Abstract: PD70-10
Sources of Funding: Swiss National Foundation

Introduction

Recent fMRI studies using bladder filling tasks demonstrated alterations in supraspinal LUT control networks (NT) in women with OAB, particularly regarding NT connectivity and white matter changes. It is unclear if patients with OAB show altered supraspinal responses during empty bladder conditions and if resting-state (RS) activity is altered by catheterization usually require for bladder filling tasks._x000D_ We applied a functionally-motivated NT approach, using RS functional NT connectivity (RS-FNC) analysis, to examine RS related NT interactions in age-matched controls and OAB patients. Based on previous publications we hypothesize lower FNC in OAB patients.

Methods

We examined 10 healthy females (37±9y) and 10 with OAB (38±8y) and DO in urodynamics. For RS-fMRI whole brain images, using a multi-slice EPI sequence were acquired in a 3T scanner. Using SPM8, we estimated the RS NTs using the GIFT toolbox and independent component analysis (ICA) across all subjects. IC dimension estimation was performed using the minimum description length criteria, modified to account for spatial correlation. All non-neuronal ICs (e.g. cardiac-induced pulsatile artifact and head motion) were removed, resulting in a total of 9 neuronal ICs (including the default mode NT, DMN). Prior to FNC analysis, IC time courses were bandpass (0.013 Hz & 0.24 Hz). Group differences in FNC strength were calculated using the FNC toolbox for both conditions. The temporal lags between ICA-derived NTs were computed to gain directed FNC. Significant between-group FNC (and lag) results are shown at p < 0.05 FDR corrected.

Results

Healthy controls showed significantly higher (directed) FNC than OAB patients for: DMN (left-dominant) &[rarr] DMN (right-dominant) and fronto-parietal attention NT &[rarr] DMN (left-dominant). OAB patients show lower inter-networkcoupling, especially between the DMN(IC1) and the left-dominant fronto-parietal attention NT (FPN,IC4)._x000D_ Further, FNC differed between groups in temporal synchronicity. E.g., lag time between the DMN and FPN is shorter than between the right and left DMN in OAB patients.

Conclusions

We conclude that the interplay between neuronal NTs is altered in OAB patients compared to healthy subjects already during RS. Aberrant coupling of the fronto-parietal attention NT might indicate a general neuronal deficit that impairs adequate LUT control, i.e. suppression of premature micturition reflex, consequently resulting in OAB and incontinence. These novel findings can be an important link to the underlying pathophysiology of OAB in otherwise neurological unimpaired patients.

Funding

Swiss National Foundation