Use of Jonkman et al. Score for Visual Quantification of Electroencephalography as a Tool to Assess Disease Severity in Cortical Dementias

OBJECTIVES: To study electroencephalography (EEG) changes in patients with cortical dementias (Alzheimer's disease [AD] and frontotemporal dementia (FTD). (1) To correlate EEG changes with clinical severity of dementia as assessed by rating scales. (2) To correlate global gray matter volume (GGMV) with EEG scores and clinical severity rating scales. PATIENTS AND METHODS: This is a prospective cross-sectional study involving patients fulfilling the criteria for Probable AD and FTD. A total of thirty patients (20 = FTD, 10 = AD) underwent detailed neuropsychological evaluation, dementia rating scales, EEG, and magnetic resonance imaging. Five EEG parameters were acquired and each parameter is scaled and the total score was compared with neuropsychological parameters and GGMV. RESULTS: For FTD, the mean age of patients was 58.85 ± 6.87, mean mini-mental state examination score was 13.30 ± 6.33, Hindi mental state examination: 14.35 ± 6.28, mean grant total EEG score (GTES): 7.80 ± 5.39, and mean GGMV: 464580.76 ± 52127 mm(3) and for AD, the same were 69.50 ± 8.59, 12.90 ± 5.56, 14.20 ± 5.31, 9.80 ± 5.29, and 483208 ± 47371.5 mm(3), respectively. GTES for mild, moderate, and severe FTD are 2.33 ± 1.528, 6.00 ± 3.162, and 10.70 ± 5.677 and for AD it is 4, 7.50 ± 4.041, 15 ± 1.414, respectively. The GGMV for mild, moderate, and severe FTD was 511836 ± 45005, 492693.1 ± 50624, and 430725 ± 30744 and for AD it is 527217.3 ± 36171, 503598 ± 3006, and 440812 ± 33911. DISCUSSION: The most common EEG abnormalities in cortical dementias are reduced frequency of rhythmic background activity. There is a significant correlation between GTES and dementia severity and global gray matter volume but the proportional correlation with GTES and volumetric scores is not significant. CONCLUSION: EEG is a cheap and sensitive and easily available tool to assess disease severity in patients with cortical dementias and thus helps in planning the type of rehabilitatory interventions and prognostication.