The present invention provides specific methods of using and administering etanercept to improve cognitive function in a human, for both the treatment and prevention of cognitive impairment, or, alternatively, to enhance cognitive function including Alzheimer's Disease, Idiopathic Dementia, and Traumatic Brain Injury. The methods of the present invention include the perispinal administration of etanercept. For the purposes of this patent "perispinal" is to be considered as referring to "perispinal extrathecal;" therefore direct intrathecal administration is excluded. Perispinal administration leads to enhanced delivery of etanercept to the brain in a therapeutically effective amount, via the vertebral venous system and/or the cerebrospinal fluid. Delivery of etanercept to the brain utilizing the methods of the present invention includes the use of the vertebral venous system to deliver etanercept to the brain via retrograde venous flow. Physical maneuvers are used to enhance delivery of etanercept to the brain via this route.