Speech is a communication skill that enables people to understand each other during interactions. It refers to verbally expressing thoughts and ideas through a shared language. Language is an agreed-upon rule-based code that people use to communicate. Speech is a means of communication that allows people to share beliefs, ideas, and opinions. Communication becomes problematic when the speech process gets disrupted, or the normal flow of the receptive and expressive components of speech gets compromised. Disturbances of speech can come in various ways, such as challenges with content formation, in that an individual has challenges in expressing the desired ideas in spoken words, and challenges of articulation, in that one can express their ideas in spoken form, but with physical challenges in producing the words or sounds necessary for intelligible speech (Naqvi & Winters, 2022). This research edges toward the challenges of articulation, mainly focusing on stuttering.
Stuttering is a speech flow interruption characterized by various disfluency types, such as the repetition of syllables, sounds, and monosyllabic words. Consonant prolongations and blockages can also characterize stuttering. The disfluencies in stuttering can affect the rhythm and rate of speech (Junuzovic-Zunic et al., 2021). It is essential to examine stuttering since Naqvi and Winters (2022) assert that challenges of articulation during speech can result in communication challenges. It is also essential to study the stuttering issue since Junuzovic-Zunic et al. (2021) assert that it is often accompanied by adverse reactions to speaking, struggling behaviors, avoidance behaviors, and physical tension.
Here, a literature review examines stuttering across the various lifespan stages, from infancy to adulthood. The impacts of stuttering in each stage of the lifespan are explored, including how stuttering in the various stages of the lifespan influences stuttering in later lifespan stages. The study argues that stuttering at an earlier stage in the lifespan decreases the probability of stuttering in the later life stages.
Stuttering in Early Childhood
Early childhood is a critical period in child development that starts before birth and proceeds around age 8. This period is critical since it is at this time that children experience rapid brain and body development. In these first few years of life, more than a million new neural connections get formed, and the experiences and opportunities offered in early childhood lay the foundation for a child’s growth, learning, relationship-building, and school preparation (The American Academy of Pediatrics, n.d.). Therefore, early childhood is a crucial time to consider when evaluating speech challenges such as stuttering.
Diagnosis and Onset of Stuttering
In DSM IV (Diagnostic and Statistical Manual, fourth edition), stuttering was listed as an Axis 1 disorder. However, in DSM V, initially published in 2013, the American Psychiatric Association (APA) modified the classification and description of stuttering. The body changed the diagnostic label from stuttering to childhood-onset fluency disorder, removing the limited criteria that did not allow for the distinguishing of adult-onset stuttering from childhood-onset fluency disorder and the inclusion of anxiety/avoidance criteria concerning speaking situations (Maguire et al., 2020). Therefore, it is crucial to note that stuttering in early childhood is commonly referred to as childhood-onset fluency disorder.
A childhood-onset fluency disorder is characterized by dysfluency. Maguire et al. (2020) explain that stuttering meets the criteria as a disorder when it causes functional impairments. DSM V and APA define childhood-onset fluency disorder as a disturbance in the typical time pattern and fluency of speech inappropriate for a child’s age that is persistent over time. The symptoms of childhood-onset fluency disorder include prolongations, repetitions, broken words, blocking, circumlocutions, and excessive physical tension (Maguire et al., 2020). Maguire et al. (2020) further say that motor movements such as head jerking, tics, eye blinks, and breathing movements can also accompany stuttering. The extent of the symptoms varies situationally and is exacerbated with fearful anticipation of stuttering.
Dysfluency due to childhood-onset fluency disorder starts gradually, affecting simple words. However, the dysfluency becomes more frequent and interferes with complete phrases as the disorder progresses. The age of developmental stuttering onset ranges from 2-7 years, with 80-90% of the affected children showing symptoms by age 6 (Maguire et al., 2020). Maguire et al. (2020) assert that chronic speech-motor disorder affects about 5% of children. However, recent data has suggested an increase in the lifetime incidence toward 10%, with most incidents occurring in children.
Causes and Risk Factors
Stuttering has been present in all cultures throughout recorded history. However, to date, the exact cause is still unknown. Maguire et al. (2020) explain that stuttering is presently viewed as a neurologic disorder brought on by incomplete dominance of the brain’s primary speech centers with a multifaceted etiology. This is a different perspective from the traditional approaches that viewed stuttering as a brain abnormality, increasing stigma toward stuttering.
Genetics is a risk factor for childhood-onset fluency disorder. Maguire et al. (2020) explain that genetics are involved in several stuttering cases, with twin and family studies suggesting that genetics account for 50-80% of stuttering. Twin studies have indicated that monozygotic twins display higher concordance for stuttering than dizygotic ones. Furthermore, estimated heritability has been shown to exceed 0.80 in some studies. Also, Maguire et al. (2020) assert that there is a three times higher risk of stuttering in children with first-degree biological relatives who stutter compared to the general population.
Anxiety is another risk factor for exacerbating the symptoms of stuttering. Maguire et al. (2020) explain that stuttering is made worse with anxiety, is associated with tic motions, and has symptoms worsened by dopamine agonists. This is much like Tourette’s Syndrome. Both stuttering and Tourette’s Syndrome are improved with dopamine antagonists. Furthermore, Maguire et al. (2020) report that some cases of stuttering can result from pediatric autoimmune disorders associated with streptococcus infections (PANDAS). Some studies have hypothesized that stuttering occurs when antibodies attach to the developing basal ganglia instead of the intended streptococcal infection.
Impact of Childhood-Onset Fluency Disorder
Childhood-onset fluency disorder has impacts that cannot be understated. For instance, according to Maguire et al. (2020), the disorder often leads to embarrassment, anxiety, insecurity, stress, bullying, and shame in early childhood. These effects lead to limitations in social participation and academic achievements. Sander and Osborne (2019) outline other effects of childhood-onset fluency disorder, such as negative self-perception, negative perception by others, anxiety, and sometimes depression. Early recognition of the disorder is vital in ensuring that compensatory changes to the brain can still occur and minimizing the chances of developing social anxiety, impaired social skills, negative attitudes toward communication, and maladaptive compensatory behaviors.
Impact on Future Lifespan Stages
While dysfluency increases during early childhood, this effect has been proven to wane in future lifespan stages. For instance, according to Maguire et al. (2020), 65-85% of children with childhood-onset fluency disorder recover from dysfluency by age 16, leading to a prevalence of less than 1% of dysfluency in adults. Similar remarks are made in other sources. According to Stamurai (2020), if a child has stuttered since they were a toddler, the highest probability is that the stuttering will not worsen with age, referring to future stages in the lifespan. However, circumstances that cause emotional strain or induce anxiety can make stuttering worse. Stamurai (2020) says that parents should watch out for such circumstances in the next life stage of adolescence and teenage since adolescents are prone to challenges at school and in their social lives. These challenges can cause increased stuttering during the teen stages despite the expected reduction in dysfluency from stuttering.
Stuttering In Teens
Stuttering often begins in early childhood during the preschool years. As described previously, the early onset of stuttering should not increase when a child transitions to their teenage years. Maguire et al. (2020) assert that 65-85% of children with childhood-onset fluency disorder recover from dysfluency by age 16, leading to a prevalence of less than 1% of dysfluency in adults. Also, Stamurai (2020) explains that if a child has stuttered since they were a toddler, the highest probability is that the stuttering will not worsen with age, and the child is expected to recover in their teenage years. While it can be alarming when a child struggles with speaking, most people know that the phenomenon is relatively common among young children, and the next steps are usually easy to figure out. However, this is not always the case when children develop speech problems in their teens. Gore (2021) explains that sometimes, stuttering starts in adolescence and even in the late teen years due to various factors, which will be discussed below.
Causes and Risk Factors
Various factors can cause the onset of stuttering during the teenage years. One such factor is neurogenic factors, referring to the result of a brain injury (Gore, 2021; Junuzovic-Zunic et al., 2021). According to Junuzovic-Zunic et al. (2021), neurogenic stuttering is a subtype of acquired stuttering characterized by disfluencies associated with acquired brain damage. The pathophysiological mechanism is not yet understood fully. However, neurogenic stuttering is thought to be associated with different lesion sites. Some studies exploring the etiology of neurogenic stuttering have proven that it cannot be exclusively associated with damage to specific parts of the brain but can entail various neurologic structures that are part of the neural network for fluent speech production. The neurologic structures involved include the four lobes of both hemispheres: subcortical white matter, cerebellum, basal ganglia, brainstem, and thalamus. The brain’s left hemisphere is most affected (Junuzovic-Zunic et al., 2021). According to Junuzovic-Zunic et al. (2021), in most cases, neurogenic stuttering results from stroke. An occurrence of neurogenic stuttering from stroke is not limited to specific brain-region lesions. However, it is a result of overlap with the cortico-basal ganglion-cortical network that includes the upper temporal cortex, the lower frontal cortex, basal ganglia, the intraparietal cortex, and their white matter interconnections through the superior internal capsule and longitudinal fasciculus.
Another cause of stuttering onset during teenage years is drug use. Nikvarz and Sabouri (2022) describe drug-induced stuttering (DIS) as neurogenic. While DIS is not significantly reported in studies, Nikvarz and Sabouri (2022) examined drug use as a risk factor for developing stuttering. Nikvarz and Sabouri (2022) found that most DIS cases were related to antipsychotic drugs. Most people with DIS were male, and repetitions followed by speech blocks primarily characterized DIS. In 55.8% of the DIS cases, drug withdrawal was the therapeutic measure used to manage the stuttering. Nikvarz and Sabouri (2022) also reveal that focusing on the cortico-BG-thalamocortical loop, white matter fiber tracts, and their transmitters, such as glutamate and dopamine, reveal some likely mechanisms for DIS. Nikvarz and Sabouri (2022) provide precise descriptions of DIS. For instance, Sertraline is described to have a relation to the serotonergic inhibition of the dopaminergic neurons. The cell bodies of the neurons are located in the ventral tegmental area. Therefore, inhibiting the dopamine pathways in the nigrostriatum can be considered a mechanism of stuttering promotion by sertraline and other selective serotonin reuptake inhibitor (SSRI) drugs in general.
A child can start stuttering in their teens due to non-neurogenic reasons. Gore (2021) asserts that the cause of stuttering in the teenage period is not always neurogenic (from brain injury) or psychogenic (from trauma). Sometimes, the causes of childhood-onset fluency disorder may occur later in life, leading to teen-onset stuttering. For instance, a child can develop stuttering as a teenager because of genetics. Maguire et al. (2020) explain that genetics are involved in several stuttering cases, with twin and family studies suggesting that genetics account for 50-80% of stuttering. Twin studies have indicated that monozygotic twins display higher concordance for stuttering than dizygotic ones. Furthermore, estimated heritability has been shown to exceed 0.80 in some studies. Also, Maguire et al. (2020) assert that there is a three times higher risk of stuttering in children with first-degree biological relatives who stutter compared to the general population. In this case, anxiety is also a risk factor for teenage-onset stuttering.
Diagnosis
It is important to note that the diagnosis criteria of late-onset stuttering are the same as that of stuttering onset in early childhood. Therefore, stuttering in teenagers is also characterized by dysfluency. Maguire et al. (2020) explain that stuttering meets the criteria as a disorder when it causes functional impairments. DSM V and APA define childhood-onset fluency disorder as a disturbance in the regular time pattern and fluency of speech inappropriate for a child’s age that is persistent over time. The symptoms of childhood-onset fluency disorder include prolongations, repetitions, broken words, blocking, circumlocutions, and excessive physical tension (Maguire et al., 2020). Maguire et al. (2020) further say that motor movements such as head jerking, tics, eye blinks, and breathing movements can also accompany stuttering. The extent of the symptoms varies situationally and is exacerbated with fearful anticipation of stuttering.
Impact on Future Lifespan Stages
The impact of adolescent stuttering on later life stages is not vastly documented. However, some sources, such as Stamurai (2020), assert that if a child starts stuttering as a toddler, their stuttering is unlikely to worsen with age. However, as a teenager, a child is likely to face many challenges at school and in their social life that can contribute to increased frequency and severity of the previous stutter. Stamurai (2020) explains that if a parent notices their teenage child’s stutter getting worse with each passing day, they should speak to a speech therapist and a psychologist. Furthermore, according to Maguire et al. (2020), 65-85% of children with childhood-onset fluency disorder recover from dysfluency by age 16, leading to a prevalence of less than 1% of dysfluency in adults. This indicates that stuttering in adolescence does not get worse into adulthood and is expected to recover even before an individual gets to the early adulthood stage.
Stuttering In Adulthood
As described in the previous sections, most stuttering cases start in early childhood. According to Costa et al. (2022), about 70-80% of the children diagnosed with stuttering recover naturally from the disorder during their teens, especially by around the time they are 16 years old. This means there is a more negligible prevalence of stuttering in adulthood than in childhood. According to Trauner and Nass (2017), the prevalence of stuttering as a lifetime disorder is very low, ranging from 0.5% to 1%. The prevalence is lower than the incidence, which is at 4%-5%. Trauner and Nass (2017) assert that persistent stuttering can be associated with other language impairment aspects, such as difficulties processing syntactic information. Maguire et al. (2020) report similar statistics, such as 65-85% of children with childhood-onset fluency disorder recovering from dysfluency by age 16, leading to a prevalence of less than 1% of dysfluency in adults.
Characteristics and Risk Factors of Persistent Stuttering
Stuttering into adulthood is commonly referred to as persistent stuttering. Singer et al. (2020) explored the characteristics associated with persistent stuttering. The study found that individuals with persistent stuttering were likely older when the stuttering started. Furthermore, individuals with persistent stuttering were associated with higher frequencies of stuttering-like disfluencies, lower speech sound accuracy, and lower receptive and expressive language skills than those who recovered as children. Males and children with a family history of stuttering were also highly prone to persistent stuttering (Singer et al., 2020). Costa et al. (2022) also explored the risk factors of persistent stuttering, highlighting that identifying children likely to develop it is vital since they are at an increased risk of developing social, emotional, and academic difficulties. Costa et al. (2022) found that the risk factors for developing persistent stuttering include significantly increased efforts to speak, negative family attitudes toward a child’s speech, and complaints of severe stuttering for more than twelve months. Therefore, Costa et al. (2022) recommend that upon observing some signs of persistent stuttering, they should refer to a formal speech assessment by a pathologist.
Causes of Stuttering for Adults
Stuttering is less common for adults than children. According to Cleveland Clinic (2022), when adults begin to stutter, they need to get tested since it is likely a sign of aphasia. Aphasia refers to a disorder that affects communication. Some conditions that can cause aphasia include traumatic brain injuries, tumors, and strokes. This means that stuttering that begins in adulthood is less likely to result from early childhood causes such as genetics. Adult onset of stuttering is most likely an acquired type of stuttering. Cleveland Clinic (2022) explains that some of the tests that can be conducted on an adult individual experiencing acquired stuttering include computer tomography (CT) scans, magnetic resonance imaging (MRI) scans, and positron emission tomography (PET) scans.
Impact of Stuttering on Adulthood
Adults who stutter say that stuttering signifies a constellation of experiences beyond what others can observe, such as disfluency. They report that the moment of stuttering often begins with anticipation sensations, feeling stuck, and losing control. The sensation can cause speakers to react in various ways, including behavioral, affective, and cognitive reactions that can become deeply ingrained as people struggle to say what they want. These reactions can be associated with adverse impacts on people’s lives. For instance, adults can have substantial psychosocial morbidity characterized by social anxiety and low quality of life (Tichenor & Yaruss, 2019). It is important to note that outside environmental factors can exacerbate the interrelated chain of events that adversely affect adults who stutter. An example of an environmental factor is listeners’ reactions.
Conclusion
Stuttering at an earlier stage in the lifespan decreases the probability of stuttering in the later stages of life. Dysfluency due to childhood-onset fluency disorder starts gradually, affecting simple words. However, the dysfluency becomes more frequent and interferes with complete phrases as the disorder progresses. The age of developmental stuttering onset ranges from 2-7 years, with 80-90% of the affected children showing symptoms by age 6. Chronic speech-motor disorder affects about 5% of children. However, recent data has suggested an increase in the lifetime incidence toward 10%, with most of the incidents occurring in children. Nevertheless, about 70-80% of the children diagnosed with stuttering recover naturally from the disorder during their teens, especially by around the time they are 16 years old. Later onset of stuttering is likely to be acquired, such as neurogenic or drug-induced stuttering. Adult-onset stuttering is less common, and the prevalence among adults is less than 1%. Stuttering has been linked to negative self-perception, negative perception by others, anxiety, and, sometimes, depression. Therefore, individuals with stuttering disorders should be referred to a pathologist, psychologist, or speech therapist for assistance through speech therapy.
References
Cleveland Clinic. (2022, December 14). Stuttering. Retrieved October 9, 2023, from https://my.clevelandclinic.org/health/diseases/14162-stuttering
Costa, J. B., Ritto, A. P., Juste, F., Sassi, F. C., & de Andrade, C. R. F. (2022). Risk factors for the development of persistent stuttering: What every pediatrician should know. International Journal of Environmental Research and Public Health, 19(9), 5225.
Gore, K. (2021, August 16). Why do teens develop a stutter? Speech IRL. Retrieved October 9, 2023, from https://www.speechirl.com/why-do-teens-start-to-stutter
Junuzovic-Zunic, L., Sinanovic, O., & Majic, B. (2021). Neurogenic stuttering: Etiology, symptomatology, and treatment. Medical Archives, 75(6), 456.
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Naqvi, Y., & Winters, R. (2022). Speech Assessment. In StatPearls [Internet]. StatPearls Publishing.
Nikvarz, N., & Sabouri, S. (2022). Drug-induced stuttering: A comprehensive literature review. World Journal of Psychiatry, 12(2), 236.
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Singer, C. M., Hessling, A., Kelly, E. M., Singer, L., & Jones, R. M. (2020). Clinical characteristics associated with stuttering persistence: A meta-analysis. Journal of Speech, Language, and Hearing Research, 63(9), 2995-3018.
Stamurai, T. (2020, September 13). Teenage stuttering: how can parents help. Stamurai Blog. https://stamurai.com/blog/parental-guide-to-teenage-stuttering/#:~:text=If%20your%20child%20has%20been,and%20in%20their%20social%20life.
The American Academy of Pediatrics. (n.d.). Early Childhood. Retrieved October 9, 2023, from https://www.aap.org/en/patient-care/early-childhood/#:~:text=Early%20childhood%20is%20a%20pivotal,rapid%20brain%20and%20body%20development.
Tichenor, S. E., & Yaruss, J. S. (2019). Stuttering is defined by adults who stutter. Journal of Speech, Language, and Hearing Research, 62(12), 4356-4369.
Trauner, D. A., & Nass, R. D. (2017). 53 – Developmental language disorders. Science Direct, pp. 431–436.
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