https://doi.org/10.1177/1550059420910559 Clinical EEG and Neuroscience 1–7 © EEG and Clinical Neuroscience Society (ECNS) 2020 Article reuse guidelines: sagepub.com/journals-permissions DOI: 10.1177/1550059420910559 journals.sagepub.com/home/eeg Original Article Introduction EEG is commonly used as a diagnostic tool for many neuro- logical and medical conditions, including seizures, epilepsy, cerebrovascular diseases, head injuries, psychiatric diseases, and various encephalopathies. 1 As paroxysmal spells of abnor- mal movements and altered level of consciousness (ALC) are common among hospitalized patients, 2 close examination of EEG patterns alongside clinical history and imaging findings may help determine their underlying etiologies. The associa- tion between certain EEG patterns and circumscribed brain lesions has been described previously. 3 Similarly, correlation between EEG patterns pertaining to various encephalopathies and the corresponding brain magnetic resonance imaging (MRI) findings has been the topic of extensive clinical research. 4-6 However, there is a paucity of studies aiming to establish links between EEG findings and those yielded by other advanced imaging techniques, including magnetic reso- nance spectroscopy, single photon emission CT and positron emission tomography. It has been postulated that slowing of EEG background activity is associated with cortical impairments, whereas subcortical abnormalities can produce delta range slow wave activity (SWA) or triphasic waves (TWs). Similarly, pathologies affecting both cortical and subcortical brain regions can lead to SWA along with background slowing. 7 In the histology and EEG study of patients with diffuse encephalopathy, paroxysmal synchronous discharges (PSDs) with either (spikes, spike and wave complexes, sharp waves [SWs] or SWA that emerged from the background and then returned to lower voltage activ- ity), as well as continuous, irregular, and asynchronous poly- morphic delta activity (PDA) in EEG, were associated with combined cortical and subcortical gray matter pathology, or with white matter pathology. 8 Therefore, the aim of the present study was to determine the correlations between different EEG patterns and underlying structural brain abnormalities in 910559EEG XX X 10.1177/1550059420910559Clinical EEG and NeuroscienceNazish research-article 2020 1 Department of Neurology, College of Medicine, Imam Abdulrahman Bin Faisal University, Dammam, Saudi Arabia Corresponding Author: Saima Nazish, Department of Neurology, College of Medicine, Imam Abdulrahman Bin Faisal University, King Fahd University Hospital, Dammam, 31952, Saudi Arabia. Email: snmohammadali@iau.edu.sa Clinical and Radiological Correlates of Different Electroencephalographic Pattern in Hospitalized Patients Saima Nazish 1 Abstract Objective. The present study aimed to determine the clinical and radiological correlates of different electroencephalographic (EEG) patterns in hospitalized patients. Subjects and Methods. In this retrospective study performed at the Neurology Department, King Fahd University Hospital, Kingdom of Saudi Arabia (KSA), data of 374 patients who underwent EEG were reviewed and analyzed. Results. Presence of focal spike and wave or sharp wave (SW) (P = .00), generalized theta activity (P = .00), generalized delta activity (P = .04), persistent focal slow wave activity (SWA) (P = .003) and asymmetric background (P = .01) in the EEG record was significantly associated with abnormal imaging findings. Specifically, generalized theta delta activity (P = .01) and markedly attenuated EEG activity (P = .007) were associated with presence of cortical lesions; whereas, triphasic waves (TWs) (P = .009), and generalized theta activity (P = .001) were found to be related with presence of subcortical lesions. While, generalized delta activity (P = .01) was the only correlate with extra-axial lesions. Conclusion. At present, certain EEG patterns cannot be precisely correlated with imaging findings, suggesting that intercurrent metabolic, infectious, and/or toxic contributors could be the confounding factors. Nonetheless, when EEG patterns are examined alongside magnetic resonance imaging findings and other clinically relevant data, these might be indicative of a group of diseases in some pertinent situations. Thus, further larger prospective clinical studies that incorporate continuous EEG monitoring, advanced radiology techniques, and laboratory analyses would be beneficial to elucidate their interplay for better firm up the correlations. Keywords electroencephalography, altered level of consciousness, magnetic resonance imaging, cerebral cortex Received November 4, 2019; revised January 16, 2020; accepted January 23, 2020.