Classification of Speech Disorders

Classification of Speech Disorders including Speech Sound, Fluency and Voice Disorders

1. Classification of Speech Disorders Dr.  Shazia  Tahira (Audiology & Speech-Language Pathology)

2. Speech & Speech Disorders Speech  refers specifically to sounds produced by the oral mechanism, including the lips, tongue, vocal cords, and related structures.  Speech Disorders refer to problems in producing the sounds of speech or with the quality of voice.  People with speech disorders may: not say sounds clearly have a hoarse or raspy voice repeat sounds or pause when speaking

3. Language Disorders Are Distinct From Speech Disorders Language  refers to the code, or a system of words and symbols—written, spoken or expressed with gestures and body language—that is used to communicate meaning and for transforming unobservable mental events, such as thoughts and memories, into events that can be perceived by other people. Language Disorders are an impairment of either understanding linguistic information (Receptive Language) or the ability to use and share linguistic information (Expressive Language) and are not related with speech production.

4. Classification of Speech Disorders

5. Speech Sound Disorders A Speech Sound Disorder  ( SSD ) is a speech disorder in which some speech sounds (called phonemes) are either not produced, not produced correctly, or are not used correctly.    Speech sound disorders can be organic or functional in nature. Organic Speech Sound Disorders  result from an underlying motor/neurological, structural, or sensory/perceptual cause. Functional Speech Sound Disorders   are idiopathic—they have no known cause.

6. Organic and Functional Speech Sound Disorders Organic Speech Sound Disorders include those resulting from Motor/Neurological Disorders  (e.g., childhood apraxia of speech and dysarthria) Structural Abnormalities (e.g., cleft lip/palate and other structural deficits or anomalies) Sensory/Perceptual Disorders   (e.g., hearing impairment). Functional Speech Sound Disorders include those related to the  Motor Production of Speech Sounds (articulation disorders or phonetic disorders) Linguistic Aspects of Speech Production (phonological disorders or phonemic disorders)

7. Articulation Disorders and Phonological Disorders Articulation disorders (Phonetic Disorders)   focus on errors (e.g., omissions, substitutions, and distortions) in production of individual speech sounds. Omissions:(bo for boat) Substitutions: (wabbit for rabbit)  Distortions: (shlip for sip) Phonological Disorders  (Phonemic Disorders)  focus on predictable, rule-based errors (e.g., fronting, stopping, and final consonant deletion) that affect more than one sound. Phonological disorders  are considered both speech and language disorders because it is the language system that is affected but they are also a speech sound disorders in that the errors relate to use of phonemes (speech sounds). This makes it different from  specific language impairment,  which are primarily disorders of the morphology (word structure), syntax (grammar), semantics (meaning) and   pragmatics (usage) of language rather than the sound system. It is often difficult to clearly differentiate between articulation and phonological disorders; therefore, many researchers and clinicians prefer to use the broader term "speech sound disorder" when referring to speech errors of unknown cause.

8. Articulation Disorder (A Speech Sound Disorder) “Be  vewwy   vewwy  quiet…I’m hunting  wabbits .”

9. Apraxia of Speech and Dysarthria Apraxia of Speech (AOS)  or   Acquired Apraxia of Speech  is an acquired oral motor speech disorder affecting an individual's ability to translate conscious speech plans into motor plans, which results in limited and difficult speech ability. AOS affects willful or purposeful movement patterns and usually also affects automatic speech. Apraxia of speech can be caused by impairment to parts of the brain that control muscle movement and speech. Individuals with AOS have difficulty connecting speech messages from the brain to the mouth. AOS is a loss of prior speech ability resulting from a brain injury such as a stroke, trauma, progressive illness or tumor. AOS can affect a person at any age although it mostly typically occurs in adults. Childhood Apraxia of Speech (CAS)  is an inability to utilize motor planning to perform movements necessary for speech during a child's language learning process. The cause may be genetics and sometimes there is no observable cause. Although the causes may differ between AOS and CAS, the main characteristics and treatments are similar. Dysarthria is a motor  speech disorder characterized by difficulty articulating sounds. The difficulty in articulation does not occur in planning the motor movement, as happens with Apraxia of Speech. Instead, dysarthria is caused by inability in or weakness of the muscles in the mouth, face, and respiratory system. Dysarthria can result from congenital conditions, or it can be acquired at any age as the result of neurological injury, disease, or disorder.

10. The muscles involved in speech need to move in a coordinated manner in order to produce Speech Sounds. These movements are controlled by brain and are also dependent upon speech muscles strength In Apraxia, the speech muscles are normal and of normal strength but the brain signals that control movements of these muscles during speech become abnormal In Dysarthria, the brain signals that control movement of speech muscles during speech are normal but speech muscles are weak and not able to move

11. Fluency Disorders Fluency is the aspect of speech production that refers to continuity, smoothness, rate, and effort.  Fluency disorders are difficulties with the rhythm and timing of speech characterized by hesitations, repetitions, or prolongations of sounds, syllables, words, or phrases. Common fluency disorders include: Stuttering : rapid-fire repetitions of consonant or vowel sounds especially at the beginning of words, prolongations, hesitations, interjections, and complete verbal blocks Cluttering : excessively fast and jerky speech

12. Stuttering (A Fluency Disorder) “I w-w-w-want a job.” ​

13. Voice Disorders      Voice disorders are problems with the quality or use of one's voice resulting from disorders in the larynx. Voice disorders are characterized by abnormal production and/or absences of vocal quality, pitch, loudness, resonance, and/or duration.     Voice Disorders are classified as: Organic  — voice disorders that are physiological in nature Functional  — voice disorders when the physical structure is normal 

14. Organic and Functional Voice Disorders Organic voice disorders are physiological in nature and result from alterations in respiratory, laryngeal, or vocal tract mechanisms Structural   — organic voice disorders that result from physical changes in the voice mechanism (e.g., alterations in vocal fold tissues such as edema or vocal nodules; structural changes in the larynx due to aging) Neurogenic  — organic voice disorders that result from problems with the central or peripheral nervous system innervation to the larynx that affect functioning of the vocal mechanism (e.g., vocal tremor, spasmodic dysphonia, or paralysis of vocal folds) Functional voice disorders result from improper or inefficient use of the vocal mechanism when the physical structure is normal (e.g., vocal fatigue; muscle tension dysphonia or aphonia;  diplophonia ; ventricular phonation)

15. Prevalence of Speech Disorders in USA According to NIDCD (National Institute of Deafness and other Communication Disorders) Nearly 1 in 12 (7.7 percent) U.S. children ages 3-17 has had a disorder related to voice, speech, language, or swallowing in the past 12 months 5 percent of U.S. children ages 3-17 have a speech disorder that lasted for a week or longer during the past 12 months.

16. The prevalence of speech sound disorders (namely, articulation disorders or phonological disorders) in young children is 8 to 9 percent. By the first grade, roughly 5 percent of children have noticeable speech disorders, including stuttering, speech sound disorders, and dysarthria; the majority of these speech disorders have no known cause. More than three million Americans (about one percent) stutter. Stuttering can affect individuals of all ages, but occurs most frequently in young children between the ages of 2 and 6. Boys are two to three times more likely than girls to stutter. Although most children who stutter outgrow the condition while young, as many as one in four will continue to stutter for the rest of their lives, a condition known as persistent developmental stuttering. An estimated 17.9 million U.S. adults ages 18 or older, or 7.6%, report having had a problem with their voice in the past 12 months. Approximately 9.4 million (4.0%) adults report having a problem using their voice that lasted one week or longer during the last 12 months. 1.4 percent of U.S. children have a voice disorder that lasted for a week or longer during the past 12 months.

17. Prevalence of Speech Disorders in UK According to a research by Geoff Lindsay and Steve Strand: Speech, language, and communication needs comprised the third most prevalent type of Special Educational Needs (SEN) with 15.7% of those with SEN having Speech, Language, and Communication Needs (SLCN) as their primary SEN at School Action Plus or above special educational needs support.  Only students with moderate learning difficulties (MLD: 24.3%) and behavioral, emotional, and social difficulties (BESD: 23.7%) were more prevalent than speech, language and communication needs (15.7%) in special educational needs support. According to Talking Point UK, over one million children in the UK have some kind of speech language and communication needs.

18. Prevalence of Speech Disorders in Pakistan A survey conducted in Karachi to gauge the number of those affected elaborated the picture. It concluded that an estimated over 2.2 million individuals in an overall population of over 16 million suffered from speech, language, swallowing and/or hearing disorders. According to Amina Siddiqui, Principle, Ziauddin College of Speech Language and Hearing Sciences, 14 percent of total population in Pakistan is affected by speech and language disorder.

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