The common symptoms among adults are:

• low-grade headaches or neck pain that won't go away
• having more trouble than usual with mental tasks (e.g., remembering, concentrating, making decisions)
• slowness in thinking, speaking, acting, or reading
• getting lost or easily confused
• feeling tired all the time, lacking energy or motivation
• changes in sleeping patterns (sleeping a lot more or having a hard time sleeping) * feeling light-headed or dizzy, losing your balance
• increased sensitivity to sounds, light, or distractions
• blurred vision, eyes that tire easily
• loss of the sense of smell or taste
• ringing in the ears
• mood changes (e.g., feeling sad or angry for no reason)

Among children, the symptoms are:

• listlessness or tiring easily
• irritability or crankiness
• changes in eating or sleeping patterns
• changes in the way the child plays
• changes in performance at school
• lack of interest in favorite toys or activities
• loss of new skills, such as toilet training
• loss of balance, unsteady walking