The cerebellum has gradually been recognized as having an essential role in the complex neural systems for movement, balance, working memory, executive function, visual-spatial function, linguistic processing, attention, emotional modulation, and mood.1 Patients with posterior fossa lesions classically present with ataxia and incoordination. Cognitive, mood, and behavioral problems, however, are being described more often.2,3
A posterior fossa syndrome has been reported in up to 30% of children following resection of cerebellar neoplasms.4,5 These children were first noted to be mute postoperatively, while bizarre behavior, emotional lability, extreme irritability, and decreased initiation of voluntary behavior were described later. These symptoms have been attributed to lesions of the vermis or floor of the fourth ventricle or both.4,5 Large tumors, midline location, and vermal incision increase the risk for posterior fossa syndrome,6 which is expected to resolve within weeks or months.7 In one study of 253 pediatric patients,7 20 (8%) presented with postoperative cerebellar mutism. In another study of 142 children,8 transient mutism, bizarre personality changes, emotional lability, and decreased initiation of speech and voluntary movement were reported in 12 (8%) patients, all of whom had midline resections and lesions of the vermis.
A chronic cerebellar affective syndrome was first described in adults in association with a variety of cerebellar lesions, including cerebellar infarction, cerebellitis, cerebellar cortical atrophy, and midline cerebellar tumors.9 It is characterized by impaired executive function (planning, set-shifting, verbal fluency, abstract reasoning, and working memory), impaired visuospatial cognition and memory, flattening or blunting of affect, disinhibited or inappropriate behavior, and agrammatism and dysprosody of speech.9
Cerebellar cognitive affective syndrome has also been reported in children after resection of posterior fossa tumors.4 Similar to adults, these children had persistent impairment in executive function, planning and sequencing, visual-spatial function, expressive language, verbal memory, and modulation of affect. Extensive vermis damage was associated with irritability, impulsivity, disinhibition, and poor attention.4
This study was undertaken to describe the acute psychiatric changes in mood and behavior in children with posterior fossa lesions and to evaluate the relationship between posterior fossa syndrome and cerebellar cognitive affective syndrome.
Patients with cerebellar lesions and acute changes in behavior and mood were collected from 2,063 inpatient psychiatric consultations conducted at Children’s Hospital in Los Angeles, California from January 1992 through December 2000. Neurologic and psychiatric examinations and neuroimaging studies were conducted on all patients and were retrospectively reviewed. Neuropsychologic assessments were performed later, following the postoperative inpatient period. The same child-adolescent psychiatrist performed all consultations and data collection. Clinical descriptions of behavior, mood, and other symptoms were routinely noted, but the degree of impairment was not quantified. Descriptive statistical analyses were employed.
Nineteen patients with posterior fossa lesions and acute changes in mood and behavior were observed during the 9-year study period. There were 12 girls and seven boys, ranging from 2.8 to 15.7 years old (mean=7.6, median=7.0). Two patients were seen 6 weeks after surgery, but the majority were seen during the immediate postoperative period (range=2 to 18 days, mean=9 days, median=8 days).
There were 17 patients with posterior fossa neoplasms: eight had primitive neuroectodermal tumors; six had astrocytoma; one had choroid plexus carcinoma; and one had dermoid. Two patients had acute hemorrhages in the posterior fossa due to ruptured arteriovenous malformations located in the midline and left cerebellar hemisphere. Patients presented with headache (n=17), nausea and vomiting (n=16), ataxia (n=7), abnormal vision (n=6), irritability (n=5), and lethargy or sleepiness (n=5).
Preoperative neuroimaging studies documented large (3—5 cm diameter) posterior fossa lesions, predominantly in the midline (n=13), right (n=4), or left (n=4) side and occasionally with hydrocephalus (n=7). A midline surgical approach was utilized for all resections, including lateral lesions. Postoperative scans were available for 14 of the 19 patients, and defects were present in all residual midline involving the vermis and fourth ventricle (n=6), vermis alone (n=6), or fourth ventricle alone (n=2).
All 19 patients were markedly dysphoric, distressed, and inattentive, with poor eye contact, at psychiatric consultation. They were irritable (n=17), crying (n=14) and seemed inconsolable (n=11). Some were withdrawn and apathetic (n=9), while others were agitated, yelling (n=7), and having tantrums (n=5). Affect was variable, from labile (n=5) to sad (n=3) or flat (n=6). Ten of the 19 children were transiently mute following surgery. Psychomotor retardation was noted in seven, and one was akinetic. Two children met criteria for delirium, which soon resolved. Ventriculoperitoneal shunt for hydrocephalus was required in 14 of the 19. Carbamazepine was given to nine of the children for mood stabilization, which was effective.
This study describes an acute syndrome of severe dysphoria, inattention, and emotional distress in 19 children with midline posterior fossa lesions. The observation of preoperative irritability in five (26%) children might be an early clinical indication of a cerebellar lesion. In a large, multicenter study of brain tumors, irritability was noted at presentation in 22% of 1,752 children (mean age=6 years) with a posterior fossa tumor.10
It was not possible to determine the prevalence of mood symptoms in pediatric patients with acute cerebellar lesions from this study, as only cases referred to the consultation-liaison service were reviewed. Carbamazepine was found to be beneficial in controlling the severe dysphoria and irritability in nine of the patients in whom it was used.11 The role of mood stabilizing anticonvulsants and other psychotropic medications in these patients merits further investigation.
This study maintains that the severe mood, behavioral, and cognitive symptoms of the posterior fossa syndrome are similar to the changes described in the cerebellar cognitive affective syndrome. Both disorders represent clinical observations of the same pattern of cerebellar dysfunction, occurring either acutely and designated the posterior fossa syndrome, or persistently over time and termed cerebellar cognitive affective syndrome. Posterior fossa syndrome can be considered to represent the acute manifestation of cerebellar cognitive affective syndrome.
This article was presented at the American Academy of Child and Adolescent Psychiatry, Honolulu, October 2001.