[Prevalence of different groups that comprise endoscopy-negative reflux disease].

Background Data: Endoscopic-negative reflux disease (ENRD) is a heterogeneous population. There are few data regarding the prevalenece of each group and subgroups that constitutes ENRD population.

Objective: To describe the prevalence of the differents groups and subgroups in ENRD.

[Efficacy, diagnostic utility and tolerance of intraesophageal pH ambulatory determination with wireless pH-testing monitoring system].

Background: Conventional catheter-based esophageal pH monitoring system produce discomfort and interference with normal activities and diet. An alternative is the wireless pH system which is more comfortable and offers extended recording periods.

Objective: To know the performance, the clinical utility and tolerability of wireless pH 48 h-monitoring system.