The evaluation and comparison of cerebellar mutism in children and adults after posterior fossa surgery: report of two adult cases and review of the literature.

BACKGROUND

Although there are some cases of cerebellar mutism in adults after posterior fossa surgery for cerebellar tumour it generally occurs in children. Reversible pathophsiology and the anatomical substrate of this syndrome still remain unclear. The predominance of cerebellar mutism in children is suggested to be related to the higher incidence of posterior fossa tumours in children. However, the question regarding the reason for the obvious difference in the incidence of this syndrome between the paediatric and adult population still remaining unanswered. The aim of this study was to evaluate and compare children and adult groups separately to understand the incidence and the clinical characteristics better and to elucidate the pathophysiological basis and predictive factors for this syndrome.

METHOD

We reviewed, analysed, and compared the cases of cerebellar mutism individually in children and in adults reported in the English literature. We found 106 reported cases in children and 11 cases in adults which were suitable for analysis. We added two adult cases to these.

FINDINGS

The ages of the patients ranged from 2 to 16 (mean, 6.4 year) in children and from 17 to 74 (mean, 38.7 year) in adults. Although vermis was the main location in both groups, the incidence of vermis lesions was considered higher in the paediatric population (%91.5 versus %69.2). The rate of brain stem invasion was prominent in children (%31.1) when compared with adults (%7.6). The latency for the development of mutism and the duration of the mutism were similar in children and adults (mean, 1.4 d versus 2 d and mean, 5.07 wk versus 4.2 wk respectively). Mutism was transient in all the cases of both groups.

INTERPRETATION

Recent concepts of cerebellar physiology disclose the importance of the cerebellum in learning, language, and mental and social functions. Pontine nuclei, the thalamus, motor and sensory areas and supplementary motor areas have been proven necessary for the initiation of speech. It can be hypothesized that uncompleted maturation of the reciprocal links in childhood connecting the cerebellum to these structure makes the children more vulnerable to have postoperative cerebellar mutism in comparison to the adult population.