Postoperative cognitive dysfunction (POCD) is a disease with restricted cognitive memory function and intellectual skills, which occurs after surgery with and without anesthesia. The POCD strongly depends on patient's age and the surgical operation type. The anesthesia procedure plays a pivotal role as well and regarding the current knowledge it is still uncertain which technique matches the lowest risk. Elevated stress level accompanied with regional anesthesia procedures are accused to cause POCD in elderly patients. The investigators address the question weather regional or general anesthesia leads to a pronounced POCD in dependence of stress incidence.

Postoperative cognitive dysfunction (POCD) is a disease with restricted cognitive memory function and intellectual skills, which occurs after surgery with and without anesthesia. The limiting cognitive ability leads to a lack of quality of life for a lot of patients. The POCD strongly depends on patient's age and the surgical operation type. In aged adults the incidence of POCD after one week following surgery is 25,8%. Risk factors for the development of a POCD is beside age less education and a reduced cognitive reserve. However, the anesthesia procedure plays a pivotal role as well and regarding the current knowledge it is still uncertain which technique matches the lowest risk. Elevated stress level accompanied with regional anesthesia procedures are accused to cause POCD in elderly patients. This fact leads to the question if a general anesthesia technique has a lower stress level and consequently leads to a reduced risk for a POCD development. Likewise the investigators address this hypothesis and analyze cognitive function following both anesthesia techniques separately in elderly patients.

Inclusion Criteria:

• Patients within 50-85 years of age both gender.

Exclusion Criteria:

• Patients under 50 years of age or older than 85 years of age.
• Preexisting neurological, neuropsychological deficits or diseases, e.g. cerebral insult or epilepsy.
• Preexisting neurological, neuropsychological medication, preexisting neuromuscular diseases.
• Alcohol- and drug abuse. Postoperative complications, pain and time shifts within the test protocol.

Patients recruted at the University Hospital Erlangen prior surgery. Anesthesia procedure eigther in regional or general manner.