Dear Editor,

Response:

We appreciate Dr. Gudrunardottir and colleagues’ interests and comments to our recent review.

We gave 5.7–8.5 % incidence rate for cerebellar mutism (CM). In previously and recently published series, 1.5–13% incidence rate is given [1–4]. Although Catsman-Berrevoets et al. [1] gave 29% incidence rate for postoperative CM, they did not give any information about the asymptomatic time interval following posterior fossa surgery. Besides the authors did not outline whether postoperative dysarthria and other neurological deficits occurred immediately following posterior fossa surgery or following surgery an asymptomatic brief interval took place. They also stated that they found the highest incidence of postoperative CM. For our opinion, higher incidence rate for CM in previous series could also be attributed to intraoperative trauma related parenchymal edema, ischemia, and tissue damage. In our opinion, the incidence rates given in our review could be a little lower than the reported series but not close to 29%. As we mentioned in our paper, although CM is usually described following cerebellar tumor removal, this syndrome could be seen following any posterior fossa surgery. In a recent article of Dubey et al. [2], they reported 1.5% incidence of CM among all posterior fossa operations and 8% in all cerebellar tumor operations.

In our review, we proposed that complete remission from the CM may frequently seen within the 3 months. We did not mean all the CM cases. Recovery period may even exceed to a year.

We only mentioned and discussed the presumed and proposed risk factors and we did not point out any definitive risk factor for the development of postoperative CM. Besides the risk factors, as mentioned in the letter of Dr. Gudrunardottir et al., are still not considered definitive risk factors for development of postoperative CM.