Abstrakt

Clinical and methodological confounders in assessing the cerebellar cognitive affective syndrome in adult patients with posterior fossa tumours

Dashne Omar

The Cerebellar Cognitive Affective Syndrome (CCAS) was first described by Schmahmann and Sherman as a constellation of symptoms including dysexecutive syndrome, spatial cognitive deficit, linguistic deficits and behavioural abnormalities in patients with a lesion in the cerebellum with otherwise normal brain. Neurosurgical patients with cerebellar tumours constitute one of the cohorts in which the CCAS has been described. In this paper, we present a critical review of the literature of this syndrome in neurosurgical patients. Thereafter, we present a prospective clinical study of 10 patients who underwent posterior fossa tumour resection and had a detailed postoperative neuropsychological, neuropsychiatric and neuroradiological assessment. Because our findings revealed a large number of perioperative neuroradiological confounding variables, we reviewed the neuroimaging of a further 20 patients to determine their prevalence. Our literature review revealed that study design, methodological quality and sometimes both diagnostic criteria and findings were inconsistent. The neuroimaging study (pre-operative, n = 10; post-operative, n =10) showed very frequent neuroradiological confounding complications (e.g. hydrocephalus; brainstem compression; supratentorial lesions and post-operative subdural hygroma); the impact of such features had largely been ignored in the literature. Findings from our clinical study showed various degree of deficits in neuropsychological testing (n =1, memory; n = 3, verbal fluency; n = 3, attention; n = 2, spatial cognition deficits; and n =1, behavioural changes), but no patient had full-blown features of CCAS. Our study, although limited, finds no robust evidence of the CCAS following surgery. This and our literature review highlight a need for guidelines regarding study design and methodology when attempting to evaluate neurosurgical cases with regard to the potential CCAS. Neuroimaging study For this part of the study, the neuroimaging findings (CT/MRI) of patients (10 pre-operative cases and 10 post-operative cases) diagnosed with cerebellar tumours, in the Division of Clinical Neurosciences, Western General Hospital of Edinburgh, were randomly selected and evaluated by two independent reviewers Cases of vestibular schwannoma and tumours extending into or from the brain stem were excluded. In addition to the cerebellar/ posterior fossa lesion itself, we were interested in the incidence and nature of associated neuropathological abnormalities.