<p>When alpha frequency is slower by 1 Hz or more (and localized in one hemisphere), it may indicate a focal abnormality (Markand, 1990) warranting a neurological consult; a difference of 1.5 Hz or more is particularly worrisome (Duffy, et al., 1989).&nbsp; &nbsp;Any hemispheric amplitude difference in alpha between the two sides of more than 50% is considered significant (Hughes, 1994), Furthermore, because alpha rhythm is usually of higher amplitude on the right side (for right-handed people), a decrease of even 35% on the right may be significant (Duffy et al., 1989).&nbsp; Lastly, Frontal asymmetries in alpha have been found to be significant markers in depression.<br></p>