Loss of fine motor function correlates with ataxia and decline of cognition in cerebellar tumor survivors

Abstract

Motor and cognitive function losses resemble handicaps in pediatric posterior fossa tumor survivors. Several factors determine type and extent of impairment. We quantified loss of fine motor function and its association with ataxia and intelligence in patients with and without adjuvant treatment. Fine motor function, extent of ataxia and cognitive function were assessed in 25 medulloblastoma (MB) and 16 cerebellar pilocytic astrocytoma (PA) patients at least 1 year after completion of therapy. Kinematic parameters (speed, automation, variability, and pressure) of different movement complexity levels were investigated employing a digitizing graphic tablet. Degree of ataxia was quantified using the International Cooperative Ataxia Rating Scale and cognition was determined using the Wechsler Intelligence Scale. Kinematic parameters of low and high complexity tasks as well as ataxia of MB patients were strongly impaired. Fine motor impairment was weaker in PA patients, but still evident in the complex task of writing. Ataxia was significantly more pronounced in medulloblastoma patients. Young age and short recovery time correlated significantly with impaired kinematic parameters. Ataxia was strongly associated with inferior fine motor function. Cognition, especially performance IQ, was associated with dysfunctional kinematic parameters. The digitizing tablet detected extent of fine motor function loss at varying levels of complexity of pediatric cerebellar tumor survivors. This tool promises to be a potentially effective method for measuring fine motor function in clinical trials and may be helpful in studying mechanisms of neurotoxicity in posterior fossa tumor patients as well as success of rehabilitation.