Large Cohort Study Suggests that Tremor May be Common in CIDP, Often Underrecognized

Clinically evident tremor and myoclonus affected roughly 7 in 10 patients with chronic inflammatory demyelinating polyneuropathy (CIDP), according to results from the largest cohort study to systematically characterize these movements in the disease, published in the Journal of Neurology, Neurosurgery & Psychiatry.¹

Conducted by senior author Joke M. Dijk, MD, neurologist at Amsterdam University Medical Center, and colleagues, the study also marked the first large-scale report of myoclonus as a distinct contributor to tremor-like movements in CIDP, a rare autoimmune neuropathy with an estimated incidence of 0.33 per 100,000 person-years.²

Study Overview

The multicenter, cross-sectional study enrolled 124 adults with CIDP diagnosed per 2010 European Federation of Neurological Societies/Peripheral Nerve Society or 2021 European Academy of Neurology (EAN)/PNS consensus criteria,³ recruited from 2 tertiary neuromuscular clinics between 2018 and 2024. Tremor was assessed using the Fahn-Tolosa-Marin Clinical Rating Scale for Tremor (FTM-TRS) and the Tremor Research Group Essential Tremor Rating Assessment Scale (TETRAS), supplemented by standardized video and, in a subset, electromyography (EMG) recordings. Patients were classified as having clinically tremulous movements (CTM) if they scored at least 1 point on FTM-TRS parts A or B.

Key Findings

All told, CTM were identified in 86 of 124 patients (69%; 95% CI, 61%-77%), with a lifetime prevalence of 76%. Notably, more than one-third of affected patients (30 of 86) did not subjectively perceive having tremor, underscoring a recognition gap in routine visits. Movements were universal in the upper extremities (median FTM-TRS-A upper extremity score, 4; range, 1-16) but occurred in the legs in only 20% of cases, and were most prominent during action/intention and postural conditions.

EMG recordings in 37 patients allowed etiologic subclassification: among 30 interpretable recordings, isolated tremor was most common (43%), followed by isolated myoclonus (27%) and mixed tremor-myoclonus features (10%); enhanced physiological tremor accounted for the remainder. Patients with CTM had significantly greater upper-limb sensory impairment (INCAT sensory score) and upper-extremity disability (INCAT-DS-UE) than those without tremor, despite no difference in overall muscle strength, suggesting tremor contributes independently to functional impairment and may confound standard CIDP disability scales.

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Regarding treatment, 46% of patients (22 of 48) reported complete or partial tremor improvement with immunotherapy, most often immunoglobulin. Among a smaller subgroup who received symptomatic therapy, 8 of 10 patients (80%; 95% CI, 44%-98%) using beta-blockers reported partial improvement, while antiepileptics and benzodiazepines showed inconsistent benefit in very small numbers.

Clinical Context and Interpretation

Current EAN/PNS guidelines for CIDP emphasize immunoglobulin, corticosteroids, and plasma exchange as first-line therapies targeting weakness and sensory deficits, with limited specific guidance on tremor management.³ Tremor has historically been underappreciated relative to these hallmark features, with earlier, smaller studies reporting widely variable prevalence (46%-80%) and less description of tremor's clinical characteristics.⁴ The gap between self-reported tremor (65%) and scale-detected CTM in this cohort may support the authors' contention that unstructured assessment likely underestimates true burden.

The authors argued that CIDP-associated tremor is clinically distinct from essential tremor given its male predominance, low rate of family history (18%), lack of alcohol responsiveness, and occasional lower-limb or tongue involvement. They recommended routine tremor monitoring in CIDP, particularly of the upper extremities, and suggest that immunotherapy response be considered before assuming tremor is treatment-resistant.

Limitations and Future Research

Treatment-response data were patient-reported and derived from a subgroup (48 of 86 patients with CTM), introducing potential recall or selection bias. Tremor rating scales used were not formally validated in CIDP, and extremity-specific sum scores were investigator-derived rather than validated instruments. The cohort was drawn from 2 tertiary referral centers, which may limit generalizability, though the authors argued regional referral patterns support external validity. Moreover, the authors called for further work to validate tremor scales specifically in CIDP populations and to prospectively evaluate beta-blockers and immunotherapy sequencing for tremor-predominant disease.

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REFERENCES
1. Pallada G, Baars AE, Jacobs BC, et al. Prevalence, clinical characteristics and treatment response of tremor in chronic inflammatory demyelinating polyneuropathy. J Neurol Neurosurg Psychiatry. Published online September 7, 2026. doi:10.1136/jnnp-2025-338113
2. Broers MC, Bunschoten C, Nieboer D, Lingsma HF, Jacobs BC. Incidence and Prevalence of Chronic Inflammatory Demyelinating Polyradiculoneuropathy: A Systematic Review and Meta-Analysis. Neuroepidemiology. 2019;52(3-4):161-172. doi:10.1159/000494291
3. Van den Bergh PYK, van Doorn PA, Hadden RDM, et al. European Academy of Neurology/Peripheral Nerve Society guideline on diagnosis and treatment of chronic inflammatory demyelinating polyradiculoneuropathy: Report of a joint Task Force-Second revision. J Peripher Nerv Syst. 2021;26(3):242-268. doi:10.1111/jns.12455
4. Saifee TA, Schwingenschuh P, Reilly MM, et al. Tremor in inflammatory neuropathies. J Neurol Neurosurg Psychiatry. 2013;84(11):1282-1287. doi:10.1136/jnnp-2012-303013