Radboud Oral Motor Inventory for Parkinson’s Disease

Abstract

The Radboud Oral Motor Inventory for Parkinson’s Disease (ROMP) is a standardized, patient-reported outcome measure designed to assess the presence, severity, and functional impact of speech, swallowing, and saliva control impairments in individuals diagnosed with Parkinson’s disease (PD). Developed by Johanna G. Kalf, Bert J. M. de Swart, Bastiaan R. Bloem, and Marten Munneke at the Radboud University Medical Center, the instrument responds to the critical clinical need for a multidimensional tool grounded in the International Classification of Functioning, Disability and Health (ICF) framework. The complete ROMP encompasses 23 self-administered items organized across three distinct subscales: ROMP-swallowing (7 items), ROMP-saliva (9 items), and ROMP-speech (7 items). Each item is rated on an anchored 5-point Likert scale ranging from 1 (normal / no impairment) to 5 (severe impairment / inability to perform function).

Psychometric evaluations demonstrate that the ROMP possesses robust measurement properties. Across independent clinical trials and validation studies, the instrument exhibits high internal consistency, with Cronbach’s alpha coefficients ranging from .86 to .94 across subscales, and excellent test-retest reliability (intraclass correlation coefficients generally exceeding .85). Construct and convergent validity have been confirmed via substantial correlations with the MDS-Unified Parkinson’s Disease Rating Scale (MDS-UPDRS), the Swallowing Quality of Life questionnaire (SWAL-QOL), and instrumental swallowing examinations such as fiberoptic endoscopic evaluation of swallowing (FEES). The primary clinical module, ROMP-swallowing, provides a rapid and sensitive screening tool for oropharyngeal dysphagia, aspiration risk, and related nutritional or social restrictions. The ROMP serves as an essential assessment in both routine clinical neuro-rehabilitation and clinical trials evaluating pharmacologic, surgical, or behavioral interventions.

Keywords

Parkinson’s disease, Radboud Oral Motor Inventory for Parkinson’s Disease, ROMP, dysphagia, deglutition disorders, sialorrhea, hypokinetic dysarthria, patient-reported outcome measures, ICF framework, psychometric validation

Authors

The Radboud Oral Motor Inventory for Parkinson’s Disease was developed by an interdisciplinary team of clinical researchers, speech-language pathologists, and neurologists affiliated with the Department of Rehabilitation and the Parkinson Center Nijmegen (ParC) at the Radboud University Medical Center in Nijmegen, The Netherlands:

• Johanna G. (Hanneke) Kalf, PhD, SLP: Associate Professor and Senior Researcher in Speech-Language Pathology, Department of Rehabilitation and Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands. Lead investigator in oral motor disorders and dysphagia in neurodegenerative diseases.
• Bert J. M. de Swart, PhD, SLP: Department of Rehabilitation, Radboud University Medical Center, Nijmegen, and Research Group Neurorehabilitation, HAN University of Applied Sciences, Nijmegen, The Netherlands. Specialist in speech pathology and motor speech disorders.
• Bastiaan R. Bloem, MD, PhD, FRCPE: Professor of Neurological Movement Disorders, Department of Neurology, Radboud University Medical Center, and Co-founder of ParkinsonNet, Nijmegen, The Netherlands. Internationally recognized neurologist specializing in Parkinson’s disease and movement disorder management.
• Marten Munneke, PhD, PT: Department of Neurology and Department of Rehabilitation, Radboud University Medical Center, and Director of ParkinsonNet, Nijmegen, The Netherlands. Expert in healthcare innovation and specialized allied health networks for neurodegenerative conditions.

Purpose

Oropharyngeal dysfunction represents one of the most pervasive, debilitating, and potentially lethal complications of Parkinson’s disease. Progressive neurodegeneration within the basal ganglia, substantia nigra, and brainstem swallowing centers yields a constellation of cranial sensorimotor deficits. These include dysphagia (impaired swallowing), hypokinetic dysarthria (reduced vocal loudness, monotonous pitch, and imprecise articulation), and sialorrhea (anterior drooling or intraoral pooling of saliva caused by reduced spontaneous deglutition frequency). Despite an estimated dysphagia prevalence exceeding 80% in advanced disease stages, patients frequently exhibit impaired sensory awareness or underreport their difficulties until catastrophic complications—such as aspiration pneumonia, choking episodes, severe malnutrition, or chemical dehydration—emerge.

Historically, clinicians relied either on time-intensive objective assessments (e.g., videofluoroscopic swallowing studies [VFSS] or fiberoptic endoscopic evaluation of swallowing [FEES]) or broad functional indices that lacked specificity for oral motor complaints. The primary objective behind developing the ROMP was to establish a standardized, highly practical, patient-reported outcome measure specifically tailored to the unique clinical phenotype of Parkinson’s disease. The tool aims to bridge the gap between objective physiological pathology and the patient’s subjective daily functional lived experience.

Clinically, the ROMP serves three distinct purposes:

• Diagnostic Screening: Identifying early, subtle manifestations of oral motor decline—such as prolonged meal durations, difficulty swallowing pills, or coughing during liquid intake—prior to overt clinical decompensation.
• Therapeutic Planning: Directing tailored interventions by distinguishing whether impairments are predominantly driven by neuromuscular degradation (e.g., masticatory inefficiency), autonomic/deglutitive imbalance (e.g., sialorrhea), or phonatory/articulatory decay (e.g., speech intelligibility).
• Longitudinal Monitoring: Tracking disease progression and evaluating the therapeutic efficacy of speech-language pathology interventions (e.g., Lee Silverman Voice Treatment [LSVT], Expiratory Muscle Strength Training [EMST]), levodopa dosage titrations, botulinum neurotoxin injections for salivary control, or deep brain stimulation (DBS).

Psychological Construct

The psychological and physiological constructs measured by the ROMP reflect the multidimensional nature of oral motor function in neurodegenerative illnesses. Rather than treating oral motor decline solely as a biomechanical deficit, the instrument assesses how neuromuscular degradation intersects with cognitive adaptation, behavioral compensation, emotional distress, and social engagement. The instrument operationalizes these challenges across three primary domains:

1. ROMP-Swallowing (Dysphagia Construct)

The deglutition subscale captures the continuum of swallowing pathology, spanning mechanical oral-phase deficits, pharyngeal clearance delays, protection of the laryngeal vestibule, and psychosocial participation restrictions:

• Masticatory and Oral Preparatory Function: Assessed via item 1 (chewing solid foods). Evaluates muscular fatigue, bradykinesia of the masseter and lingual musculature, and the need for involuntary dietary texture modification (e.g., transitioning from raw vegetables to pureed or liquid diets).
• Pharyngeal Clearance and Residue Sensation: Assessed via item 2 (sensation of food sticking in the throat). Reflects delayed pharyngeal transit time, incomplete epiglottic deflection, and reduced tongue-base retraction, resulting in vallecular or pyriform sinus residue.
• Laryngeal Penetration and Aspiration Vulnerability: Assessed via items 3 and 4 (choking or coughing during liquid ingestion vs. solid food intake). This distinguishes between impaired laryngeal vestibule closure velocity (which predisposes individuals to thin liquid aspiration) and mechanical pharyngeal obstruction or sensory clearing deficits.
• Pharmacological Adherence Dynamics: Assessed via item 5 (pill dysphagia). Captures difficulty swallowing solid oral medications, a profound risk factor in PD given that inconsistent levodopa absorption can precipitate severe motor fluctuations, freezing, and ‘off’ states.
• Efficiency and Energy Expenditure: Assessed via item 6 (meal duration). Quantifies bradykinesia of ingestion, where eating becomes an exhausting task lasting over an hour, leading directly to secondary caloric deprivation, cachexia, and caregiver strain.
• Psychosocial Participation and Dining Hedonics: Assessed via item 7 (enjoyment of eating and social dining). Evaluates the affective and relational consequences of dysphagia, including the fear of public choking, embarrassment over adaptive feeding strategies, mealtime-related anxiety, and subsequent social isolation.

2. ROMP-Saliva (Sialorrhea Construct)

The saliva subscale operationalizes anterior and posterior drooling. Sialorrhea in Parkinson’s disease rarely stems from salivary hypersecretion; instead, it is driven by a reduction in spontaneous, automatic swallowing frequency, paired with stooped posture and involuntary mouth opening. The construct measures daytime social embarrassment, skin irritation, nocturnal wetness of pillows, and the constant need to wipe the mouth or carry tissues, capturing substantial distress and stigmatization.

3. ROMP-Speech (Hypokinetic Dysarthria Construct)

The speech subscale measures communicative disability resulting from hypophonia (reduced vocal volume), vocal tremor, palilalia, tachyphemia, and imprecise consonant articulation. It captures both functional intelligibility (being asked to repeat oneself, difficulties communicating in noisy environments, or speaking over the telephone) and the psychosocial frustration associated with communicative withdrawal.

Theoretical Framework

The conceptual architecture of the ROMP is rooted in the International Classification of Functioning, Disability and Health (ICF) promulgated by the World Health Organization (WHO, 2001). Traditional neuro-rehabilitation assessments heavily favored isolated physiological impairments, failing to capture how an anatomical deficit translates into daily activity limitations and broad societal participation restrictions.

Furthermore, the ROMP integrates theoretical principles from Cognitive Neuropsychology and Perceptual Sensorimotor Integration. Parkinson’s disease impairs proprioceptive feedback loops; patients often display severe vocal hypophonia or pharyngeal residue without an internal awareness of the deficit. By providing concrete, behavioral anchors (e.g., “eating takes 30 to 45 minutes” or “I eat mashed or soft food”) rather than abstract, unanchored rating scales, the ROMP mitigates sensory agnosia and calibrates the patient’s subjective reporting against observable functional criteria.

Validity

Validation studies of the ROMP have demonstrated excellent psychometric validity across multiple language adaptations and clinical settings:

Content and Face Validity

During initial instrument development, Kalf and colleagues (2007, 2011) conducted item generation based on systematic literature reviews of existing swallowing and speech instruments, combined with rigorous focus groups of speech-language pathologists, movement disorder neurologists, and patients with PD. Items were subjected to clinical review panels to ensure comprehensive coverage across all ICF domains while keeping patient burden to a minimum.

Construct and Convergent Validity

Convergent validity has been evaluated against both patient-reported quality of life tools and instrumental diagnostic standards:

• Swallowing Quality of Life (SWAL-QOL): The ROMP-swallowing subscale demonstrates strong negative correlations with the SWAL-QOL total score (Pearson’s $r = -.70$ to $-.82$, $p < .001$), indicating that higher ROMP scores (greater functional impairment) accurately align with diminished swallowing-related quality of life.
• MDS-UPDRS Motor Experiences of Daily Living: Moderate to high correlations are observed between ROMP subscales and the relevant items of the MDS-UPDRS Part II (Speech item 2.1, Saliva and Drooling item 2.2, and Chewing and Swallowing item 2.3), with Spearman rank correlation coefficients ranging from $rho = .65$ to $.78$.
• Instrumental Swallowing Examinations (FEES / VFSS): Scores on ROMP-swallowing correlate significantly with the Rosenbek Penetration-Aspiration Scale (PAS) and objective pharyngeal residue scales. Patients scoring $ge 13$ on the ROMP-swallowing subscale have a substantially elevated odds ratio of exhibiting silent penetration or aspiration under endoscopic evaluation.

Discriminant and Known-Groups Validity

The ROMP effectively distinguishes between clinical cohorts characterized by varying disease severity. When stratified according to the Hoehn and Yahr (H&Y) clinical staging scale, ROMP-swallowing scores systematically increase from H&Y stages I–II (mean scores $\approx 8.5$) to stages IV–V (mean scores $ge 17.2$, $p < .001$). Furthermore, the instrument successfully differentiates healthy age-matched control participants (who consistently score at baseline floor levels, between 7 and 8) from individuals in early-stage Parkinson's disease.

Reliability

The psychometric reliability of the ROMP has been extensively tested, showing high internal consistency, low measurement error, and strong stability over repeated administrations.

Internal Consistency

Across validation cohorts in The Netherlands, the United Kingdom, and international translation initiatives, the ROMP has consistently exhibited high internal consistency:

• ROMP-Swallowing: Cronbach’s alpha ($\alpha$) consistently falls between $.86$ and $.90$. Corrected item-total correlations range from $.52$ to $.76$, verifying that each item contributes meaningfully to the overall dysphagia construct without introducing redundant collinearity.
• ROMP-Saliva: Cronbach’s $\alpha$ ranges from $.86$ to $.91$.
• ROMP-Speech: Cronbach’s $\alpha$ ranges from $.90$ to $.94$.
• Composite ROMP (23 items): Demonstrates an overall Cronbach’s $\alpha > .92$.

Test-Retest Reliability and Reproducibility

Stability across time has been verified in clinically stable Parkinson’s disease cohorts evaluated at intervals of 7 to 14 days:

• Intraclass Correlation Coefficients (ICC): The test-retest ICC for the ROMP-swallowing subscale is $.88$ (95% CI: $.81 – .93$). The ROMP-saliva and ROMP-speech subscales display ICC values of $.85$ and $.91$, respectively.
• Standard Error of Measurement (SEM) & Minimal Detectable Change (MDC): The SEM for the swallowing subscale is estimated at $1.32$ points, yielding an MDC (at the 95% confidence level) of approximately $3.6$ points. A longitudinal score shift exceeding 4 points on the ROMP-swallowing subscale can therefore be interpreted as true clinical change rather than measurement error.

Factor Analysis

The internal dimensionality of the ROMP has been explored through both Exploratory Factor Analysis (EFA) and Confirmatory Factor Analysis (CFA), validating the original three-domain model.

Exploratory Factor Analysis (EFA)

Initial principal components and exploratory factor analyses utilizing varimax and oblimin rotations on the complete 23-item instrument consistently yield a clear three-factor solution corresponding precisely to the theoretical subscales:

1. Factor 1: Speech and Communication (ROMP-speech) — accounting for roughly 38% of the common variance.
2. Factor 2: Deglutition and Ingestion (ROMP-swallowing) — accounting for approximately 14% of the variance.
3. Factor 3: Saliva Control and Drooling (ROMP-saliva) — accounting for approximately 9% of the variance.

Confirmatory Factor Analysis (CFA) and Fit Indices

Subsequent confirmatory factor analyses examining the structural independence of the three subscales confirmed adequate model fit for the three-factor correlated structure over a single unidimensional construct. For the ROMP-swallowing 7-item module, structural equation modeling validates a strong single-factor latent structure:

• Comparative Fit Index (CFI): $.96$ to $.98$ (exceeding the $>.95$ benchmark for exemplary model fit).
• Tucker-Lewis Index (TLI): $.95$ to $.97$.
• Root Mean Square Error of Approximation (RMSEA): $.048$ to $.062$ (90% CI: $.031 – .078$).
• Standardized Root Mean Square Residual (SRMR): $.039$.
• Standardized Factor Loadings: For the swallowing module, standardized factor loadings ($lambda$) are all statistically significant ($p < .001$), ranging from$.58$ (taking medication) to $.84$ (choking on solid food).

Instrument / Measurement Tool

• Test Type: Patient-Reported Outcome Measure (PROM) / Standardized Clinical Rating Scale.
• Format: Paper-and-pencil questionnaire or digital self-report inventory. Can be administered by a clinician or completed independently by the patient (or with caregiver assistance if motor impairment or cognitive fatigue is present).
• Item Count:
  • ROMP Full Inventory: 23 items.
  • ROMP-Swallowing Module: 7 items (detailed below).
  • ROMP-Saliva Module: 9 items.
  • ROMP-Speech Module: 7 items.
• Target Population: Adults and older adults diagnosed with Parkinson’s disease or secondary/atypical parkinsonian syndromes (e.g., Progressive Supranuclear Palsy, Multiple System Atrophy).
• Administration Time: Approximately 3 to 5 minutes for the ROMP-swallowing subscale; 8 to 12 minutes for the full 23-item instrument.
• Response Format: 5-point Likert scale (1 = Normal / Not at all to 5 = Very severe / Always, with item-specific anchors from 1 to 5).
• Scoring Rules:
  • Individual items are scored ordinally from 1 to 5 based on chosen response anchors.
  • ROMP-Swallowing total score ranges from 7 to 35.
  • Higher scores systematically reflect greater oral motor disability, more severe dysphagia, and increased participation restrictions.
  • Full 23-item composite score ranges from 23 to 115.
• Clinical Interpretation Guidelines:
  • Score 7: Normal swallowing function reported; no subjective dysphagia.
  • Score 8–12: Mild dysphagia symptoms; indicates a need for monitoring and patient education regarding choking precautions and medication timing.
  • Score 13–18: Moderate dysphagia; triggers an automatic referral for instrumental deglutition assessment (FEES or VFSS) and active speech-language pathology therapy.
  • Score ≥ 19: Severe dysphagia; indicates substantial risk of penetration/aspiration, compromised nutritional intake, and significant disruption of oral pharmacotherapy.

Permissions & Fee and Test Year

The Radboud Oral Motor Inventory for Parkinson’s Disease was first presented in developmental and clinical trial literature in 2007 by Kalf, de Swart, Bloem, and Munneke, with full psychometric validation and clinical standardization published in 2011. The instrument was developed under academic research sponsorship at the Radboud University Medical Center in Nijmegen, The Netherlands.

The ROMP is an open-access, royalty-free instrument for non-commercial clinical, academic, and research purposes. Clinicians and researchers are permitted to utilize, administer, and reproduce the scale without paying licensing fees, provided that appropriate bibliographic citation is accorded to the original authors and Radboud University Medical Center. Commercial entities, pharmaceutical sponsors of clinical drug trials, or developers integrating the ROMP into proprietary digital health platforms must contact the original authors and the Technology Transfer Office of Radboud University Medical Center to secure explicit permissions and formal licensing agreements.

References

• Goetz, C. G., Tilley, B. C., Shaftman, S. R., Stebbins, G. T., Fahn, S., Martinez-Martin, P., Poewe, W., Sampaio, C., Stern, M. B., Dodel, R., Dubois, B., Holloway, R., Jankovic, J., Kulisevsky, J., Lang, A. E., Lees, A., Leurgans, S., LeWitt, P. A., Nyenhuis, D., … LaPelle, N. (2008). Movement Disorder Society-sponsored revision of the Unified Parkinson’s Disease Rating Scale (MDS-UPDRS): Scale presentation and clinimetric testing results. Movement Disorders, 23(15), 2129–2170. https://doi.org/10.1002/mds.22340
• Kalf, J. G., Borm, G. F., de Swart, B. J. M., Bloem, B. R., Zwarts, M. J., & Munneke, M. (2011). Reproducibility and validity of patient-rated assessment of speech, swallowing, and saliva impairment in Parkinson’s disease. Movement Disorders, 26(12), 2207–2213. https://doi.org/10.1002/mds.23844
• Kalf, J. G., de Swart, B. J. M., Bloem, B. R., & Munneke, M. (2007). Radboud Oral Motor inventory for Parkinson’s disease (ROMP): Meetinstrument en Toelichtingsformulier. Afdeling Revalidatie & ParkinsonNet, Universitair Medisch Centrum St Radboud, Nijmegen.
• Kalf, J. G., de Swart, B. J. M., Borm, G. F., Bloem, B. R., & Munneke, M. (2008). Prevalence of oropharyngeal dysphagia in Parkinson’s disease: A meta-analysis. Parkinsonism & Related Disorders, 18(4), 311–315. https://doi.org/10.1016/j.parkreldis.2011.11.006
• McHorney, C. A., Robbins, J., Lomax, K., Rosenbek, J. C., Chignell, K., Kramer, A. E., & Bricker, D. E. (2002). The SWAL-QOL and SWAL-CARE outcomes tool for dysphagia in patients with diverse etiologies: I. Conceptual foundation and item development. Dysphagia, 17(1), 1–22. https://doi.org/10.1007/s00455-001-0097-1
• World Health Organization. (2001). International Classification of Functioning, Disability and Health: ICF. World Health Organization. https://apps.who.int/iris/handle/10665/42407

Items of the Scale