Acid reflux: when the tests are clean and the burn will not quit.

GERD is often a diagnostic puzzle. Here is how to tell whether your heartburn is coming from your stomach or from a sensitized nervous system.

This page is about understanding the condition and the role the brain and nervous system can play in it. It is not a diagnosis. Your own clinicians know your case.

What GERD is

Between your esophagus (the muscular tube from mouth to stomach) and your stomach sits a ring of muscle, the lower esophageal sphincter. In gastro-esophageal reflux disease, stomach contents, including acid and sometimes bile, flow back up through that ring and irritate the esophagus. The classic symptom is heartburn, a burning discomfort behind the breastbone, often with sour regurgitation. When reflux reaches the throat and voice box it is called laryngopharyngeal reflux (LPR), with hoarseness, throat clearing and a lump-in-the-throat feeling.

Caffeine, nicotine, alcohol, large or fatty meals, and lying down soon after eating all make it worse. A hiatal hernia can contribute. Doctors investigate with endoscopy (a camera down the throat, looking for inflammation), barium X-rays (watching contents reflux) and pH monitoring (measuring acid in the esophagus over a day or more). Treatment is lifestyle change plus acid-suppressing medication, most often a proton pump inhibitor, and for most people it works well.

The neuroplastic contribution

Neuroplastic symptoms are real symptoms produced by learned pathways in the brain and nervous system rather than by ongoing damage in the body. The esophagus is densely wired to the brain, and when that circuit becomes sensitized, the brain can generate a burning, pressing, acid-like sensation whether or not acid is present. The burn is genuine. It is not imaginary and not 'all in your head'. Because the brain can change, it is reversible.

The ATNS Index of Neuroplastic Symptoms describes GERD as a complex diagnostic dilemma and lays out the evidence on each side. Pointing toward an organic cause:

• Tests show the problem: reflux on barium study, inflammation on endoscopy, acid on pH monitoring. The more tests that are positive, the more likely the symptoms are organic.
• Symptoms improve with medication, or with measures such as avoiding caffeine and raising the head of the bed.

The index is honest that the picture can stay unclear: some organic cases do not respond to medication (bile reflux without acid is one reason), and some neuroplastic cases do not improve quickly with mind-body work. The job is to weigh the evidence, not to force a verdict. The mechanism is the one explained in our guide to central sensitization.

What the research shows

Gastroenterology has reached much the same conclusion under different names. People whose heartburn persists on PPIs are split, after pH testing, into three groups: true refractory acid reflux, 'reflux hypersensitivity' (normal acid levels but symptoms that track small physiological reflux events), and 'functional heartburn' (normal acid and no link between symptoms and reflux). Studies cited in a comprehensive review of reflux hypersensitivity find that up to half of PPI non-responders have entirely normal acid exposure. In one series of 67 such patients tested off medication, 58 percent were functional, 18 percent had reflux hypersensitivity, and only 24 percent had true GERD.

A 2018 study of PPI non-responders with normal impedance-pH results found that psychosocial distress and impaired quality of life were associated with symptom severity. In other words, in people whose tests are normal, how bad the heartburn feels tracks stress and wellbeing more than acid.

A 2021 study measured 'esophageal hypervigilance', a learned, anxious focus on sensations in the esophagus, across GERD presentations. Hypervigilance was common in every group and did not differ according to how many days of abnormal acid exposure a person had. Hypervigilance, not acid, significantly predicted symptom severity. Trials of cognitive behavioural therapy for these brain-gut presentations are now under way. Taken together, the research supports the ATNS index's framing: when tests are normal and PPIs fail, the sensitized nervous system is the leading explanation.

Signs the brain may be part of the picture

• Endoscopy, barium study and pH monitoring are normal, or show far less than your symptoms suggest.
• A full-dose PPI, taken correctly for eight weeks, made little difference.
• Symptoms vary a lot from day to day without a clear link to meals.
• Heartburn flares with stress, anxiety, conflict or poor sleep.
• You monitor your chest and throat constantly and feel a jolt of fear with every twinge.

A solution that addresses it

Pain and symptom reprocessing is an approach built for the brain's contribution. It combines education about neuroplastic symptoms, somatic tracking (observing the burn with curiosity rather than alarm, which directly targets hypervigilance), reducing fear and threat around eating and symptoms, a graded return to foods and situations you have been avoiding, emotional awareness and expression, and acceptance and commitment skills. Trained clinicians deliver it, and digital programs are widening access. It sits beside your gastroenterologist's care.

Cindra is a daily AI companion built around these approaches, with daily check-ins, short practices and plain-language lessons for people whose symptoms have a neuroplastic component. If your tests are clean and the burn is not, you can join the waitlist.

What to do next

1. Get properly tested. Persistent heartburn should be assessed by a clinician. Endoscopy and, if needed, pH monitoring off medication tell you whether acid is really the problem. Do not stop a PPI without discussing it, as some people need to taper.
2. Weigh the evidence the way the index does. Count the positive tests and the treatment response on one side, the normal tests, variability, PPI failure and stress on the other.
3. If the balance tips neuroplastic, say so. Ask your clinician whether functional heartburn or reflux hypersensitivity fits, and whether a brain-gut approach makes sense.
4. Start practising. Begin with somatic practices that build calm attention to the chest and throat.

Seek prompt medical care for difficulty swallowing, food sticking, vomiting blood or black stools, unexplained weight loss, or chest pain with sweating, breathlessness or pain spreading to the arm or jaw. Those are not neuroplastic symptoms until a doctor says so.

This article is for general education and is not medical advice, and it does not diagnose or treat any condition. Persistent symptoms deserve a proper medical assessment to rule out disease or injury before a neuroplastic explanation is considered. If your symptoms are new, changing, or come with red-flag signs such as fever, unexplained weight loss, numbness or weakness, chest pain, or loss of bladder or bowel control, see a clinician promptly.