Journal of Speech Pathology & Therapy
Open Access

Progressive apraxia of speech; Spatial distributions; Heightened magnetic susceptibility; Neuroimaging insights; Speech motor control

Introduction

Progressive apraxia of speech (PAOS) is a neurodegenerative disorder characterized by the deterioration of speech motor planning and execution abilities over time. While the clinical manifestations of PAOS are well-documented, the underlying neural mechanisms remain poorly understood [1,2]. Recent advancements in neuroimaging techniques, particularly magnetic resonance imaging (MRI), have provided valuable insights into the structural and functional alterations associated with PAOS. Among these, spatial distributions of heightened magnetic susceptibility (SDHMS) have emerged as a promising avenue for unraveling the neuropathological underpinnings of PAOS [3,4]. In this article, we explore the spatial distributions of heightened magnetic susceptibility in PAOS, aiming to elucidate their significance in understanding the neuroanatomical correlates of this debilitating disorder [5]. Progressive apraxia of speech (PAOS) is a neurodegenerative disorder characterized by the gradual loss of speech motor control, leading to significant impairments in speech production and articulation. While the clinical manifestations of PAOS are well-documented, the underlying neural mechanisms remain poorly understood [6,7]. Recent advancements in neuroimaging techniques, particularly magnetic resonance imaging (MRI), have provided valuable insights into the structural and functional alterations associated with PAOS. Among these, spatial distributions of heightened magnetic susceptibility (SDHMS) have emerged as a promising avenue for unraveling the neuropathological underpinnings of PAOS. Understanding the spatial distributions of heightened magnetic susceptibility in PAOS can provide crucial insights into the neuroanatomical correlates of this disorder [8]. SDHMS patterns, visualized through susceptibility-weighted imaging (SWI) or quantitative susceptibility mapping (QSM), reflect alterations in brain tissue magnetic properties, such as changes in iron concentration, myelin content, and tissue microstructure. These alterations are indicative of underlying neurodegenerative processes and may be associated with specific speech motor deficits observed in PAOS. we aim to explore the significance of SDHMS in PAOS and its implications for understanding the pathophysiology of this disorder [9]. We will review recent neuroimaging studies that have investigated SDHMS patterns in individuals with PAOS, highlighting key findings and insights into the neuroanatomical substrates of speech motor impairments. Additionally, we will discuss the potential clinical relevance of SDHMS as a biomarker for PAOS diagnosis, prognosis, and treatment monitoring. By unraveling the neuroimaging insights provided by SDHMS in PAOS, we hope to contribute to a better understanding of the neural mechanisms underlying speech motor control and its dysfunction in neurodegenerative disorders [10]. This knowledge may ultimately lead to improved diagnostic accuracy, prognostic markers, and targeted interventions for individuals affected by PAOS, thereby enhancing their quality of life and functional outcomes.

Understanding progressive apraxia of speech

PAOS is a subtype of primary progressive apraxia characterized by the progressive loss of speech motor control, articulatory precision, and phonemic accuracy, with relative sparing of language and cognitive functions. Individuals with PAOS often exhibit speech sound distortions, inconsistent articulatory errors, and difficulty coordinating the movements necessary for speech production. As the disorder progresses, speech intelligibility declines, leading to significant communication impairments and functional limitations.

Neuroimaging insights into PAOS

Neuroimaging studies have provided valuable insights into the neural correlates of PAOS, revealing structural and functional alterations in key brain regions involved in speech motor planning and execution. MRI-based techniques, such as voxel-based morphometry (VBM), diffusion tensor imaging (DTI), and functional MRI (fMRI), have been instrumental in identifying structural abnormalities, white matter alterations, and functional connectivity changes associated with PAOS.

Spatial distributions of heightened magnetic susceptibility

Spatial distributions of heightened magnetic susceptibility (SDHMS) represent alterations in the magnetic properties of brain tissue, reflecting changes in iron concentration, myelin content, and tissue microstructure. These alterations can be visualized using susceptibility-weighted imaging (SWI) or quantitative susceptibility mapping (QSM), allowing for the mapping of brain regions with abnormal magnetic susceptibility. Recent neuroimaging studies have revealed SDHMS patterns in PAOS that are distinct from those observed in other neurodegenerative disorders, such as apraxia of speech in the context of primary progressive aphasia (PPAOS). SDHMS in PAOS are often localized to specific brain regions implicated in speech motor control, including the supplementary motor area (SMA), precentral gyrus, insula, basal ganglia, and cerebellum. These findings suggest that PAOS may involve selective neurodegeneration of speech motor networks, leading to disruptions in motor planning and execution processes.

Significance and implications

Understanding the spatial distributions of heightened magnetic susceptibility in PAOS has significant implications for both clinical diagnosis and therapeutic intervention. By elucidating the neuroanatomical substrates of PAOS, SDHMS patterns may aid in the differential diagnosis of PAOS from other speech and language disorders and help monitor disease progression over time. Furthermore, targeted interventions aimed at preserving or compensating for the integrity of affected brain regions may hold promise for mitigating the communication impairments associated with PAOS.

Conclusion

Spatial distributions of heightened magnetic susceptibility provide valuable neuroimaging insights into the pathophysiology of progressive apraxia of speech. By mapping alterations in brain tissue magnetic properties, SDHMS patterns offer a unique window into the neuroanatomical correlates of PAOS, shedding light on the underlying mechanisms driving speech motor deficits in this disorder. Continued research efforts aimed at further elucidating the significance of SDHMS in PAOS may ultimately lead to improved diagnostic accuracy, prognostic markers, and therapeutic targets for individuals affected by this debilitating condition.

1. Tichenor SE, Yaruss JS (2019)Group experiences and individual differences in stuttering.J Speech Lang Hear Res 62: 4335-4350.

Indexed at, Google Scholar, Crossref

2. Jackson ES, Yaruss JS, Quesal RW, Terranova V (2015)Responses of adults who stutter to the anticipation of stuttering.J Fluency Disord 45: 38-51.

Indexed at, Google Scholar, Crossref

3. Crichton I (2002)Communicating in the real world: Accounts from people who stammer.J Fluency Disord 27: 333-352.

Indexed at, Google Scholar, Crossref

4. Petrunik M, Shearing CD (1983)Fragile facades: Stuttering and the strategic manipulation of awareness.Social Prob31: 125-138.

Indexed at, Google Scholar, Crossref

5. Craig A, Blumgart E, Tran Y (2009)The impact of stuttering on the quality of life in adults who stutter.J Fluency Disord34: 61-71.

Indexed at, Google Scholar, Crossref

6. Arndt J, Healey EC (2001)Concomitant disorders in school-age children who stutter.Lang Speech Hear Serv Sch 32: 68-78.

Indexed at, Google Scholar, Crossref

7. Blood GW, Ridenour VJ, Qualls CD, Hammer CS (2003)Co-occurring disorders in children who stutter.J Commun Disord 36: 427-448.

Indexed at, Google Scholar, Crossref

8. Ntourou K, Conture EG, Lipsey MW (2011)Language abilities of children who stutter: A meta-analytical review.Am J Speech Lang Pathol20: 163-179.

Indexed at, Google Scholar, Crossref

9. Blood GW, Blood I, Kreiger J, Qualls CD (2009)Double jeopardy for children who stutter: race and coexisting disorders.Commun Disord Quart30: 131-141.

Indexed at, Google Scholar, Crossref

10. Boulet SL, Boyle CA, Schieve LA (2009)Health care use and health and functional impact of developmental disabilities among US children.Arch Pediatr Adolesc Med 163: 19-26.

Indexed at, Google Scholar, Crossref