Nonverbal autism, also called nonspeaking autism, is a subset of autism spectrum disorder (ASD) where the person either does not learn how to speak, or has a delay or difficulty with speech.
Background Researchers use several terms, including nonspeaking, minimally verbal, and minimally speaking to describe autistic people who use little or no spoken language. There is no universally accepted definition of nonverbal autism, and studies have used different criteria, ranging from the absence of functional speech to the use of fewer than 20 or 30 functional words. This variation has contributed to difficulties in comparing prevalence estimates and research findings across studies. Research has examined the relationship between early language development and later developmental outcomes in autistic children. The acquisition of functional spoken language during early childhood is generally associated with more favorable developmental outcomes, although spoken language may also emerge later. A review identified 167 autistic individuals who reportedly acquired speech at age five or older, with most cases occurring between ages five and seven. Estimates of the proportion of autistic children who remain minimally verbal vary depending on the definitions and assessment methods used. Reviews have commonly estimated that approximately 25% to 30% of autistic children develop little or no functional spoken language, while individual studies have reported estimates ranging from approximately 25% to 35%. The biological basis of autism is not fully understood. Characteristics associated with autism, including differences in social communication, language development, and restricted or repetitive behaviors and interests, often become apparent between the ages of two and three. Many autistic children are diagnosed during early childhood as a result. Various co-occurring conditions, including epilepsy, attention deficit hyperactivity disorder, gastrointestinal problems, sleep disorders, hypermobility, depression, and anxiety, are also reported among autistic people.
Early predictors The factors associated with nonspeaking autism are not fully understood. Research has identified associations between joint attention abilities and verbal communication in autistic children. Joint attention refers to the shared focus of two individuals on an object or event, often achieved through behaviors such as pointing, eye gaze, or gestures. The development of joint attention during early childhood is associated with later language skills, and studies have reported differences in joint attention behaviors among autistic children compared with non-autistic children. Research indicates that autistic children may experience differences in both initiating and responding to joint attention. Some studies have found that responding to joint attention may change with development, while individual differences in joint attention abilities have been associated with cognitive and developmental factors. A systematic review and meta-regression found an association between joint attention abilities and language skills in both autistic and typically developing participants, although the strength of this association varied depending on the type of joint attention measured and across different studies. Other research has suggested that early joint attention abilities may be associated with later gains in expressive language among autistic individuals. Some studies have also examined the relationship between sensory processing patterns and communication development in nonspeaking autistic children. One study suggested that patterns such as reduced responsiveness to some stimuli (hyporesponsiveness) and increased interest in certain sensory experiences (sensory seeking) may be more common among nonspeaking autistic children and may be associated with differences in communication development. Research has also identified differences in nonverbal communication during early childhood. In comparisons of autistic children aged two to three years with children who had other developmental delays and typically developing children, autistic children showed greater differences in measures such as joint attention, eye contact, pointing, and gesture use. These differences in early nonverbal communication have been studied as potential characteristics that may help differentiate autism from other developmental conditions.
Assessment Assessing language, cognition, and communication in minimally verbal autistic people can be difficult, because many standardized assessments require spoken instructions or spoken responses. Recommended assessment practices include using multiple measures, allowing additional time, reducing unnecessary verbal demands, and accepting alternative response methods. Eye tracking and neurophysiological measures have also been investigated because they can assess some abilities without requiring an overt spoken or motor response.
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