The primary objective of the study is to describe the value of interhemispheric asymmetry (ASYM), during the different intra- and peri-operative phases, in those patients who develop or do not develop post-operative delirium (POD) during the first 30 post-operative days and postoperative cognitive disfunction (POCD) in the first 90 post-operative days, in a population undergoing head&neck and plastic surgery with a priori increased probability of POD.

Values of the study variables will be extract in these specific moments (considering a delay of thirty seconds between the in vivo phenomenon and the instrument): (t1) BIS probe application (t2) 60" before GA administration (t3) 60" after myoresolution (t4) intubation (t5) surgical incision (t6) end of ipnosis (t7) 10 minutes after extubation. Daily follow-up for the first five post-operative days is performed in order to verify the onset of POD and a telephone follow-up at thirty and ninety post-operative days in order to verify the onset of POD / POCD.

CAM scale will be used for the diagnosis of POD; while for the diagnosis of POCD, 6-CIT test will be used, the EQ50 test in the case of tracheostomized patients.

Inclusion Criteria:

-Patients, undergoing head&neck surgery, who have at least 3 of the following criteria (to establish "a priori" increased risk of POD):

• Age> 70;
• Male sex; or ASA III;
• Smoker;
• High blood pressure;

Exclusion Criteria:

• ASA IV, V or ASA IE, IIE, IIIE (patients with anesthetic risk ASA>III and those undergoing urgent-emergency surgery will be excluded from the study);

• Past positive medical history for:

  • Stroke;
  • Dementia;
  • Cerebral aneurysm;
  • Intracranial mass;
  • Head trauma;
  • Epilepsy;
  • Diabetes mellitus;
  • Previous neurosurgical intervention;
  • Psychiatric illnesses requiring chronic treatment;

• Patients undergoing surgery in the previous two weeks;

• Patients whose hospitalization duration is estimated to be less than five days;

• Lack of understanding of the Italian language or English;

• Age <18 years.

The study plans to enroll all patients undergoing head&neck surgery and plastic surgery, who meet the inclusion criteria. Patients will be screened and definitively enrolled after checking the inclusion and exclusion criteria. The study population, therefore, is represented by a minority of patients undergoing head&neck and plastic surgery, who have "a priori" increased risk of developing POD.

The setting of the proposed study is the operating theaters of the operating block where the Anesthesia and Pain Therapy service is located, directed by Prof. Rita Maria Melotti, in pavilion 5 in the Policlinico Sant'Orsola-Malpighi in Bologna, Italy.