Brain developmental trajectories associated with childhood stuttering persistence and recovery

Knowns and unknowns about the neurobiology of stuttering

“…White matter structure differences have also been observed, affecting areas involved in auditory–motor integration, motor initiation, monitoring, and interhemispheric coordination [ 77 – 80 ]. These structural differences are correlated with stuttering severity [ 77 ], suggesting their relevance to speech fluency.…”

“…In contrast to adults, a recent report showed that children who would go on to have persistent stuttering exhibit significantly reduced volume of the putamen early in development [ 77 ]. However, this discrepancy diminishes with age, and an intriguing paradox emerges during adulthood, where adults who stutter exhibit increased neural activity within the basal ganglia, including the putamen [ 86 ] and caudate nucleus [ 41 ].…”

“…The development of fluent speech involves learning to produce long motor sequences [ 65 ], which leads to the specialization of neural circuits that enable the effortless and fluid execution of fast and precise sequential movements [ 94 ]. Neuroimaging data, although scarce, has shown that initially, recovering children share neuroanatomical deficits with children with persistent stuttering, but these tend to normalize over time, with growth rates of white matter microstructure sometimes exceeding those observed in children who do not stutter [ 77 , 79 ]. Spontaneous recovery is primarily linked to age-related growth in white matter structures [ 77 , 79 ] that enable fast and accurate sequential speech movements.…”

“…Neuroimaging data, although scarce, has shown that initially, recovering children share neuroanatomical deficits with children with persistent stuttering, but these tend to normalize over time, with growth rates of white matter microstructure sometimes exceeding those observed in children who do not stutter [ 77 , 79 ]. Spontaneous recovery is primarily linked to age-related growth in white matter structures [ 77 , 79 ] that enable fast and accurate sequential speech movements. These white matter structures, including the corticospinal tract, superior longitudinal fasciculus, arcuate fasciculus, the somatomotor part of the corpus callosum, and cerebellar peduncles [ 77 ] ( Fig 2 , left panel), interconnect gray matter regions that showed significant reductions in volume in children with persistent stuttering, including the left ventral motor cortex and the left dorsal premotor cortex [ 76 ].…”

“…Spontaneous recovery is primarily linked to age-related growth in white matter structures [ 77 , 79 ] that enable fast and accurate sequential speech movements. These white matter structures, including the corticospinal tract, superior longitudinal fasciculus, arcuate fasciculus, the somatomotor part of the corpus callosum, and cerebellar peduncles [ 77 ] ( Fig 2 , left panel), interconnect gray matter regions that showed significant reductions in volume in children with persistent stuttering, including the left ventral motor cortex and the left dorsal premotor cortex [ 76 ]. Recovery might require a better interareal connectivity within the speech network, a level of brain development that children with stuttering persistence do not achieve.…”