The following books explain the use of LENS across a number of diagnostic categories:
One study, specifically about LENS, is particularly important because its large sample size (N=100) lends credibility to its utility:
One hundred clients (selected randomly from over 300 cases) ranging in age from 6 to 80 had at least 10 LENS sessions each. Average symptom ratings across 15 major problem areas (e.g., anxiety, mood disturbance, attention problems, fatigue, pain, sleep problems, etc.) showed significant improvement (p<.0001) from beginning to end of treatment. Statistically significant reduction in EEG amplitudes were evident as well.
Citation: Larsen, S., Harrington, K., Hicks, S. The LENS (Low Energy Neurofeedback System): A Clinical Outcomes Study on One Hundred Patients at Stone Mountain Center, New York. Journal of Neurotherapy, Vol 10, No. 2/3, 2006 pp. 69-78.