Anorectal manometric anomalies in seven patients with frontal lobe brain damage

We studied the anorectal manometric and urodynamic pattern of seven patients who had right and/or left frontal lobe injury to investigate the possibility that the frontal lobe area plays an important role in control of anorectal motility as it does for the urinary bladder. We found that the disturbances of anorectal manometric recordings were similar to those of urodynamic recordings: (1) lack of urinary bladder filling sensation (two cases), increased perception threshold of rectal distension (two cases); (2) uninhibited detrusor contractions during filling (five cases), spontaneous rectal contractions during the resting step (four cases); (3) absence of micturition (one case), absence of rectoanal inhibitory reflex (one case). Furthermore, in all but one patient, we observed a decrease in the amplitude and duration of the voluntary contraction of the anal canal (six cases). However, in two of the seven patients we found hypertonia in the anal canal (upper part: one case, lower part: one case), but never in the urethral canal. Our results suggest that frontal lobe may be involved in the nervous control of anorectal motility as it is for urinary bladder function. However, the lack of correlation between urinary and anorectal anomalies in individual cases suggests that these functions depend on distinct areas of the frontal lobe.