title: Functional connectivity changes in adults with developmental stuttering: a preliminary study using quantitative electro-encephalography.
abstract: BACKGROUND
  Stuttering is defined as speech characterized by verbal dysfluencies, but should not be seen as an isolated speech disorder, but as a generalized sensorimotor timing deficit due to impaired communication between speech related brain areas. Therefore we focused on resting state brain activity and functional connectivity.
  
  
  METHODS
  We included 11 patients with developmental stuttering and 11 age matched controls. To objectify stuttering severity and the impact on quality of life (QoL), we used the Dutch validated Test for Stuttering Severity-Readers (TSS-R) and the Overall Assessment of the Speaker's Experience of Stuttering (OASES), respectively. Furthermore, we used standardized low resolution brain electromagnetic tomography (sLORETA) analyses to look at resting state activity and functional connectivity differences and their correlations with the TSS-R and OASES.
  
  
  RESULTS
  No significant results could be obtained when looking at neural activity, however significant alterations in resting state functional connectivity could be demonstrated between persons who stutter (PWS) and fluently speaking controls, predominantly interhemispheric, i.e., a decreased functional connectivity for high frequency oscillations (beta and gamma) between motor speech areas (BA44 and 45) and the contralateral premotor (BA6) and motor (BA4) areas. Moreover, a positive correlation was found between functional connectivity at low frequency oscillations (theta and alpha) and stuttering severity, while a mixed increased and decreased functional connectivity at low and high frequency oscillations correlated with QoL.
  
  
  CONCLUSIONS
  PWS are characterized by decreased high frequency interhemispheric functional connectivity between motor speech, premotor and motor areas in the resting state, while higher functional connectivity in the low frequency bands indicates more severe speech disturbances, suggesting that increased interhemispheric and right sided functional connectivity is maladaptive.
authors.affiliation: Department of Neurosurgery, University Hospital Antwerp Antwerp, Belgium ; Department of Translational Neuroscience, Faculty of Medicine, University of Antwerp Antwerp, Belgium.
authors.forename: Kathleen
authors.initials: K
authors.lastname: Joos
authors.affiliation: Department of Surgical Sciences, Dunedin School of Medicine, University of Otago Dunedin, New Zealand ; BRAI2N and TRI, Sint Augustinus Hospital Antwerp, Belgium.
authors.forename: Dirk
authors.initials: D
authors.lastname: De Ridder
authors.affiliation: Centre of Stuttering Therapy Antwerp, University of Antwerp Antwerp, Belgium ; Faculty of Medicine and Health Sciences, University of Antwerp Antwerp, Belgium.
authors.forename: Ronny A
authors.initials: RA
authors.lastname: Boey
authors.affiliation: Department of Translational Neuroscience, Faculty of Medicine, University of Antwerp Antwerp, Belgium ; School of Behavioral and Brain Sciences, The University of Texas at Dallas Richardson, TX, USA.
authors.forename: Sven
authors.initials: S
authors.lastname: Vanneste
keywords: developmental stuttering; functional connectivity; qEEG; sLORETA; sensorimotor timing deficit