One-year dynamic follow-up of patients with reversible ischaemic neurological deficit using quantitative...

The present study was designed to assess the relative value of sEEG and qEEG with brain mapping in the diagnosis of patients with reversible ischaemic neurological deficit (RIND) and the feasibility of these techniques as well as their diagnostic yield in the detection of focal and diffuse changes reflecting the evolution and predicting the prognosis of stroke lesions. Standard (sEEG) and quantitative EEGs (qEEGs) were recorded over a period of one year in 32 patients, aged 40 to 75 years, from a cohort of 54 patients (17 female and 37 male, median age 62 +/- 29.6 years) with a first-ever RIND. A total of 104 sEEGs and 118 qEEGs were performed during the one-year follow-up period. Normal sEEGs were 60 recordings (57.69%) whereas poorly defined low-voltage activity was present in 44 recordings (42.31 +/- 7.50%). No focal changes or asymmetry were found on sEEG. The observed changes in background activity were most probably due to the underlying cerebrovascular disease. The recordings were normal in 72 qEEGs (61%) whereas in 46 qEEGs (39.98 +/- 7.10%) focal changes were detected. Out of the total of 118 recordings with evidence of focal changes in spectrum power increases were found in 91.28% and decreases--in 8.72%, predominantly in the alpha-theta spectrum band. The incidence and localization pattern of the focal findings changed over time. At the beginning site and side were not relevant. The proportion of frequent and unpredictable instability in the symptomatic hemisphere changes was greater immediately following the incident as compared with the changes in the asymptomatic hemisphere, i.e. the discordance increased with the increase in time elapsed since the acute stage. The reverse was true concerning the end of the study period. The importance and the place of sEEG and qEEG with brain mapping in the diagnosis and followup of lesions in RIND patients are critically evaluated.