [37] and some genetic predisposition have been reported [38]. Typical symptoms of EE include vomiting, dysphagia, feeding disorders, heartburn, and food impaction [37]. Additionally, children who have suffered from variable medical conditions, such as cardiac, orofacial, laryngeal, and pulmonary surgeries, or have experienced invasive medical procedures, such as intubation and tracheostomy, may develop analogous avoidance behaviors or even lack of appetite and motivation to eat, especially if eating has been interrupted for a long period of time or takes extra time and effort [29, 39–41]. Thus, medical dysphagia can easily result or manifest as behavioral dysphagia, which was conditioned aversions based on unpleasant experiences [see authors’ note 1 in Case Study Box]. Typically, in these cases, there is delayed development of skills as well.
Behavioral dysphagia can result from some of the conditions described above or can be the result of neurodevelopmental disorders such as autism spectrum disorders (ASD) [42, 43]. Children with ASDs do not usually present with the typical inadequacies in oropharyngeal competencies described above but more commonly present with increased food selectivity regarding the type, brand, texture, temperature, or color of food (often called “picky eaters”) [43, 44], a restricted dietary inventory [42], and in some cases atypical eating habits, such as tendency to eat inedible objects referred to as foreign body ingestion and pica [45, 46]. Additionally, adipsia and inability or refusal to ingest enough fluids have also been reported in cases with ASD and could potentially lead to further nutritional and gastrointestinal deficiencies [47]. These behaviors are often the result of a combination of sensory awareness and processing challenges potentially including all sensory modalities (gustatory, tactile, visual, auditory, proprioceptive, etc.), gastroesophageal difficulties (with GER being the most commonly reported), the urge for stereotypic behaviors, and executive function limitations, such as difficulties in planning or self-monitoring during the eating process [48].
For the medical professional who treats any of the aforementioned dysphagias, it is crucial to understand the normal development of feeding and eating behaviors and processes before they can offer a comprehensive diagnostic and therapeutic plan. Next we offer a concise review of the normal development of feeding and swallowing from the prenatal period to early childhood.
Normal Feeding and Swallowing Development
Understanding normal development is crucial in providing correct diagnosis and treatment in pediatric dysphagia. The rapid growth of technology has allowed for exciting opportunities for new knowledge on the development of swallowing and feeding in the pre- and postnatal periods.
Prenatal Period
Prenatally, the aerodigestive tract organs important for swallowing are developed during the embryonic period (weeks 1–8 of gestation) [49]. On the 3rd week of gestation, the three embryonic germ layers form (ectoderm, endoderm, mesoderm), which will later give rise to all the tissues and organs associated with swallowing. The digestive system develops between the 4th and 8th week of gestation, with the oropharynx including the tongue developing at the 5th week, followed by the labial muscles and the upper lip fusion by the 7th week of gestation [50]. Palatal development begins at the same time and is complete by the 12th week [51]. A combined laryngotracheal-esophageal tube starts separating by the 4th week of gestation providing a complete separation between the airway and the esophagus except for the level of the larynx. Thus, the esophagus starts developing at the 4th week; by week ten, it is lined by ciliated epithelial cells, and at 4 months, these cells start being replaced by squamous epithelial cells [52]. Respiratory and neural development initiates early but continues post the embryonic period and until birth [30]. The presence of immature taste buds on the tongue has been observed as early as the 7th week of gestation [53].
During the fetal period (9–28 weeks of gestation), there is continued rapid growth of structures and the first functions related to sucking and swallowing. Early oral movements, such as tongue thrusting and lip and jaw motions, have been noted as early as 15 weeks of gestation and are believed to be precursors for sucking and swallowing functions [54, 55]. These movements are seen to progress from simple open-close or anterior movements to the more complex repetitive movements typically seen in postnatal sucking. Swallowing has been observed as early as the 12th week of gestation, as the fetus swallows amniotic fluid. According to Miller and colleagues [56], bolus swallows more typically occur from 15 to 38 weeks gestational age (GA), with the most active period of swallowing occurring between 17 and 30 weeks GA [56]. Swallowing of amniotic fluid by the fetus is important in the regulation of the composition of the fluid and for the development of the gastrointestinal tract [57]. During these immature swallows, several functions, such as labial and velopharyngeal closure or even laryngeal elevation and airway closure, are not consistently observed [56, 58]. Swallowing in the fetus is also primarily seen in the presence of precedent oral-facial stimulatory activity, such as facial, ear, and labial swiping using the arm or hand, which starts as early as the 10th week of gestation [59]. Additionally, the taste buds typically develop into more morphologically mature taste buds by the 12th week [60]. There is preliminary evidence that the human taste system is functional in utero [61], although more research is needed in this area. According to Arvedson [62], a healthy preterm infant can suck and swallow functionally enough to maintain their nutritional needs with oral feeding by 34 weeks of gestation.
Postnatal Period: Infancy to 6 Months
Before we elaborate on the typical feeding and swallowing development in this period, we need to define two terms. The term “swallowing” refers to the complex sensorimotor sequence of events that are initiated by recognizing the presence (touch), taste, temperature, and viscosity of food or fluid in the oral cavity, followed by the preparation, in the case of food, to a consistency that can be swallowed, and finalized by its safe transportation through the oral, pharyngeal, and esophageal anatomic structures to the stomach [63]. “Feeding” refers to anticipatory events, such as motivation and readiness for eating, food acceptance, and also the important interactions developed between the infant and the caregiver/feeder during the feeding process [64]. How do these functions develop in the first months of life?
Normal feeding and swallowing milestones in infancy are achieved in parallel with other important psychosocial, sensorimotor, and cognitive development milestones. The full-term infant feels hunger and via infant oral reflexes (rooting reflex) searches for a breast or bottle nipple to initiate sucking and swallowing [62]. Healthy term and preterm infants can coordinate the sucking, swallowing, and breathing triad within 1–2 weeks post birth. According to Kelly and colleagues [65], any changes or irregularities seen in this coordination in the 1st weeks of life depend on neural or anatomical development or overall feeding experience.
The tongue and jaw plays a very important role in the execution of nutritive sucking (NS) (sucking conducted for nutritional purposes). Specifically, for the initiation of nutritive sucking, the tongue is known to either secure the nipple at the hard-soft palate junction and then initiate a downward movement for milk suction and upward movement for expression [66] or to be “anchored” at the anterior sulcus and initiate suction and expression movements [59]. Sucking may also be nonnutritive (NNS) occurring in infancy as an action on a hand or an object, usually a blocked nipple. In the premature infant, it occurs prior to readiness for NS. NNS in the infant is important for self-regulation, respiratory balance, feeding stability, and gastrointestinal health [67, 68]. A common scale used to evaluate sucking maturity in preterm and term infants involves five differential levels (Table 9.2) and was developed by Lau et al. (2000).
Sucking development stages |
|---|
1a: No suction |
1b: Arrhythmic alteration between suction and expression |
2a: No suction; rhythmic expression |
2b: Arrhythmic alteration between suction and expression, but also presence of sucking bursts |
3a: No suction; rhythmic expression |
3b: Rhythmic suction and expression; increase in suction amplitude, amplitude range, and duration of sucking bursts |
4: Rhythmic suction and expression; suction is now well defined, decrease in amplitude range |
5: Rhythmic, well-defined suction and expression; increase in suction amplitude; full-term infant sucking pattern |
During the first months of feeding development, the infant has a flexed body posture, and his/her oral motor skills (such as lip closure, anterior-posterior movement of the tongue, and jaw range of motion) gradually improve. Simultaneously, several neuromotor and psychosocial milestones are achieved, including visual fixation, eye tracking [70, 71], more balanced body, neck and trunk support [72], ability to express hunger cues (through crying, arousal, sucking, etc.) [73], and increasing interaction between the feeder and the child that further facilitates a successful feeding experience. By 4 months, the infant can dissociate the lip and the tongue, and oral exploration is increased, as evidenced by increased labial movements, by performance of raspberries (bubbles formed with saliva and intense labial exploration by the infant), and by increased sound production [74]. By the 5th month, some infants are ready to initiate cup drinking [62]. Also, they now visually recognize objects and familiar faces and can use extended reach and grasp [71], and they are ready to initiate a more upright posture during feeding.
Six Months to 3 Years of Life
At around 6 months of life, transitional feeding is initiated, which includes the transition from bottle/nipple to spoon-feeding. The exact point in time when spoon-feeding is initiated depends on multiple environmental, neurodevelopmental, and feeding development factors. Specifically, Arvedson suggests that spoon-feeding readiness in the typically developing child depends on factors such as ability to maintain upright sitting posture and midline position of the head independently, hand to mouth movements, dissociation of labial and lingual movements, and anatomic head and neck changes that allow for more flexible lingual and jaw movements [62]. At about this time, the suck-swallow used for nipple feeding transitions from a swallow that depends on the gravity for transferring the bolus into the pharynx to one that depends on tongue propulsion. In the next few months (6–9 months), the child’s oral and pharyngeal motor skills continue to mature, and the skill of eating thicker and lumpier foods develops, followed by finger feeding of easily dissolvable and soft chewable foods at 9–12 months and overall increased independence. A delay in the introduction of lumpy foods has been associated with reduced variety of foods accepted at later months of life and with increased incidence of feeding difficulties [75] and thus should be avoided. Chewing is rather stereotypical initially characterized by immature vertical movements caused by reciprocally activated antagonistic muscle groups [76] and gradually matures and requires less time and fewer chewing cycles [77]. Cup drinking is initiated at around the same time and may be challenging at first, but in most healthy children, this skill matures by the 15th month of age [73]. In addition to physiological readiness, the timing for acquisition of these skills depends on the introduction of foods and supports needed for practice of the skills [78].
By 13–18 months of life, healthy children are able to accept most textures, can coordinate phonation, swallowing and breathing rather well, and can initiate safe straw drinking [73]. By the second year of life, the child can self-feed adequately, a rotary chewing pattern has developed [77], and food intake is now independent. By the third year of life, most feeding and swallowing skills have acquired near-adultlike form, for unrestricted variety of food and liquid. The child eats with good jaw rotations as needed and complete mastication of the bolus and exhibits steady cup holding and drinking, use of fork, and total self-feeding [62].
Significant Considerations
The knowledge of normal development of feeding and swallowing skills is important in order to accurately evaluate differences and deviations in pediatric patients. Several considerations should be noted, however. First, the aforementioned milestones represent the course of feeding development for typically developing children, but a range of variability in the exact timing of acquisition of specific skills is to be expected. Differences may be seen because of cultural, geographical, or idiosyncratic reasons, and clinicians/physicians need to be aware of those. Additionally, according to Delaney and Arvedson, for preterm infants, clinicians should use age adjustments for the first 2 years of life before making determinations for diagnostic and therapeutic goals [64]. Development of feeding skills in preterm infants should be evaluated in the context of their adjusted age and general psychomotor development.
Another important consideration involves the concept of critical and sensitive periods in feeding development [79, 80]. These periods in relation to feeding mainly refer to the periods during which a child needs to transition from a simpler food type/consistency to a more advanced food type/consistency (mostly from liquids to solids). Although the exact range of months for the acquisition of each developmental skill is not absolute and can vary in normal infants and children, research has shown that children who are delayed in the introduction of new food consistencies (e.g., lumpy foods) will consume a reduced variety of foods later in life [75, 81] and that food acceptance is higher in children between 1 and 2 years of age and decreases significantly in the years following the second year of life [82]. This evidence supports the concept of critical/sensitive periods for feeding development. In addition, all the oropharyngeal, general motor, and respiratory physiological processes that govern feeding development also undergo critical/sensitive periods and should be considered [62]. In normally developing children, the parents should be encouraged to follow the typical feeding milestones described herein. In children with neurodevelopmental delays or disorders, however, additional factors including psychosocial, neuromotor, cognitive, medical, and general development should also be considered, before the determination to advance to a different food/consistency type is made.
Assessment Approaches
Clinical Dysphagia Assessment
As in the adult, dysphagia diagnosis in pediatrics may require a combination of clinical and instrumental assessments to fully evaluate the swallow and determine the contributing causes. Comprehensive classification systems have provided discrete categories of structural abnormalities, neurologic conditions, behavioral issues, cardiorespiratory problems, and metabolic disorders [7]. However, the clinical dynamic in pediatric dysphagia is most often a combination of physiologic, behavioral, and developmental features that are challenging for both diagnosis and treatment [13, 83, 84].
Screening Models
Subjective models that screen for referral for the CDE may include items that describe signs and symptoms of disorder or failed readiness for transitions. They may include, for example, prolonged (slow) feeding, respiratory signs associated with eating or saliva swallowing, repeated lower respiratory infections, persistent food refusal or restricted food preferences, irritability during meals, restricted food intake at meals, emesis associated with meals, interrupted or slow weight gain, failure to transition as expected to more mature eating patterns or foods and eating independence, and episodes of dehydration or choking [1, 2, 5, 83, 85].
Standardized screening assessments, tests that estimate presence, and may describe the clinical presentation, of disorder but do not address contributing causes, have been tested for pediatric applications. The 3-ounce water challenge was studied for its use to screen for aspiration. Children 2–18 years old able to drink 3 ounces of water by cup or straw were tested. Indications for failure were inability to drink the 3 ounces and coughing. Results indicated that there were adequate sensitivity and specificity for its use as a screening; however, further clinical assessment was needed for determining indicators for appropriate feeding status and diet [86]. The dysphagia disorder scale, a screening assessment for presence of dysphagia in children and adults with developmental disability, is administered during an observation of a meal or snack. Study results have found it to be a reliable and valid test for identifying and describing the clinical presentation of swallowing and feeding disorders. When used in conjunction with an ordinal scale, the dysphagia management staging scale, it provides a measure of functional severity of disorder [2, 87]. Parent-report inventories have been standardized for use in pediatric dysphagia for children with autism [88], for children who are tube fed [89], and for a range of problematic eating behaviors that include dysphagia [90, 91].
The Clinical Dysphagia Evaluation
The clinical dysphagia evaluation (CDE) is considered to be pivotal as a minimally invasive method for determining signs and symptoms of dysphagia. It is during the CDE that the clinician makes the preliminary determination of the dysphagia diagnosis and the categories of contributing cause and decides whether or not the condition warrants instrumental or collaborative team assessments to further delineate the parameters of the swallowing and feeding disorder. The CDE determines the clinically apparent signs and symptoms [84, 92, 93].
Subjective models for pediatric CDE may include the case history, examination of oral, pharyngeal, facial and thoracic anatomy, examination of oral and pharyngeal reflexes, and the observation of swallowing function for saliva, foods, and liquids. The case history can be extensive, including family, medical, nutritional, developmental, and feeding information that suggest possible etiologies, causes, and consequences of the complaint. During observations of infant reflex responses and swallowing and feeding function, the integrity of cranial nerve participation is analyzed. Judgments are made as to the adequacy of body postural control and alignment and breath support and swallow-breathing coordination. In pediatrics, considerations are included for developmental levels for eating milestones and for levels of independence, motivation for eating, and eating pragmatics. These diagnostic CDE models have been developed for infants and for older children [1, 2, 93, 94].
Objective clinical assessments have been developed for standardized observation of sucking in infants and oropharyngeal dysphagia in children. These assessments can be valuable as they have been shown to reduce clinician bias and provide levels of assurance of validity, reliability, and responsiveness. However useful these assessments may be, psychometric limitations have been noted [87, 95–98]. Generally, these assessments have been standardized for specific populations and specific feeding skills. Howe and colleagues reviewed dysphagia assessments that have been developed for preterm and term infants, for breastfeeding and bottle-feeding, and for evaluating infant function and maternal participation [95]. Benfer and colleagues reviewed assessments of oropharyngeal dysphagia that have been developed for children with cerebral palsy and neurodevelopmental disabilities. These assessments examine swallowing and feeding function variably in natural eating situations and with test items that include a range of solid and fluid foods [96, 99].
Ordinal scales have been developed for classifying levels of severity of swallowing and feeding disorder in cerebral palsy. Few are standardized [100, 101]. The ordinal parameters vary from overall measures of function to measures of specific competencies, e.g., food textures, assistance needed for eating, respiratory illness, and risk for aspiration. Standardized assessments for objectifying observations of specific, clinically apparent skills and for examining the behavioral milieu during eating have been useful in clinical practice and research. Examples of this type of clinical assessment are an observation of mother-infant interaction and an observation of mastication [89, 91, 99, 102–104].
Instrumental Assessments
Oropharyngeal Dysphagia
While the CDE is effective for describing the oral preparatory phase of swallowing, including deficiencies in eating skills and for behaviors associated with eating [96], it has limitations for discriminating events in the oropharyngeal and esophageal phases of swallowing. DeMatteo and colleagues tested these limitations and found that experienced clinicians could detect aspiration of fluids with a sensitivity of 92 % in the CDE as compared to the videofluoroscopic swallowing study (VFSS). Sensitivity for aspiration of solid food, however, was less adequate at 33 %. Sensitivity for esophageal disorder was not tested.
Instrumental assessments are indicated when it is expected that the results will further describe the parameters of the disorder and will inform intervention decisions. Typically, clinicians have depended on instrumental measures to supplement the CDE when there are indications that oropharyngeal or esophageal dysphagia involvement is contributing to the disorder or when CDE findings do not adequately explain the symptomatology [105]. The choice of test depends on the presenting signs and symptoms. Videofluoroscopy and fiberoptic endoscopy are well-accepted options in pediatric practice for viewing upper airway and pharyngeal anatomy and bolus motility in the oral and pharyngeal phases of swallowing [92, 106, 107]. In addition, VFSS is indicated for direct viewing of the pharyngeal swallow and screening bolus motility and anatomy in the esophagus [106, 107].
Referral criteria for VFSS or FEES are signs of oropharyngeal dysphagia, a diagnosis that suggests a high prevalence of oropharyngeal dysphagia and risk for aspiration, and the probability that the child will tolerate the examination sufficiently to provide valid results [84, 92, 107–109].
The VFSS is a radiographic, qualitative, dynamic assessment that continues to be considered as the gold standard in pediatrics for assessing the biomechanics of swallowing and the adequacy of airway protection. The limitations include exposure to ionizing radiation, the need for a time-limited examination, the need for patient cooperation, and the challenging test environment [92, 93, 106, 110]. During VFSS the child is in a position that simulates natural feeding but is constrained by the need for lateral and anterior-posterior fluoroscopic views of the swallow. The unique advantage of VFSS is that the bolus can be followed from the mouth into the stomach, providing radiographic views of anatomy and physiology and of the timing, biomechanics, bolus flow, and effectiveness of the whole swallow for a barium-impregnated bolus of solid and liquid food. Visualization of penetration, aspiration, and esophageal function is possible [see authors’ note 2 in Case Study Box].
Fiberoptic endoscopic evaluations of swallow without sensory testing (FEES) and with sensory testing (FEEST) are receiving increasing attention as an alternative to VFSS for evaluating pediatric dysphagia [84, 111–114]. During FEES a soft, flexible nasopharyngoscope is inserted in the nose and positioned between the soft palate and the epiglottis (oropharynx). Oral and pharyngeal anatomy and selective swallowing events can be viewed for saliva and the child’s typical solid and liquid food in familiar postural alignments. A blackout of the view occurs during pharyngeal contraction obscuring the pharyngeal biomechanics during the pharyngeal swallowing response. Signs of aspiration and penetration are apparent prior or following the swallow. During FEEST puffs of air delivered to the aryepiglottic folds test the sensory threshold for the laryngeal adductor reflex. The resulting laryngopharyngeal sensory threshold (LPST) has been found to be related to the number of abnormal oropharyngeal swallowing function parameters and prevalence of aspiration tended to increase when LPST was severely impaired [112]; however, research on this method is sparse. FEES and FEEST are preferred for the child who has never fed orally or accepts insufficient food for VFSS. It allows observations for structure, non-swallowing functions of the upper airway, management of saliva accumulations, intactness of sensation, and spontaneous swallowing as it occurs for accumulations of saliva, all without the introduction of food [84].
There have been a number of studies comparing FEES and VFSS. A preliminary study that compared the swallowing in infants and children before and after placement of the endoscope in the upper airway found no change in swallowing outcomes, and simultaneous ratings were in agreement [84, 111, 115]. FEES had advantages for detecting anatomical anomalies in the upper airway [111, 116] and for testing pharyngolaryngeal sensation [112] and has similar results for detection of laryngeal penetration and laryngotracheal aspiration with VFSS [117, 118].
There are less invasive procedures that have also been used for the objective evaluation of pediatric oral preparatory and oropharyngeal swallowing; however, clinical applications have been limited. Electromyography (EMG) was found to provide useful information regarding level of effort in labial, mandibular, and cervical musculature during swallowing in older children with Duchenne muscular dystrophy (DMD). The EMG procedure differentiated the normal control subjects from the DMD subjects and was well tolerated [119]. Furthermore, it identified weakness in masseter muscles in children diagnosed with spastic cerebral palsy as compared to normal control subjects [120]. Ultrasound, another one of the objective, less invasive evaluation procedures, has been found to be uniquely suited for the assessment of infant sucking. It was useful for evaluating sucking in infants with ankyloglossia pre- and post-frenulotomy, for evaluating breastfeeding and for comparing lingual and hyoid movement patterns in a premature infant during nonnutritive and nutritive sucking [59, 121–123]. Although its use has been reported infrequently for older children, it has been found to be useful for differentiating the oral preparatory and oropharyngeal swallowing in disabled children from that of control subjects [123, 124].
Esophageal Dysphagia
The differential diagnosis of esophageal dysphagia in children can be challenging for the swallowing specialist and physician and confusing to parents as it often presents as feeding difficulty with similar behavioral and developmental deficiencies as those seen in oral preparation and oropharyngeal phase dysphagia.
Esophageal dysphagia may result from anatomical anomalies, GER, inflammation, or neurological disorder [125–128]. Congenital and acquired anatomical anomalies in the esophagus and motor dysfunction occur less frequently. Videofluoroscopic studies can screen for anatomic abnormalities, such as webs and strictures; for esophageal motor disorders such as achalasia of the upper and lower sphincters; and for mucosal anomalies [128]. An esophageal screening during a VFSS can provide preliminary information that indicates the need for additional assessments [106]. Esophageal pH and pH impedance monitoring may be useful for diagnosis of GERD in infants and children. Endoscopic and histologic evaluations may be used to differentiate eosinophilic esophagitis from GERD [129, 130]. High-resolution manometry is an available technology for differential diagnosis of esophageal motility disorders in children [131] and for pharyngo-esophageal motility disorders [132]. Combinations of manometry and videofluoroscopy and manometry and impedance techniques have been reported to provide objective measures of pharyngo-esophageal swallowing dynamics with diagnostic utility in pediatrics [133, 134].
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