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5 Voice, Speech, and Language

Nonorganic voice disorders, speech fluency, articulation, and language are a field for specialized physicians, known as phoniatricians. The training provided for these specialists is not standardized across Europe. Some start as otolaryngologists for 2 years and then focus on the diagnosis and treatment of communication disorders. Others are otolaryngologists who specialize later during their career. Phoniatrics is not a commonly known subspecialty, but phoniatric centers are scattered all over Europe. In the United States, otolaryngologists with a special interest in laryngology provide care for voice patients. Communication disorders that are not treated medically are subject to treatment by speech and language therapists or speech-language pathologists. In the Scandinavian countries and in central and eastern Europe, these therapists are also called logopedists.

5.1 Voice

5.1.1 Voice Production

Voice involves interaction between the respiratory system, larynx, vocal tract, articulatory organs, and cerebral coordination. Vocalization means producing sound, preferably on an emotional level; phonation is sound production with the aim of communicating by speech or singing. The two terms are interchangeable. The coordination of phonation originates in two centers in the brain—the limbic system and the primary motor area of articulatory organs in the cortex.

5.1.1.1 Glottal Sound Generation

Modulation of the air stream during phonation is controlled through the interaction of the vocal folds with the air stream, which results in passive vibration of the vocal folds. The configuration of the glottal aperture and its elasticity during phonation is adjusted by the neuromuscular system. The vocal folds adduct, contract, and tense. According to the myoelastic-aerodynamic theory in voice initiation, the vocal folds adduct, forming a slightly closed or narrow channel between the subglottic and supraglottic airways. During expiration, air pressure builds up at the level of the glottis and pushes against the vocal folds. Sufficient air pressure pushes air through the glottal aperture. The following forces close the glottis:

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  Bernoulli’s effect of airflow through the glottis generates a negative force that pulls the vocal folds medially.

  
  
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  The elasticity of the vocal folds (passive recoiling) returns the vocal fold tissue to the shape it had before it was deformed by transglottic pressure.

  
  
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  Air passing through the glottis from the subglottic reservoir causes a fall in subglottic pressure. The driving force pushing the vocal folds apart decreases.

When the vocal folds close and obstruct airflow, subglottic pressure builds up to deform the vocal fold tissue and start another cycle of the opening phase. This process as a whole is called the glottic cycle. Characteristic phases of glottal deformation during vibration are shown in ▶ Fig. 5.1.

The fundamental frequency determines the perceived pitch of the voice, which is related to the number of vibrations of the vocal folds per second (Hz). The recurrent laryngeal nerve sends neural signals to the laryngeal musculature, which varies the tension of the folds and their configuration. This leads to tones at different frequencies and loudness levels.

5.1.1.2 Body-Cover Model

The body-cover model is an attempt to classify the connective-tissue structures of the vocal fold into functional units ( ▶ Table 5.1 ). It groups the five anatomical tissue layers of the vocal fold (see also ▶ Fig. 4.2a, b) into three functional layers: The first layer, called the cover, consists of the epithelium and superficial lamina propria. The cover is pliable, elastic, and nonmuscular. The second layer, called the transition, is the vocal ligament, consisting of the elastic and collagen fibers of the intermediate and deep layers of the lamina propria. The third layer, called the body, consists of the medial thyroarytenoid or vocalis muscle. It is stiff. The effective tension of the vocal folds depends on the interaction between the cover and the body, which is adjusted by muscle contraction.

5.1.1.3 Source-Filter Theory

Vocalization is sound production in the larynx. It does not necessarily involve articulation. However, all human voice productions are altered when they pass the vocal tract. The configuration of the tract determines the sound that emerges from the lips. The acoustic properties of the vocal tract shape the spectrum of the primary glottal source, as explained by the source-filter theory. This is based on the notion that the spectrum of the laryngeal voice source and the vocal tract resonator are clearly separable and independent. Sound produced in the glottis travels through the air-filled supraglottic space, the throat, and the oral and nasal cavities before being emitted into the environment ( ▶ Fig. 5.2). The air in this vocal tract resonator has multiple resonance frequencies at which it enhances existing spectral components (harmonics). These vocal tract resonances (formants) act as filters that shape the spectrum of the sound generated by the source (larynx) to produce an output signal that is a combination of source and filter ( ▶ Fig. 5.3). The different sounds of human speech (phonemes) depend strongly on formants. In all human languages, vowels are distinguished by the frequencies of the two lowest formants ( ▶ Fig. 5.4). The third, fourth, and fifth formants are of greater significance to personal voice timbre.

5.1.2 Voice Diagnosis

The following aspects need to be taken into account when assessing common forms of dysphonia.

History: The patient’s history should reveal causes of the disturbed voice function—beginning with the age, the voice problem, whether it is acute or chronic, and whether it is related to vocal load or environmental irritants. What is the patient’s overall physical condition? Are there any allergies or breathing problems, or is the patient a smoker? Is food affecting the voice? Reflux may cause voice problems. Sex hormones can alter the voice. Hearing loss is a source of vocal problems. Surgery in the throat, larynx, or neck, or intubation, as well as medications and drugs, can alter the voice.

Is the voice abused during speaking or during singing? Does the patient have pain when talking or singing? Laryngologists should ask about the amount of vocal exercises and their duration, the time of day, and activities that have adverse effects on the vocal folds such as weightlifting, aerobics, and playing of some wind instruments. Information about voice training may reveal technical deficiencies. Pressing commitments to events requiring public speaking or singing may cause physical and emotional stress.

Voice registration: Audio recording is the most valuable basic tool for voice assessment, for blind perceptual evaluation by a panel, or for sophisticated acoustic analyses. It is essential for all recordings of voice patients to be filed as an archive from which it is easy to retrieve an earlier sample. A digital recording system should be used to store signals and a sampling frequency of at least 20,000 Hz is recommended. For the recordings, a quiet room with ambient noise <50 dB is acceptable. The mouth-to-microphone distance needs to be kept constant at 10 cm.

Perception: The rating is based on the patient’s speech while reading a text. Two main components of hoarseness have been identified:

Breathiness (B): an audible impression of turbulent air leakage through an insufficient glottic closure may include short aphonic moments (unvoiced segments).

Roughness (R) or harshness: an audible impression of irregular glottic pulses, abnormal fluctuations in fundamental frequency (F₀), and separately perceived acoustic impulses (as in vocal fry), including diplophonia and register breaks.

The severity of hoarseness is quantified using the parameter G (grade). This represents the overall voice quality, integrating all deviant components. The term “hoarseness” (H) may also be used for this overall perceptual parameter.

A more extended rating known as GRBAS—including G (grade), R (roughness), B (breathiness), A (asthenia), and S (strain)—is sometimes used for assessing the voice, and this may be encountered in the literature. However, there are no clear pathophysiologic explanations for “asthenia,” which may sound breathy, or “strain,” which also may include roughness.

A scale known as RBH has therefore been developed from the above components of auditory perceptual analyses. For reporting purposes, each component is graded on four points (0, normal or absence of deviance; 1, slight deviance; 2, moderate deviance; 3, severe deviance). The highest score becomes the grade. This is a very simple but reliable way of documenting voice quality. It is subjective, and is best evaluated by speech and language therapy practitioners and phoniatricians.

It is also possible to score RBH on a visual analog scale (VAS), which is a line 100 mm long. Marking a distance on this line reflects the perceived severity. The left end indicates an absence (0 mm) and the right end indicates full expression (100 mm) of any of the deviations. For easier rating, anchoring points indicating mild, moderate, and severe may be provided along the line.

Video stroboscopy: Video laryngostroboscopy is the main clinical tool for the etiological diagnosis of voice disorders. It can also be used to assess the quality of vocal fold vibration and thus the effectiveness of medical or surgical treatments. The basic parameters involved are:

Glottal closure: Insufficient closure can be longitudinal (over the whole length of the glottis and without sufficient adduction), dorsal (posterior triangular chink—occurs in ≈60% of middle-aged healthy women during normal voice effort), ventral, irregular, oval (over the whole length of the glottis, but with a dorsal closure), or hourglass-shaped.

Regularity: Mucosal wave accounts for the physiology of the layered structure of the vocal folds; see ▶ Table 5.1  and ▶ Fig. 5.1.

Symmetry: The “mirror” motion of the two vocal folds. Usually, asymmetry is caused by limited vibratory quality due to a lesion (e.g., diffuse scar, localized cyst, or leukoplakia).

Acoustics: Acoustic parameters provide instrumental and noninvasive measures of vocal function. Perturbation measures (in period and amplitude) and harmonics-to-noise computations have emerged as the most robust measures, and these appear to be capable of determining the basic perceptual elements of voice quality—grade, roughness, and breathiness. Percentage jitter and percentage shimmer are currently used as the basic acoustic measures, computed using a voice sample of a sustained /a:/ at a comfortable frequency and intensity. Jitter is computed as the mean difference between the periods of adjacent cycles divided by the mean period. It is a measurement that is therefore related to the fundamental frequency (F₀). Shimmer is computed as the mean difference between peak-to-peak amplitudes divided by the mean amplitude. Obviously, comparisons of voice quality before and after treatment require the use of similar techniques and materials in both tests.

Aerodynamics: The simplest aerodynamic parameter in voicing is the maximum phonation time (MPT) in seconds. This consists of a prolongation of the vowel /a:/ for as long as possible after maximum inspiration and at a spontaneous, comfortable pitch and loudness. A prior demonstration is necessary, and three trials are required, the longest time being selected.

Voice range profile (VRP): This determines the upper and lower limits of both the pitch range and loudness. The VRP is recorded using specialized software on a computer equipped with a microphone. The patient sits in front of the computer (ideally, in a soundproof room) and says “/a:/” at various pitches and loudness levels. On the monitor, the computer draws a graph of the sounds of the patient’s voice. Pitch (frequency) is measured from left to right, with the lowest-pitched notes at the far left. Loudness (intensity) is measured from bottom to top, with the softest sounds near the bottom. When pitch and loudness are displayed together, the shape of the whole voice recording is often like a football. The range of loud and soft sounds is wide in the comfortable middle of the pitch range and more limited near the higher and lower pitches. The basic acoustic measures include three critical points of the VRP. The highest frequency and the softest intensity—dB(A) at 30 cm—appear to be the most sensitive for changes in voice quality, the latter being related to the phonation threshold pressure. The additional measurement of the lowest frequency makes it possible to compute the pitch range.

Subjective rating by patient: This evaluation of voice is becoming increasingly important in everyday clinical practice. It is the patient who has to live with his or her voice. A voice handicap index can be computed on the basis of a patient’s responses to a carefully selected list of questions that investigates the severity of disability/handicap in everyday social and/or professional life and the possible emotional repercussions of the dysphonia. An easy subjective evaluation can be provided by patient themselves on a double visual analog scale of 100 mm (see above). On the first scale, the impression of the voice quality in the strict sense is marked; on the second scale, the impression of what impact the voice problem has on everyday social and, if relevant, professional life and activities is marked.

A score of “0” (at the extreme left) means a normal voice and no voice-related disability or handicap in everyday life, whereas “100” (at the extreme right) means extreme voice deviance and extreme voice-related disability or handicap in everyday social (and professional) activities, as rated by patients themselves.

5.1.3 Regulatory Voice Disorders

5.1.3.1 Vocal Misuse and Musculoskeletal Tension Dysphonia

Signs and symptoms: The main symptom is vocal fatigue. The voice is loaded but unable to be heard in a given environment (e.g., a classroom). Patients feel a sore throat, pain in the neck, or a lump in the throat. The voice presents with mild-to-moderate hoarseness.

Pathogenesis: Voice generation with disrupted balance of the respiration, phonation, and resonation that are necessary for efficient voice production. Overuse or abusive voice behaviors may lead to organic changes such as vocal nodules, vocal polyps, vocal fold cysts, or contact granulomas. Misuse of extrinsic and intrinsic laryngeal muscles causes tension or pain at the larynx and vocal fatigue.

Diagnosis: Organic changes are described in Chapter 4. In nonorganic disorders, video stroboscopy shows no specific findings, with the exception of a posterior gap in the closed phase of the glottal cycle in most patients. Voice diagnosis generally reveals a breathy voice with mild hoarseness, a reduced MPT, reduced vocal intensity in the VRP, normal jitter, and mild-to-moderate handicap on subjective assessment.

Treatment: In accordance with the history, it has to be decided whether treatment should be conservative in order to achieve the long-term goals desired in the patient’s career.

If a nonorganic voice disorder is obviously due to vocal misuse and muscle tension, a more symptom-orientated voice therapy should be favored. Organic changes should be treated by combining surgery and voice therapy.

5.1.3.2 Psychogenic Voice Disorder

Signs and symptoms: Total inability to speak; whispered speech in cases of conversion aphonia; strained or strangled speech in cases of conversion dysphonia.

Pathogenesis: The voice disorder is a manifestation of psychological disequilibrium—such as anxiety, depression, conversion reaction, or a personality disorder—that is interfering with volitional control over phonation. This may lead to musculoskeletal tension disorders or vocal abuse, which can be observed or retrieved from the patient’s history.

Diagnosis: During video laryngoscopy, regular vocal folds may be visible with normal respiratory movement. When attempting to phonate, the vocal folds approach but do not contact. Organic changes such as vocal nodules, contact granuloma, or ventricular phonation rarely occur as accompanying findings. Voice diagnosis is difficult, as the patient is often unwilling or unable to comply with the tasks it involves.

Treatment: This is carried out by a speech and language therapist or psychotherapist. A patient with psychogenic or conversion aphonia should be treated immediately during the first visit to a voice clinic. Treatments for conversion dysphonia may require 10 to 20 sessions, and further sessions depending on the progress the patient makes. Psychotherapy may also be required.

5.1.3.3 Spasmodic Dysphonia

Clinical features: Adductor spasmodic dysphonia comes with a tight voice quality, abrupt initiation and termination of voicing, a broken staccato speech pattern, and short breaks in speech. In rare cases of abductor spasmodic dysphonia, the glottis opens rather than tightening during speech, resulting in a breathy voice or whispering. Occasionally, there may be features of both types of dystonia. In some patients, the spasmodic dystonia will be part of a wider group of head and neck dystonias.

Pathogenesis: Spasmodic dysphonia is a focal form of dystonia. Dystonia disorders are thought to be due to abnormal functioning in the basal ganglia of the brain. Involuntary excessive contraction of the muscles that bring the vocal folds together affects the flow of air through the vocal folds. The air is pressed through the glottis with strong effort.

Diagnosis: The voice in patients with spasmodic dystonia is characteristic, but because it is so uncommon, the diagnosis is frequently missed or attributed to a functional dysphonia. Key professionals who should be able to recognize the disorder include phoniatricians, speech and language therapists, neurologists, and otolaryngologists. A structural abnormality of the larynx such as nodules, polyps, neoplasms, or inflammation is easily excluded by an otolaryngologist.

There may be associated dystonias affecting the pharynx or other areas within the head and neck region, and a neurological review is particularly useful to identify such disorders.

Treatment: The voice can generally be well-controlled in spasmodic dystonia by injecting botulinum neurotoxin type A into the vocal fold muscles/thyroarytenoid muscles. On occasions where there is an abductor dystonia, injecting the posterior cricoarytenoid can provide effective control. Very small doses of toxin are used and too high a dose will worsen the voice temporarily for a few weeks. Recurrent injections are needed every 3 to 4 months to maintain overall control.

While speech and language therapy may be offered, most patients receiving effective repeated botulinum toxin injections decline this additional support.

Surgery for spasmodic dystonia: Although botulinum neurotoxin (BoNT) remains the gold standard and most commonly used treatment for spasmodic dysphonia there are a number of surgical procedures that have been described. Surgical options are typically reserved when BoNT has not been as effective and/or a more permanent solution is requested. The surgical procedures reported to have been used include: thyroarytenoid muscle myectomy, neurectomy of the thyroarytenoid branch of the recurrent laryngeal nerve, and laryngoplasty procedures.

A thyroplasty type II (or midline lateralization) using a titanium bridge has been used with reported long-term success in Japan. Selective laser thyroarytenoid myoneurectomy has also been used with reported long-term improvements.

However, these operations can have a permanent effect on the patient’s voice. There is currently a lack of evidence in comparing different surgical techniques and the long-term voice outcomes.

For patients with severe head and neck dystonias as well as laryngeal dystonia, deep brain stimulation has been shown to be effective and helpful.

5.1.3.4 Inducible Laryngeal Obstruction

Clinical features: Wheezing or inspiratory stridor due to inappropriate closure of the true vocal folds during respiration.

Pathogenesis: The nature of this disease is not well understood, and its incidence is still unknown. It may occur in patients with asthma; focal laryngeal dystonia; Gerhardt syndrome (congenital laryngeal abductor paralysis); psychogenic, drug-induced laryngeal dystonia; gastroesophageal reflux; or it may be exercise-induced.

Diagnosis: This is made by exclusion. Transnasal fiberoptic endoscopy during an acute attack reveals a pattern of vocal fold adductory and abductory movement consistent with paradoxical movement during repeated tasks such as phonating the vowel /ee/ and sniffing, coughing, panting, or throat-clearing. Spirometry (assessment of pulmonary flow volume loops), arterial blood gases, bronchial challenge testing, and chest radiography are carried out.

Treatment: This consists of psychotherapy, pharmacologic management (to relieve the symptoms), and behavioral management (speech therapy). Botulinum toxin can sometimes be effective.

5.2 Speech Sound and Fluency Disorders

5.2.1 Articulation Disorder

Clinical features: Functional speech disorder is one of several speech sound disorders that can occur in children and persist to adulthood. A child with an articulation disorder has difficulty in learning to make a specific speech sound (e.g., /r/), or a few specific speech sounds, which may include some or all of these: /s/, /z/, /r/, /l/, and /th/. The most common disorder is a lisp (sigmatism).

Causes: Unknown.

Diagnosis: This is made by a speech and language therapist.

Therapy: Treatment is given by a speech and language therapist. In general, the prognosis for the successful treatment of functional speech disorders in children is good.

5.2.2 Phonological Disorder

Clinical features: By the age of 4 years, children with this disorder will show an impaired ability to produce sounds as expected for their developmental level. These children have poor phonological awareness (the ability to recognize and manipulate the sounds and syllables used to compose words) in particular, and poor metalinguistic ability (the capacity to think about and talk about language) generally.

Affected children do not pronounce sounds clearly, or replace one sound with another, e.g., /k/ is replaced by /t/, or /g/ is replaced by /d/: “I’m a dood dirl.” The child has difficulty in learning and organizing all the sounds needed for clear speech, reading, and spelling. Difficulties in speech sound production interfere with academic or occupational achievement, or with social communication.

Pathogenesis: The disorder is more common in boys and affects ≈10% of children under the age of 8 years. Five percent of those above 8 years of age have this disorder. By the age of 17 years, the incidence of phonological disorder is reduced to 0.5% (an estimate, as there are no reliable data). A phonological disorder will occur if the sound is stored wrongly in the child’s mind, or if the sound is actually said incorrectly by the child, or the cognitive processes that correlate storage and articulation are absent or incorrect.

Diagnosis: Assessment by a speech and language therapist helps determine what the particular needs of an individual child are. The child may have:

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  A problem with speech clarity during preschool years, with no subsequent reading and spelling problems.

  
  
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  A problem with speech clarity during preschool years and in early school years, difficulty in learning to read, and difficulties with reading comprehension.

  
  
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  Speech and reading problems as described above, plus difficulty with spelling.

  
  
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  Speech and spelling problems (i.e., no reading difficulties).

  
  
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  Speech clarity problems during preschool years, and difficulties with written expression in elementary school (primary school).

Differential diagnosis: Hearing impairment, delayed speech, mental retardation, and learning disability also lead to language use that is not easily understood.

Treatment: Most children with dyslalia or phonological disorders need speech and language therapy for a long period.

5.2.3 Stuttering

Stuttering is a speech fluency disorder in which speech is interrupted by repeated movements and fixed postures of the speech mechanism. These interruptions may be accompanied by signs of struggle and tension. The speech disruptions involved in stuttering range from mild to severe. Stuttering may also be quite variable within individuals.

The impact of stuttering on everyday life: Someone who stutters may experience extreme frustration and anxiety about speaking. Stuttering interferes with communication and with people’s social interactions, causes embarrassment, prevents attainment of the vocational potential, and may lead to social anxiety or social phobia.

Causes: Stuttering is most likely due to a problem with neural processing (brain activity) that underlies speech production. It appears to be almost entirely confined to speech production. People who stutter are not as a group less intelligent or less well coordinated than those who do not stutter. Adults who stutter are more prone to social anxiety than others. Stuttering is thought to be a physical disorder and is not thought to be caused by psychological factors such as nervousness or stress, or parenting practices, or the way parents communicate with their children when they are young. The learning theory assumes that stuttering results from an effort not to stutter. The breakdown theory claims that the coordination of the anatomical structures involved in speech is affected. The demands and capacities model regards stuttering as a result of high demands on fluent speech with inadequate motor, cognitive, and linguistic abilities on the part of the speaker. There is a genetic element in the etiology, but the precise nature of the inheritance is at present unknown.

Persistent developmental stuttering: About 5% of children start to stutter, usually during the third and fourth years of life. The onset typically occurs as children are starting to put words together into short sentences. The onset of stuttering can be gradual or sudden, and at onset the severity of stuttering ranges from mild to severe. In a few cases, the onset can be so sudden and severe that parents think their child has a serious illness.

Symptoms:

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  Repeating sounds, syllables, or monosyllabic words: “I… I… I… wanna …” or “Where … where … where is…?” or “W – W – W – Where are you going?”

  
  
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  Blocks: holding the lips and tongue in one position for brief periods (when attempting to start a word, as in “…………………can I have a drink?”)

  
  
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  Sound prolongation, as in “Wwwwwwwwhere is my drink?”

  
  
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  Covert stuttering: the speaker produces several interjections in order to say the word “around” smoothly (“I’ll meet you—um umyou know like—around six o’clock”), because he or she expects to have difficulty in smoothly joining the word “you” with the word “around.”

  
  
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  Unusual facial and body movements associated with the effort to speak.

Natural recovery: Many children recover from stuttering naturally, although the exact rate of recovery and the average time taken to recover are not known. It seems that more girls recover naturally than boys, and that having a family history of recovery from stuttering may increase a child’s chances of recovering naturally. The chances of recovery seem to be best shortly after the onset of the condition. However, at present, it is not possible to say whether an individual child will recover naturally or will require treatment.

Therapy: Developmental stuttering is often treated by providing parents with information about how to restructure the child’s speaking environment in order to reduce episodes of stuttering. Parents are often urged to:

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  Provide a relaxed home environment that provides ample opportunities for the child to speak. Setting aside specific times when the child and parent can speak free of distractions is often helpful.

  
  
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  Refrain from criticizing the child’s speech or reacting negatively to the child’s disfluencies. Parents should avoid punishing the child for any disfluency or asking the child to repeat stuttered words until they are spoken fluently.

  
  
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  Resist the urge to encourage the child to perform verbally for people.

  
  
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  Listen attentively to the child when he or she speaks.

  
  
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  Speak slowly and in a relaxed manner. If a parent speaks this way, the child will often speak in the same slow, relaxed manner.

  
  
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  Wait for the child to say the intended word. Do not try to complete the child’s thoughts.

  
  
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  Talk openly to the child about stuttering if he or she brings up the subject.

A speech evaluation is recommended for children who stutter for more than 6 months or for those whose stuttering is accompanied by struggle behaviors.

Two main therapeutic strategies have been developed. Fluency shaping focuses on relearning how to speak or unlearning faulty ways of speaking. Following the nonavoidance strategy, the stutterer (1) identifies the symptoms, (2) reduces anxiety, (3) releases blocks by modification, and (4) stabilizes speech by applying these methods. The psychological side effects of stuttering should also be addressed. Any of a variety of treatments may improve stuttering to some degree, but there is at present no cure for stuttering. Stuttering therapy, however, may help prevent developmental stuttering from becoming a lifelong problem.

Medications or drugs which affect brain function often have side effects that make them difficult to use for long-term treatment. Electronic devices that help an individual to control fluency may be troublesome in most speaking situations and are therefore often abandoned by individuals who stutter.

Unconventional methods of stuttering therapy also exist. It is a good policy to check the credentials, experience, and goals of the person offering treatment and to avoid working with anyone who promises a “cure” for stuttering.

5.3 Language

5.3.1 Normal Language Development

Milestones for normal language development are provided in ▶ Table 5.2 . These are helpful for comparing a child’s developmental stage with what can be expected at various ages.

If a baby is not babbling or imitating any sounds by the age of 7 months, it may mean there is a problem with hearing or speech development. Babies with partial hearing loss still can be startled by loud noises or will turn the head toward them, and babies may even respond to their parents’ voices. But they will have difficulty in imitating speech. A newborn’s hearing should be checked by hearing screening. Later on, observations by parents are an early warning system. A baby should be referred to a children’s hearing specialist (pediatric audiologist) if there is any suspicion.

5.3.2 Developmental Language Disorder

Language acquisition is the primary area of concern as the child grows and develops. There are no obvious related causes such as hearing loss or low intelligence quotient (IQ) for the condition known as developmental language disorder (DLD; this is a precise name for other terms that are also used, such as language delay or developmental dysphasia). The condition may be genetic. The incidence of DLD in children of kindergarten age may be as high as 7% to 8%, and DLD is known to persist into adulthood.

Clinical features: DLD is a language disorder. This means that the child has difficulty in understanding and using words in sentences. Both receptive and expressive skills are typically affected. Late talking may be a sign of disability. Five-year old children with DLD sound approximately 2 years younger than their age. Children who do not ask questions or tell adults what they want may have a communication disorder. Children with DLD may not produce any words until they are nearly 2 years old. At the age of 3 years, they may talk, but cannot be understood. As they grow, they struggle to learn new words, make conversation, and sound coherent. An incomplete understanding of verbs is a sign of DLD. Typical errors include dropping the -s off present-tense verbs and asking questions without the usual “be” or “do” verbs, or dropping the past tense ending from verbs. DLD affects a child’s academic achievement, and 40% to 75% of these children have problems in learning to read.

IQ, hearing, emerging motor skills, social-emotional development, and the child’s neurological profile are all normal.

Diagnosis: The signs of DLD are present by the age of 3 years. The Rice-Wexler Test of Early Grammatical Impairment can identify specific gaps in a child’s language abilities. It can be used with children aged 3 to 8 years.

Treatment: Early identification and intervention during preschool years is time well spent to minimize possible academic risks. Children with DLD need extra opportunities to talk and listen. Interactions with other children are especially difficult, as they are less supportive and patient than adults. The focus of class activities may be role-playing, sharing time, or hands-on lessons with new, interesting vocabulary. This kind of preschool will encourage interaction between children, and will build rich layers of language experience. Equipping a child for success at ages 3 and 4 years will lead to positive experiences in the kindergarten. Parents can also send their preschool child to a speech and language therapist.

Differential diagnosis: DLDs are often associated with hearing loss that may have gone unrecognized. Several other disabilities, such as intellectual disability, autism spectrum disorder, and cerebral palsy may be associated with communication difficulties, but these are not classified as DLD. Speech sound or fluency disorders are different from language disorders. Such children make errors in pronouncing words, or may stutter.

5.3.3 Aphasia

Aphasia is a communication disorder that occurs after language has been developed, usually in adulthood. Not simply a speech disorder, aphasia can affect the ability to comprehend the speech of others, as well as the ability to read and write. In most instances, intelligence per se is not affected.

Clinical features: To a variable degree, symptoms include deficiencies in speech production, auditory language comprehension, and phonemic, morphological, and semantic paraphasias. Most experts in aphasia recognize that aphasia varies along two major dimensions, auditory comprehension ability and fluency of speech output, leading to the concept of nonfluent and fluent types of aphasia.

Nonfluent aphasia (Broca aphasia): Disordered fluency of speech output is characterized by slow, labored speech with limited output and prosody. Individuals have difficulty in using the substantive words of their native language and in producing grammatical sentences. Verbs and prepositions are disproportionately affected. Speech errors occur mostly at the level of speech sounds, producing sound transpositions and inconsistencies. Auditory comprehension is only minimally affected. Reading abilities parallel comprehension. There is an inability to repeat what someone else says. Broca aphasia is quite likely to co-occur with motor problems. Hemiplegia on the side of the body opposite the side of brain damage affects walking and writing. Writing problems parallel speech output, but there are diminished abilities if the arm used for writing is paralyzed.

Fluent aphasia (Wernicke aphasia): Individuals with fluent aphasia have problems in comprehending and monitoring their own speech. They are verbose and use inappropriate and jargon words. There is a disproportionate difficulty in understanding spoken and written language. Reading and writing are impaired in similar ways to auditory comprehension and speech output. The patients’ comprehension difficulties make them unable to repeat words spoken by others. Individuals with fluent aphasia seldom have coexisting difficulty with the mechanics of speech, arm use, or walking.

In anomic aphasia, individuals have problems with naming.

Conduction aphasia is due to damage to the neural links between the posterior and anterior speech areas, which makes it quite difficult for these individuals to correct the errors they hear themselves making and affects their ability to repeat the speech of others.

Pathogenesis: The language zone in the brain includes the portion of the frontal, temporal, and parietal lobes surrounding the Sylvian fissure and structures deep to these areas ( ▶ Fig. 5.5). Aphasia is most frequently caused by damage to the cerebral cortex of the left hemisphere of the brain, which is dominant in language processing and language skills. Hemispheric laterality is reversed in a small minority of patients: this feature is seen in about half of left-handed individuals and in a few right-handed persons. In these cases, right-hemisphere damage is the cause of aphasia. Aphasia occasionally results from damage to subcortical structures such as the basal ganglia or thalamus, which has rich interconnections with the cerebral cortex.

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