Page 37 - Bladder Dysfunction in the Context of the Bladder-Brain Connection - Ilse Groenendijk.pdf

A systematic review and meta-analysis of the central innervation of the lower urinary tract 35
Micturition
Eight studies investigated brain areas involved in micturition, of which 5 used fMRI and 3 used PET. The study of Kuhtz-Buschbeck et al. 2009, investigated initiation of voiding only, i.e. participants prevented voiding by contracting the pelvic floor when micturition was about to start, all other studies investigated real micturition. Only in the study of Khavari et al. data of patients with successful micturition (n=7) and unsuccessful mic- turition (n=9) were not reported separately. In four studies, patients could sign (hand or vocally) when they were about to start micturition.15-18 Two studies used a flow/urine detector to detect the start of micturition 5,6 and in two studies patients were instructed when to start micturition.2,4 Six studies found activation in the periaqueductal gray (PAG) and 5 in the pontine micturition center (PMC). Cingulate gyrus was active in 6 studies. The insula, the thalamus, the mid frontal gyrus and the cerebellum were activated in 4 studies. The inferior frontal gyrus (Brodmann area 11, 44 – 47) was found active in all studies. S3 Table shows peak coordinates of brain areas that were reported to be active in at least 3 of the included studies. If, in a single study, more than one cluster was found in the same brain area, the cluster with the highest T- or Z-value is displayed in S3 Table. All other active clusters described in individual studies only, are summarized in S4 Table.
Primary outcome: Activation Likelihood Estimation
Pelvic floor muscle contraction
The ALE analysis of 113 peak coordinates derived from 11 different studies with a total number of 170 subjects of which 71 men and 87 women (all cluster/peak coordinates summarized in S1 and S2 Tables) yielded 10 active clusters using a statistical threshold of p = 0.001 uncorrected with a minimal cluster size of 100 mm3 (Table 4). Fig 2 displays several of the ALE clusters: primary motor cortex, SMA, cingulate gyrus, insula, thalamus, substantia nigra/red nucleus and the cerebellum.
Micturition
The ALE analyses of 98 peak coordinates derived from 8 different studies with a total number of 107 subjects of which 48 men and 59 women (all peak coordinates summa- rized in S3 and S4 Tables) yielded 7 active clusters using a statistical threshold of p = 0.001 uncorrected with a minimal cluster size of 100 mm3 (Table 4). Fig 3 displays exemplarily several of the ALE clusters: PMC, PAG, thalamus, cingulate gyrus, frontal gyrus and insula. Cluster 1 shows peak activations in the thalamus, PMC and PAG, but is also situated in the cerebellum.
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