Here are the main takeaways from the co-presentation by Dr. Donald Nixdorf and Dr. Suzie Bergman:

1. Diagnostic Challenges

  • Facial pain can be caused by TN (a nerve condition) or TMD (muscle/joint issues), and the symptoms often overlap. Wrong diagnosis can lead to inappropriate treatments—dental, medical, or surgical—that may not provide relief.
  • The ‘telephone game’ analogy used by Dr. Nixdorf highlighted how clinical information can be miscommunicated, leading to an incorrect final diagnosis.

2. Patient Perspective & Comprehensive Care

  • Dr. Bergman emphasized the importance of acknowledging patient experience, as even evidence-based procedures can fall short without patient-centered care. She shared her journey, showing the long-term effects of misdiagnosis and mistreatment.

3. Needed Improvements in Care

  • Measurement of Diagnosis Accuracy: There is a need to formally assess how effective current diagnostic tools are for TN, as this is not well-studied.
  • Overlapping Conditions: Many TN patients may also have TMD or other chronic pain conditions, complicating diagnosis and management.
  • Detailed Patient Histories: Collecting comprehensive patient information is essential to avoid misdiagnosis and ensure the best treatment path.

Here is the full documentation from their presentation, plus a more technical version below:

PRESENTATION SUMMARY
Drs. Don Nixdorf (University of Minnesota) and Suzie Bergman (Pacific Northwest University School of Dental Medicine) gave a co-presentation about a problem that affects many people living with facial pain: the wrong diagnosis. Many patients are told they have trigeminal neuralgia (TN) when they actually have a different condition, such as a temporomandibular disorders (TMD) — and the reverse also happens. The wrong diagnosis leads to wrong treatments, sometimes including dental treatment, medications or surgeries that don’t help.

TN and TMD can look similar from the outside. Both cause facial pain. But the underlying problems are different: TN is a nerve condition with sudden, severe, electric-shock-like pains that are triggered, while TMD involves the muscles and joints around the jaw, often producing pain that comes with chewing or talking (also common triggers for TN). Patients with one condition often use the same words as patients with the other, which makes it hard for clinicians to tell them apart from the conversation alone.

To make the point clearly, Dr. Nixdorf opened the talk with a “telephone game”: he gave one attendee a sentence to whisper around the room. By the end, the original sentence (“Neuropathic pain is a neuropathy, but not a neuritis…”) had become “TMD is not inflammatory” — completely different. That, he said, is exactly what happens with diagnosis: information gets distorted from speaker to listener, and the diagnosis at the end of the chain may not match what the patient actually has.

Dr. Bergman shared her own story as a patient. After a serious accident as a teenager, she eventually needed titanium artificial jaw joints. She was a dental student and had the benefit of being at a teaching institution, and still opinions were varied about how she should be treated, and many recommended treatments were not evidence-based. This is an unfortunate reality for many patients with TMDs. She showed photos of her own face changing through the years and the toll that misdiagnosis and mistreatment have taken — a reminder that a procedure can be technically successful while the patient still suffers. Her message: the patient is the expert on their own pain, and good care must combine the science with what the patient actually experiences.

The take-home messages were three: first, no one has measured how accurate our current TN diagnosis tools really are, and that needs to change. Second, TN patients may also have other overlapping pain conditions — including TMDs — and this affects how they describe their pain. Third, we need to be more comprehensive with collecting details from patients to help with differential diagnosis process, so that the right patients get the right diagnosis and treatments.

Graduate-Level Summary (for scientists, clinicians, and industry CSOs)

Nixdorf and Bergman delivered a co-presentation challenging the field on the unaddressed measurement problem at the heart of trigeminal neuralgia diagnosis: the diagnostic instruments in routine clinical and research use have never had their error rates established, and the rate of misdiagnosis between TN and temporomandibular disorders (TMD) is high in both directions.

Framing exercise. Nixdorf opened with a “telephone-game” demonstration. He passed a sentence around the audience starting with one attendee and another recorded what he heard at the end. The original — “Neuropathic pain is a neuropathy, but not a neuritis, but it is a neuralgia by description and not definition or diagnosis” — became “TMD is not inflammatory” by the time it reached the last of 22 attendees. Nixdorf used the result to motivate his ontology argument: diagnosis is fundamentally a communication problem, and unambiguous operationalized criteria are what military command structures use precisely to keep meaning intact across a chain of speakers.

Diagnostic process and item generation. Nixdorf walked through the formal item-selection process underlying the TMD diagnostic criteria his group has built (Schiffman et al., 2014, with subsequent revisions). The current operationalized TMD criteria show sensitivities often >0.9 and specificities >0.95 — a rare standard in pain diagnostics, achieved through a 100-page operationalization manual with images, videos, and standardized prompts. Fifteen distinct TMD diagnoses are produced.

Critique of TN diagnostic criteria. The ICHD-3 criteria for TN (13.1.1.) is well excepted, not operationalized and not tested, therefore; the propensity of making diagnostic errors is unknown. This has implications related to both research and clinical care. Using examples from the literature, the “Rushton criteria” used in a widely cited epidemiology article requires documented evidence of physician-evoked pain, and by today’s standard this would result in an under reporting of incidence (i.e., falsely negative diagnoses). He framed this as analogous to the “probable migraine” history: clinicians eventually pushed back on the headache classification because the strict definition was missing real cases, exemplifying a pain disorder that was well known, well accepted and intensity studied yet the diagnostic accuracy was not evaluated. The impact of such diagnostic errors in TN, being a rare disease, and more profound because the numbers of patients in studies is much smaller than other pain-related disorders. Given this, diagnostic criteria-too-lax (false positives contaminating mechanistic studies) and criteria-too-strict (under-representation in epidemiology and clinical applications) are likely bigger concerns that what is currently being realized.

Audience input from Sindou. Marc Sindou — a participant in the international headache society classification process — pushed for two specific revisions: (1) emphasize history of pain at disease onset before anticonvulsant exposure, since by the time surgical patients are seen, deep persistent pain often masks the original paroxysmal character; and (2) include first-line anticonvulsant (carbamazepine) responsiveness as a criterion. Sindou also reported a clinical observation that ~35% of patients with grade-1 NVC (simple contact) are surgical failures or recurrences — challenging the idea that demonstrated NVC is the sole diagnostic anchor.

Clinical-prevalence framing and TN-TMD overlap. In the University of Minnesota orofacial pain clinic, ~1.3% of new patient visits carry a TN diagnosis; >70% of these patients diagnosed with TN have concomitant TMD (typically myofascial pain). Nixdorf delineated four populations driving misdiagnosis: (a) primary TMD patients misdiagnosed as TN (often because they reach for McGill descriptors with high punishing affect — “lightning,” “shooting”); (b) primary TN patients with secondary TMD that develops as the patient alter how they use their masticatory musculature in response to having TN; (c) new onset TN in patients that had pre-existing TMD, and (d) new onset TMD following neurosurgical procedures that is misinterpreted as being TN. His clinical claim: in patients with TN and comorbid TMD, which is likely responsible for what others classify as concomitant background pain, understanding the inter-relationship and treating both disorders results in markedly improved outcomes.

Patient-perspective component (Bergman). Bergman delivered a personal narrative grounded in evidence-based medicine’s three-leg framework (scientific evidence + clinician expertise + patient needs/preferences) and the “patient is the expert” framing. She showed photographs of her own face over time documenting the cumulative anatomic and functional consequences of multiple jaw surgeries, including a titanium TMJ (a procedure performed in approximately 1,000 patients/year), with morphological asymmetry, scarring, ipsilateral lip deviation, and an eyebrow paralysis. She argued for replacing “pain catastrophizing” with “hypervigilance” as a less stigmatizing descriptor of the central-sensitization phenomenon. Her overall thesis: surgical or technical “success” with continued patient suffering is not success.

Q&A — carbamazepine response as diagnostic marker. A spirited debate engaged Basbaum (interested in mechanism: “what’s special about carbamazepine — it doesn’t work in back pain or CRPS — understanding mechanism of action will tell you something about the uniqueness of TN”) and Burchiel (cautioning that early-positive then late-negative carbamazepine response may be a false-positive placebo signal). Bergman/Nixdorf: TN2 patients also respond to carbamazepine, complicating its specificity as a discriminator. Nixdorf proposed continuing the discussion at a working lunch.

Three take-home messages. (1) Diagnostic accuracy on TN has not been assessed; methods to do so are needed. (2) Chronic overlapping pain disorders are the norm and substantially affect TN presentation; future research must take this into account in defining outcomes. (3) More detailed phenotyping is needed across the full spectrum from ecological-momentary-assessment minute-to-minute data through natural-history observation through biopsychosocial integration — none of which currently exists for TN despite their established value in adjacent pain conditions.