Audio-visual information supplied by electronic media is rapidly beginning to occupy a greater part of our information environment than natural audio-visual information While positive effects on the user's brain are possible through contact with visual media, it is impossible to deny that negative effects are also possible To develop a basic and effective method to physiologically assess how visual media affects the human brain, we classified and investigated considerable data in this field, referring to outcomes of studies on sound amenities An α-EEG (Electroencephalogram) indicated assessment method is developed Its effectiveness is examined in a comparison between a High-Definition format and an NTSC format Results suggest the effectiveness of the method with statistical significance