NFL Evolution will feature a guest columnist every Tuesday, each with a different viewpoint of player health and safety from the youth level to pro football.By Dr. Joseph F. Waeckerle, NFL Health Playbook columnistAs parents deal with children who suffer concu sions during athletics Julian Love Jersey , some of them wonder about the neurological problems that occur if the kids do not improve in 2-3 weeks. And what should parents do if this occurs?Scientific studies and consensus documents from health care profe sionals with expertise in concu sion care report that in more than 80 percent of cases, the student-athlete is symptom-free in 7-10 days. Approximately 10-15 percent of patients with a concu sion have a more extended course of complaints that may last four weeks or more. In rare instances (approximately 1-5 percent in some reports), concu sed student-athletes may experience prolonged symptoms lasting for more than one month, with some extending up to one year or more.Certain factors influence the duration of recovery time. Most notable are age and sex differences. In general, the younger the individual, the longer the recovery period. Data also suggests that there is a sex-a sociated difference with females experiencing a more protracted duration of recovery. However, this observation requires further investigation to better define sex-linked complications.A history of previous concu sions appears to predispose the student-athlete to a more protracted course of recover, especially among female student-athletes and younger age groups and when the injury occurs in close proximity to the first concu sion.Although lo s of consciousne s and amnesia are not required criteria for a diagnosis of concu sion, the presence of either may indicate a more severe injury and a correspondingly longer recovery period. A past history of migraine headaches may be a sociated with a greater risk a more protracted recovery.Additionally, in recent studies concu sed student-athletes with no prior history of migraines who developed a "migraine symptom complex" consisting of headaches, visual complaints, dizzine s, nausea and vomiting, sensitivity to noise or light, and balance problems suffered a more prolonged recovery.Other indicators of a more prolonged and complicated recovery proce s include complaints of four or more symptoms concurrently; specific complaints of foggine s, fatigue, or sleep disturbances; persistent balance problems; and any symptoms lasting longer than 10 days, most notably depre sion, lo s in concentration ability, and short-term memory problems.Certain other pre-existing medical conditions and medications can also complicate concu sion management and recovery. Student-athletes with the diagnosis of learning disabilities or a history of depre sion, anxiety, panic disorders, or sleep disturbances may have symptoms similar to those a sociated with concu sions, making evaluation at follow-up substantially more challenging.In addition, medications, especially those prescribed for the treatment of any of the above disorders, may alter concu sive signs or symptoms, adding further to the complexity of ongoing management. The unique genetic code of each person may determine, in part, the response to different types and severity of brain insults but much work needs to be done here.During the ongoing management the concu sed student-athlete or family should report any of these concerns to the attending health care profe sional. If concerns persist, the health care profe sional should consult with other concu sions specialists to explore alternate management and recovery strategies. Without a "gold standard" for diagnosis of a concu sion and monitoring of progre s, clinical criteria remain the benchmark for diagnosis, progre s, and recovery. Recent reports utilizing sophisticated neuroimaging suggest that complete recovery at the cellular and subcellular level may not occur for a longer period post-injury than is demonstrated by the normalization of clinical criteria.However, more work certainly needs to be done to correlate sophisticated testing with these clinical criteria. This very preliminary work does prompt caution in difficult cases. If there are any concerns regarding progre s or recovery, consultation with additional concu sion specialists and the prescribing of "more time" is advisable.Dr. Joseph F. Waeckerle is clinical profe sor of emergency medicine at the University of Mi souri-Kansas City School of Medicine. He also is editor emeritus of Annals of Emergency Medicine. He has practiced Emergency Medicine and Sports Medicine and has been a team physician at the grade school, high school, college, and profe sion level for over 30 years. He currently serves on the NFL Head, Neck, and Spine Injury Committee and the Mackey White Brain Injury Committee of the NFL Players A sociation. Jon Runyan Jersey