Diagnostic significance of déjà vu phenomenon in clinical presentation of the brain tumors

The incidence of brain tumors (BT) in Russia is 7.5 per 100000.  Déjà vu (French) (DV) phenomenon may present as the one of the BT symptom. DV (French «already seen») is a mental disorder associated with the perception of reality, when an unknown, completely new situation seems to be familiar and already withnessed by the patient. Aim: to determine the characteristics and prevalence of DV in patients with BT. Materials and methods: The study group consisted of 197 subjects (mean age 27.1±13.2 years; 47% men). First subgroup included 139 healthy subjects, 2nd subgroup consisted of 58 patients with BT, that were selected from 1772 patients with BT and seizures. All subjects completed special questionnaire to identify various characteristics of the DV (frequency, duration, emotional background), Cambridge depersonalization questionnaire; video-EEG study was performed. We used specific statistical methods and programs for analysis (confidence intervals calculation, Mann- Whitney test, etc.) The results were considered significant with p≤0.05)). Results: DV was manifested in 97% of healthy subjects. DV occured in 3.3% patients with BT and epileptic seizures. The phenomenon was seen more frequently in astrocytomas (50%, p=0.002) of right (72%, p=0.0001) temporal lobe and was associated with generalized seizures (54%) and olfactory hallucinations (24%). Patients with BT had significant differences in the characteristics of DV compared to the healthy subjects: the frequency of DV up to several times per day (Z=5.58; p=0.000001); duration – some minutes (Z=-2.78; p=0.004); DV is associated with negative emotions (Z=-2.35; p=0.02) and fear (Z=3.81; p=0.00002). Conclusions: The key to diagnosis is not only the fact of DV experience, but also the changes its characteristics (increased frequency and duration, etc.).