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Voice Statistics
Source: Compiled from fact sheets produced by the National Institute on Deafness and Other Communication Disorders (NIDCD).
- Approximately 7.5 million people in the United States have trouble using their voices.
- Spasmodic dysphonia (a voice disorder caused by involuntary movements of one or more muscles of the larynx or voice box) can affect anyone. The first signs of this disorder are found most often in individuals between 30 and 50 years of age. More women appear to be affected by spasmodic dysphonia than men.
- Laryngeal papillomatosis is a rare disease consisting of tumors that grow inside the larynx (voice box), vocal cords, or the air passages leading from the nose into the lungs. It is caused by the human papilloma virus (HPV). Although scientists are uncertain how people are infected with HPV, they have identified more than 60 types of HPVs. Between 60 and 80 percent of laryngeal papillomatosis cases occur in children, usually before the age of three.
- A cleft palate is the fourth most common birth defect, affecting approximately 1 of every 700 live births. Velocardiofacial syndrome (which can include a cleft palate, as well as heart defects, a characteristic facial appearance, minor learning problems, and speech and feeding problems) occurs in approximately 5 to 8 percent of children born with a cleft palate. It is estimated that over 130,000 individuals in the United States have this syndrome.
Voice Summary Report
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Voice (or vocalization) is the sound produced by humans and other vertebrates using the lungs and the vocal folds in the larynx, or voice box. Voice is not always produced as speech, however. Infants babble and coo, animals bark, moo, whinny, growl, and meow, and adult humans laugh, sing, and cry. Voice is generated by airflow from the lungs as the vocal folds are brought close together. When air is pushed past the vocal folds with sufficient pressure, the vocal folds vibrate. If the vocal folds in the larynx did not vibrate normally, speech could only be produced as a whisper. Your voice is as unique as your fingerprint. It helps define your personality, mood, and health.
Approximately 7.5 million people in the United States have trouble using their voices. Disorders of the voice involve problems with pitch, loudness, and quality. Pitch is the highness or lowness of a sound based on the frequency of the sound waves. Loudness is the perceived volume (or amplitude) of the sound, while quality refers to the character or distinctive attributes of a sound. Many people who have normal speaking skills have great difficulty communicating when their vocal apparatus fails. This can occur if the nerves controlling the larynx are impaired because of an accident, a surgical procedure, a viral infection, or cancer.
Speech Statistics
Source: Compiled from fact sheets produced by the National Institute on Deafness and Other Communication Disorders (NIDCD).
- The prevalence of speech sound disorder in young children is 8 to 9 percent. By the first grade, roughly 5 percent of children have noticeable speech disorders; the majority of these speech disorders have no known cause.
- Usually by 6 months of age an infant babbles or produces repetitive syllables such as "ba, ba, ba" or "da, da, da." Babbling soon turns into a type of nonsense speech called jargon that often has the tone and cadence of human speech but does not contain real words. By the end of their first year, most children have mastered the ability to say a few simple words. By 18 months of age most children can say 8 to 10 words and, by age 2, are putting words together in crude sentences such as "more milk." At ages 3, 4, and 5 a child's vocabulary rapidly increases, and he or she begins to master the rules of language.
- It is estimated that more than 3 million Americans stutter. Stuttering affects individuals of all ages but occurs most frequently in young children between the ages of 2 and 6 who are developing language. Boys are 3 times more likely to stutter than girls. Most children, however, outgrow their stuttering, and it is estimated that fewer than 1 percent of adults stutter.
- Autism is one of the most common developmental disabilities, affecting individuals of all races and ethnic and socioeconomic backgrounds. Current estimates suggest that approximately 400,000 individuals in the United States have autism. Autism is 3 to 4 times more likely to affect boys than girls and occurs in individuals of all levels of intelligence. Approximately 75 percent are of low intelligence while 10 percent may demonstrate high intelligence in specific areas such as math.
Speech Summary Report
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Humans express thoughts, feelings, and ideas orally to one another through a series of complex movements that alter and mold the basic tone created by voice into specific, decodable sounds. Speech is produced by precisely coordinated muscle actions in the head, neck, chest, and abdomen. Speech development is a gradual process that requires years of practice. During this process, a child learns how to regulate these muscles to produce understandable speech.
However, by the first grade, roughly 5 percent of children have noticeable speech disorders; the majority of these speech disorders have no known cause. One category of speech disorder is fluency disorder, or stuttering, which is characterized by a disruption in the flow of speech. It includes repetitions of speech sounds, hesitations before and during speaking, and the prolonged emphasis of speech sounds. More than 15 million individuals in the world stutter, most of whom began stuttering at a very early age. The majority of speech sound disorders in the preschool years occur in children who are developing normally in all other areas. Speech disorders also may occur in children who have developmental disabilities.
Children with specific speech sound disorders, which has also been termed articulation disorder or phonological disorder, have clinically significant difficulties producing the speech sounds of their language expected for their age. The extent of these patterns of errors will affect the intelligibility of their speech to some degree and in some cases rendering the speech unitelligible to those unfamiliar with the child. Two recent publications provide summaries of prevalence estimates of this condition (Law et al. 2000; Shriberg, Tomblin, and McSweeny 1999). All these estimates have focused on children in the early school years and the prevelance estimates range from 2 percent among the oldest children who were 8 years old, to 24.6 percent among the youngest who were 5 years old. Much of this variability can be attributed to different diagnostic standards. The median prevalence estimate across these studies falls in the range of 8 to 9 percent. These studies all showed a greater rate of impairment in boys than girls with male to female ratios ranging from 1.5 to 2.4. Speech sound disorders have been shown to occur with SLI, particularly among children referred for clinical services. Risk factors for speech sound disorders consist of family histories of speech sound disorder (Lewis, Ekelman, and Aram 1989) and chronic otitis media (Shriberg LD et al. 2000).
Language Statistics
Source: Compiled from fact sheets produced by the National Institute on Deafness and Other Communication Disorders (NIDCD).
- Between 6 and 8 million people in the United States have some form of language impairment.
- Research suggests that the first 6 months are the most crucial to a child's development of language skills. For a person to become fully competent in any language, exposure must begin as early as possible, preferably before school age.
- Anyone can acquire aphasia (a loss of the ability to use or understand language), but most people who have aphasia are in their middle to late years. Men and women are equally affected. It is estimated that approximately 80,000 individuals acquire aphasia each year. About 1 million persons in the United States currently have aphasia.
- More than 160 cases of Landau-Kleffner syndrome (LKS)–a childhood disorder involving loss of the ability to understand and use spoken language–have been reported from 1957 through 1990. Approximately 80 percent of children with LKS have one or more epileptic seizures that usually occur at night. Most children outgrow the seizures, and electrical brain activity on the EEG usually returns to normal by age 15.
Language Summary Report
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Language is the expression of human communication through which knowledge, belief, and behavior can be experienced, explained, and shared. This sharing is based on systematic, conventionally used signs, sounds, gestures, or marks that convey understood meanings within a group or community. Recent research identifies "windows of opportunity" for acquiring language--written, spoken, or signed--that exist within the first few years of life.
Between 6 and 8 million individuals in the United States have some form of language impairment. Disorders of language affect children and adults differently. For children who do not use language normally from birth, or who acquire an impairment during childhood, language may not be fully developed or acquired. Many children who are deaf in the United States use a natural sign language known as American Sign Language (ASL). ASL shares an underlying organization with spoken language and has its own syntax and grammar. Many adults acquire disorders of language because of stroke, head injury, dementia, or brain tumors. Language disorders also are found in adults who have failed to develop normal language skills because of mental retardation, autism, hearing impairment, or other congenital or acquired disorders of brain development.
Primary or Specific Language Impairments (SLI) are diagnosed in children who have clinically significant impairments in their development of spoken language in the absence of sensory or neurodevelopmental disorders. Spoken language in this case includes the ability to understand words, sentences, and connected speech as well as the ability to express messages using appropriate vocabulary, grammar, and discourse. Standards for the diagnosis of SLI vary and therefore prevalence estimates across studies vary accordingly. Variation in prevalence also appears to be affected by a pattern of recovery for many children during the early preschool years. Much greater stability over age is seen in children during the school years.
Law et al. (2000) have reviewed studies estimating prevalence of SLI during the preschool and early school years. The typical range of prevalence estimates was between 2% and 8% with an overall median prevalence of 5.95%. Most studies reported a greater prevalence of SLI in boys than girls. The male to female sex ratios varied from .98:1 to 2.30:1. Risk factors for SLI have been found to concentrate on family factors (Tomblin, Smith, and Zhang 1997; Tomblin 1992). Limited parental education, and parental history of speech, language, and/or learning problems have been found to be associated with elevated rates of SLI (Bishop 2001; Bishop 2001; Stromswold 1998). In contrast, breast feeding has been shown to serve as a protective factor even in the context of parental education. Reading impairments have been widely shown to be strongly associated with SLI (Catts et al. 2001; Catts 1993).
Books and Articles
- Bishop DVM (2001) Genetic and environmental risks for specific language impairment in children. Philosophical Transactions of the Royal Society of London Series B-Biological Sciences 356 (1407):369-380.
- Catts H et al (2001) Estimating the risk of future reading difficulties in kindergarten children: A research-based model and its clinical implementation. Language Speech and Hearing Services in Schools 32:38-50.
- Catts HW (1993) The relationship between speech-language impairments and reading disabilities. Journal of Speech & Hearing Research 36 (5):948-58.
- Law J et al (2000) Prevalence and natural history of primary speech and language delay: findings from a systematic review of the literature. International Journal of Language " Communication Disorders 35:165-188.
- Lewis BA, Ekelman BL, and Aram DM (1989) A familial study of severe phonological disorders. Journal of Speech and Hearing Research 32 (4):713-724.
- Shriberg LD et al (2000) Risk for speech disorder associated with early recurrent otitis media with effusion: Two retrospective studies. Journal of Speech-Language-Hearing Research 43:79-99.
- Shriberg LD, Tomblin JB, and McSweeny JL (1999) Prevalence of speech delay in 6-year-old children and comorbidity with language impairment. J.Speech Lang Hear.Res. 42 (6):1461-1481.
- Stromswold K (1998) Genetics of spoken language disorders. Hum Biol 70 (2):297-324.
- Tomblin JB (1992) Risk factors associated with specific language disorder. In Wolraich M, Routh DK (eds) Developmental and behavioral pediatrics. Philadelphia: Jessica Kingsley Publishers.
- Tomblin JB, Smith E, and Zhang X (1997) Epidemiology of specific language impairment: Prenatal and perinatal risk factors. Journal of Communication Disorders 30:325-344.
More Information
For more items on these and other topics in human communication and its disorders, do your own search. Some search strategies give you more information than you are looking for and others are too narrow. You will want to adapt the strategy for your particular needs, but to get you started, go to the NLM PubMed and paste in the search topic you have chosen. Be sure to notice how many entries the search will provide, before trying to print them. These searches have been limited by years, but you may want to broaden them.
Alzheimer's Disease - alzheimer's disease[mh] & (ep[sh] OR incidence[mh] OR prevalence[mh])& ( communications disorders [mh] OR deafness[mh] OR "hearing impairment" OR "hearing disorders"[mh] OR "sensation disorders"[mh]) - limits Publication Date from 1997, English ; alzheimer's disease[mh] & (ep[sh] OR incidence[mh] OR prevalence[mh])& ( communications disorders [mh] OR deafness[mh] OR "hearing impairment" OR "hearing disorders"[mh] OR "sensation disorders"[mh]) - limits Publication Date from 1992, English, Reviews
Apraxia - "Apraxias"[MESH] & (ep[sh] OR incidence[mh] OR prevalence[mh]) Attention Deficit Disorder ]) - limits Publication Date from 1997, English ; "Apraxias"[MESH] & (ep[sh] OR incidence[mh] OR prevalence[mh]) - limits Publication Date from 1992, English, Reviews
Autism - autism[mh] & (ep[sh] OR incidence[mh] OR prevalence[mh])& ( communications disorders [mh] OR deafness[mh] OR "hearing impairment" OR "hearing disorders"[mh] OR "sensation disorders"[mh]) - limits Publication Date from 1997, English ;autism[mh] & (ep[sh] OR incidence[mh] OR prevalence[mh])& ( communications disorders [mh] OR deafness[mh] OR "hearing impairment" OR "hearing disorders"[mh] OR "sensation disorders"[mh]) - limits Publication Date from 1992, English, Reviews
Brain Tumor - brain neoplasms[mh] & (ep[sh] OR prevalence[mh] OR incidence[mh]) & ( communications disorders [mh] OR deafness[mh] OR "hearing impairment" OR "hearing disorders"[mh] OR "sensation disorders"[mh]) - limits Publication Date from 1997, English ; brain neoplasms[mh] & (ep[sh] OR prevalence[mh] OR incidence[mh]) & ( communications disorders [mh] OR deafness[mh] OR "hearing impairment" OR "hearing disorders"[mh] OR "sensation disorders"[mh]) limits Publication Date from 1992, English, Reviews
Cleft Lip and Palate - ("cleft palate"[MESH] OR "cleft lip"[MESH] ) & (ep[sh] OR incidence[mh] OR prevalence[mh])& ( communications disorders [mh] OR deafness[mh] OR "hearing impairment" OR "hearing disorders"[mh] OR "sensation disorders"[mh]) - limits Publication Date from 1997, English ; ("cleft palate"[MESH] OR "cleft lip"[MESH] ) & (ep[sh] OR incidence[mh] OR prevalence[mh])& ( communications disorders [mh] OR deafness[mh] OR "hearing impairment" OR "hearing disorders"[mh] OR "sensation disorders"[mh]) - limits Publication Date from 1992, English, Reviews
Dysarthria - (dysarthria [mh]) & (ep[sh] OR incidence[mh] OR prevalence[mh] - limits Publication Date from 1997, English ; (dysarthria [mh]) & (ep[sh] OR incidence[mh] OR prevalence[mh] - limits Publication Date from 1992, English, Reviews
Dyslexia - (dyslexia [mh]) & (ep[sh] OR incidence[mh] OR prevalence[mh] - limits Publication Date from 1997, English ; (dyslexia [mh]) & (ep[sh] OR incidence[mh] OR prevalence[mh] - limits Publication Date from 1992, English , Reviews
Dysphagia - (dysphagia [mh]) & (ep[sh] OR incidence[mh] OR prevalence[mh] AND ( communications disorders [mh] OR deafness[mh] OR "hearing impairment" OR "hearing disorders"[mh] OR "sensation disorders"[mh]) - limits Publication Date from 1997, English ; (dysphagia [mh]) & (ep[sh] OR incidence[mh] OR prevalence[mh] AND ( communications disorders [mh] OR deafness[mh] OR "hearing impairment" OR "hearing disorders"[mh] OR "sensation disorders"[mh]) - limits Publication Date from 1992, English, Reviews
Dystonia - dystonia/ep [majr] OR dystonia [majr] & (incidence [mh] OR prevalence [mh]). - limits Publication Date from 1997, English dystonia/ep [majr] OR dystonia [majr] & (incidence [mh] OR prevalence [mh]). - limits Publication Date from 1992, English, Reviews
Landau Kleffner Syndrome "Landau-Kleffner Syndrome"[MESH] & (ep [sh] OR incidence [mh] OR prevalence [mh]). limits Publication Date from 1997, English. No reviews available
Language Development -- (language development [mh:noexp] & ep [sh]. ]). limits Publication Date from 1997, English. (language development [mh:noexp] & ep [sh]. - limits Publication Date from 1992, English, Reviews
Neural Stimulation - electrical stimulation [mh] & neural [tw] & (communication disorders [mh] OR language disorders [mh] OR speech disorders [majr] OR hearing disorders [majr] OR voice disorders [majr]). limits Publication Date from 1997, English electrical stimulation [mh] & neural [tw] & (communication disorders [mh] OR language disorders [mh] OR speech disorders [majr] OR hearing disorders [majr] OR voice disorders [majr]). - limits Publication Date from 1992, English, Reviews
Reading Development - (communication disorders [majr] OR hearing disorders [majr] OR speech disorders [majr] OR language disorders [majr] OR voice disorders [majr]) & reading [mh] & (ep [sh] OR incidence [mh] OR prevalence [mh]) . limits Publication Date from 1997, English.
Reading Disorders - ("Dyslexia"[MESH]OR "reading disorder*") AND (epidemiology[mh] OR incidence[mh] OR prevalence[mh]) Limits: Publication Date from 1997, English; ("Dyslexia"[MESH]OR "reading disorder*") AND (epidemiology[mh] OR incidence[mh] OR prevalence[mh]) Limits: Publication Date from 1992, English, Review
Spasmodic Dysphonia - "spasmodic dysphonia" AND (epidemiology[mh] OR incidence[mh] OR prevalence[mh]) Limits: Publication Date from 1997, English
Speech - "speech"[MESH] AND (disorder* OR "communication disorders"[mh]) AND (epidemiology[mh] OR incidence[mh] OR prevalence[mh]) Limits: Publication Date from 1997, English; "speech"[MESH] AND (disorder* OR "communication disorders"[mh]) AND (epidemiology[mh] OR incidence[mh] OR prevalence[mh]) Limits: Publication Date from 1992, English, Review
Speech and Language Disorders - ("speech disorders"[MESH] OR "language disorders"[MESH]) AND (epidemiology[mh] OR incidence[mh] OR prevalence[mh]) Limits: Publication Date from 1997, English; ("speech disorders"[MESH] OR "language disorders"[MESH]) AND (epidemiology[mh] OR incidence[mh] OR prevalence[mh]) Limits: Publication Date from 1992, English, Review
Stroke - "Cerebrovascular Accident"[MESH] AND (epidemiology[mh] OR incidence[mh] OR prevalence[mh]) AND ("communications disorders" [mh] OR deafness[mh] OR "hearing impairment" OR "sensation disorders"[mh]) Limits: Publication Date from 1997, English; "Cerebrovascular Accident"[MESH] AND (epidemiology[mh] OR incidence[mh] OR prevalence[mh]) AND ("communications disorders" [mh] OR deafness[mh] OR "hearing impairment" OR "sensation disorders"[mh]) Limits: Publication Date from 1992, English, Review
Swallowing Disorders - (degultition[mh] OR "swallowing disorder*") AND (epidemiology[mh] OR incidence[mh] OR prevalence[mh]) Limits: Publication Date from 1997, English
Tourette Syndrome - "tourette syndrome"[MESH] AND (epidemiology[mh] OR incidence[mh] OR prevalence[mh] OR "occupational exposure"[mh] OR "environmental exposure"[mh]) Limits: Publication Date from 1997, English; "tourette syndrome"[MESH] AND (epidemiology[mh] OR incidence[mh] OR prevalence[mh] OR "occupational exposure"[mh] OR "environmental exposure"[mh]) Limits: Publication Date from 1992, English, Review
Tongue - "tongue"[MESH] AND (epidemiology[mh] OR incidence[mh] OR prevalence[mh] OR "occupational exposure"[mh] OR "environmental exposure"[mh]) Limits: Publication Date from 1997, English, Human; "tongue"[MESH] AND (epidemiology[mh] OR incidence[mh] OR prevalence[mh] OR "occupational exposure"[mh] OR "environmental exposure"[mh]) Limits: Publication Date from 1992, English, Review, Human
Trauma Research - "Wounds and Injuries"[MESH] AND (research[mh] OR "trauma research") AND (epidemiology[mh] OR incidence[mh] OR prevalence[mh] OR "occupational exposure"[mh] OR "environmental exposure"[mh]) AND (ear OR nose OR throat OR eye OR eyes OR communication OR deafness or "hearing impairment") Limits: Publication Date from 1997, English; ("Wounds and Injuries"[MESH] OR trauma) AND research[mh] AND (epidemiology[mh] OR incidence[mh] OR prevalence[mh] OR "occupational exposure"[mh] OR "environmental exposure"[mh]) Limits: Publication Date from
Vocal Tremor - (vocal OR "vocal cords"[mh]) AND tremor AND (epidemiology OR incidence OR prevalence) Limits: Publication Date from 1997, English; ((vocal OR "vocal cords"[mh]) AND tremor) Limits: Publication Date from 1992, English, Review
Vocal Cord Paralysis - "vocal cord paralysis"[MESH] AND (epidemiology[mh] OR incidence[mh] OR prevalence[mh] OR "occupational exposure"[mh] OR "environmental exposure"[mh]) Limits: Publication Date from 1997, English
Williams Syndrome - "williams syndrome"[MESH] AND (epidemiology[mh] OR incidence[mh] OR prevalence[mh]) Limits: Publication Date from 1997, English; "williams syndrome"[MESH] AND (epidemiology[mh] OR incidence[mh] OR prevalence[mh]) Limits: Publication Date from 1992, English, Review
