The introduction of neurostimulation procedures for chronic drug-resistant primary headaches has offered new hope to patients, but has also introduced new problems. The methods to be used in assessing clinical outcomes and monitoring treatment efficacy need careful attention. The International Headache Society guidelines recommend that treatment efficacy should be monitored by getting patients to report the number of attacks per day, in a headache diary. The headache diary is a fundamental instrument for objectively assessing subjective pain in terms of headache frequency, intensity and duration and analgesic consumption. The huge discrepancy sometimes reported between patient satisfaction and headache improvement suggests that patient satisfaction should not be a primary efficacy endpoint, and more importantly should not be put forward as an argument in establishing the efficacy of highly experimental neurostimulation procedures.