title: Impact on cognitive functions following gamma knife radiosurgery for cerebral arteriovenous malformations.
abstract: BACKGROUND
  Radiosurgery is an alternative to surgical resection of arteriovenous malformation (AVM). Very few studies have addressed the concern of radiation injury to the brain and its attendant adverse effects on cognitive function.
  
  
  METHODS
  This prospective study included all patients who underwent gamma knife radiosurgery (GKRS) at our institute for cerebral AVM between 2006 and December 2008 (n = 34). All patients underwent neuropsychological evaluation before the procedure. Neuropsychological evaluation was repeated in eighteen patients 2 years following GKRS. Clinical outcome, AVM obliteration, and factors influencing outcome were analyzed in these eighteen patients.
  
  
  RESULTS
  Before GKRS, more than 50% had significant impairment of neuropsychological functions compared to normal population norms. 66.6% achieved the excellent radiosurgical outcome. At 2 years follow-up, patients showed varied improvement in neuropsychological function in various categories. Pretherapeutic median value for percentage perseverative responses was 26.5 and at follow-up, it reduced to 18.2 (P = 0.039). Set shifting improved in 11 patients (61.1%), remained same in 5 patients (27.7%), and deteriorated in two patients (11.1%). Patients with a higher Spetzler-Martin grade AVM demonstrated a significantly more favorable shift in follow-up test values for set shifting function (P = 0.021). Patients with postradiation imaging changes had lesser tendency to improve in neuropsychological performance at follow-up.
  
  
  CONCLUSIONS
  GKRS has no clinically harmful effect on cognitive and neuropsychological functioning in patients with brain AVM. On the contrary, there is an improvement in majority of patients at 2 years following radiosurgery when nidus is obliterated.
authors.affiliation: Department of Neurosurgery, National Institute of Mental Health and Neurosciences, Bengaluru, Karnataka, India.
authors.forename: A
authors.initials: A
authors.lastname: Raghunath
authors.affiliation: Department of Clinical Psychology, National Institute of Mental Health and Neurosciences, Bengaluru, Karnataka, India.
authors.forename: Niranjana
authors.initials: N
authors.lastname: Bennett
authors.affiliation: Department of Neurosurgery, National Institute of Mental Health and Neurosciences, Bengaluru, Karnataka, India.
authors.forename: Arivazhagan
authors.initials: A
authors.lastname: Arimappamagan
authors.affiliation: Department of Neurosurgery, National Institute of Mental Health and Neurosciences, Bengaluru, Karnataka, India.
authors.forename: Dhananjaya I
authors.initials: DI
authors.lastname: Bhat
authors.affiliation: Department of Neurosurgery, National Institute of Mental Health and Neurosciences, Bengaluru, Karnataka, India.
authors.forename: Dwarakanath
authors.initials: D
authors.lastname: Srinivas
authors.affiliation: Department of Biostatistics, National Institute of Mental Health and Neurosciences, Bengaluru, Karnataka, India.
authors.forename: K
authors.initials: K
authors.lastname: Thennarasu
authors.affiliation: Department of Clinical Psychology, National Institute of Mental Health and Neurosciences, Bengaluru, Karnataka, India.
authors.forename: R
authors.initials: R
authors.lastname: Jamuna
authors.affiliation: Department of Neurosurgery, National Institute of Mental Health and Neurosciences, Bengaluru, Karnataka, India.
authors.forename: Sampath
authors.initials: S
authors.lastname: Somanna
keywords: Arteriovenous malformation; cognitive effects; outcome; postradiation edema; radiosurgery