Parkinson's Disease Rating Scales: Hoehn & Yahr, MDS-UPDRS, and More

Rating scales are standardized tools that doctors, researchers, and clinical trial teams use to measure the severity of Parkinson's disease, track changes over time, and evaluate whether treatments are working. If you have Parkinson's, your neurologist likely uses one or more of these scales during your visits. Understanding what these scales measure and what your scores mean can help you participate more actively in your own care and better interpret clinical trial results.

Hoehn and Yahr Scale

The Hoehn and Yahr (H&Y) scale is the oldest and most widely recognized staging system for Parkinson's disease. First published in 1967 by neurologists Margaret Hoehn and Melvin Yahr, it classifies PD into five stages based on the degree of motor disability and whether symptoms are on one or both sides of the body.

Original Five-Stage Scale

Strengths and Limitations

The Hoehn and Yahr scale's greatest strength is its simplicity. A single number communicates the general severity of disease in a way that is immediately understood by clinicians, researchers, patients, and families. It is used worldwide and is required in virtually all clinical trial protocols as a basic descriptor of the study population.

However, the scale has significant limitations that a 2004 Movement Disorder Society task force report highlighted:

• It focuses almost entirely on motor symptoms. Non-motor symptoms — cognitive impairment, depression, sleep disorders, autonomic dysfunction, and pain — are not captured, despite having a major impact on quality of life and disability.
• The stages are not evenly spaced. The jump from Stage 2 to Stage 3 (the onset of postural instability) represents a much larger functional change than the jump from Stage 1 to Stage 2.
• It does not capture treatment response. Two patients at the same H&Y stage may have very different functional abilities depending on their medication response.
• It does not distinguish subtypes. A tremor-dominant patient at Stage 2 may have a very different prognosis from a PIGD (postural instability/gait difficulty) patient at Stage 2.

Despite these limitations, the H&Y scale remains indispensable as a quick-reference staging tool and is unlikely to be replaced in clinical practice. Most detailed assessments use it alongside more comprehensive scales.

MDS-UPDRS (Movement Disorder Society-Unified Parkinson's Disease Rating Scale)

The MDS-UPDRS is the most comprehensive standardized assessment tool for Parkinson's disease. It is the gold standard in clinical trials and is widely used in specialty clinical care. The current version, sponsored by the Movement Disorder Society and published in 2008 by Goetz and colleagues in Movement Disorders, is a major revision of the original UPDRS developed in the 1980s.

The Four Parts of the MDS-UPDRS

The MDS-UPDRS is divided into four parts, each assessing a different aspect of the disease. Together, they provide a comprehensive picture of disease severity:

Part I: Non-Motor Experiences of Daily Living (13 items)

This section evaluates the impact of non-motor symptoms on daily life. It covers cognitive impairment, hallucinations, depressed mood, anxious mood, apathy, features of dopamine dysregulation syndrome, sleep problems, daytime sleepiness, pain, urinary problems, constipation, lightheadedness on standing, and fatigue.

Part I is particularly valuable because it captures symptoms that the Hoehn and Yahr scale completely misses. Patients rate each item from 0 (normal) to 4 (severe), either during the clinic visit or on a questionnaire completed beforehand. The maximum score is 52.

Part II: Motor Experiences of Daily Living (13 items)

This section asks about motor-related activities of daily living: speech, saliva and drooling, chewing and swallowing, eating tasks, dressing, hygiene, handwriting, doing hobbies, turning in bed, tremor, getting out of bed or a car, walking and balance, and freezing. Patients rate each from 0 to 4. Maximum score: 52.

Part III: Motor Examination (33 scored items across 18 categories)

This is the most detailed section and is performed by the clinician during the office visit. It involves direct observation and testing of:

• Speech
• Facial expression
• Rigidity (tested at neck and all four limbs)
• Finger tapping, hand movements, and pronation-supination
• Toe tapping and leg agility
• Arising from a chair
• Gait
• Freezing of gait
• Postural stability (the “pull test”)
• Posture
• Body bradykinesia
• Postural tremor and kinetic tremor of hands
• Rest tremor amplitude (hands, feet, jaw)
• Constancy of rest tremor

Each item is scored 0-4. The maximum Part III score is 132. This section is performed twice in many clinical trials: once while the patient is “on” their medication (during a period of good symptom control) and once while “off” (after medication has been withheld). The difference between on and off scores reflects the degree of levodopa responsiveness.

Part IV: Motor Complications (6 items)

This section evaluates the complications that develop with long-term levodopa therapy: time spent with dyskinesia, functional impact of dyskinesia, time spent in the “off” state, functional impact of motor fluctuations, complexity of motor fluctuations, and painful “off” dystonia. Maximum score: 24.

What MDS-UPDRS Scores Mean

Total MDS-UPDRS scores can range from 0 to 260. In clinical trials, changes in the total score or in specific Part scores (especially Part III) are used to determine whether a treatment is effective. Here are approximate ranges for Part III (motor examination) scores:

A clinically meaningful change on Part III is generally considered to be 3-5 points or greater. In clinical trials, treatments that reduce the Part III score by 5 or more points compared to placebo are typically regarded as having meaningful motor benefit.

Schwab and England Activities of Daily Living Scale

The Schwab and England (S&E) scale, first published in 1969, measures overall functional ability on a single percentage scale from 100% (completely independent) to 0% (bedridden with no vegetative function). It is frequently used alongside the H&Y and MDS-UPDRS scales to provide a quick summary of functional status.

The S&E scale is simple but effective for communicating functional status in a single number. It is routinely used in clinical practice and as an inclusion/exclusion criterion in clinical trials (for example, requiring an S&E score of 70% or above for trial eligibility).

Non-Motor Symptom Scales

As understanding of Parkinson's as a multisystem disease has grown, several scales have been developed specifically to assess non-motor symptoms:

Non-Motor Symptoms Questionnaire (NMSQuest)

The NMSQuest, developed by Chaudhuri and colleagues and published in Movement Disorders (2006), is a 30-item self-completed screening questionnaire. Patients answer yes or no to questions about a range of non-motor symptoms including cardiovascular problems, sleep disorders, mood changes, perceptual issues (hallucinations), cognitive difficulties, gastrointestinal symptoms, urinary symptoms, sexual dysfunction, and pain. It is designed as a rapid screening tool rather than a severity measure.

Non-Motor Symptoms Scale (NMSS)

The NMSS (Martinez-Martin et al., Neurology, 2009) is a more detailed clinician-rated assessment of non-motor symptom severity and frequency across nine domains: cardiovascular, sleep/fatigue, mood/cognition, perceptual problems, attention/ memory, gastrointestinal tract, urinary function, sexual function, and miscellaneous (pain, taste/smell, weight change). Each item is scored for both severity (0-3) and frequency (1-4), providing a weighted severity score. The maximum total score is 360.

Parkinson's Disease Sleep Scale (PDSS)

The PDSS (Chaudhuri et al., 2002) is a 15-item visual analogue scale that evaluates sleep disturbances specific to PD, including overall quality of sleep, sleep onset insomnia, nocturnal restlessness, nighttime psychosis, nocturia, daytime somnolence, sleep apnea, and REM sleep behavior disorder. It is particularly useful for monitoring sleep-related treatment effects.

Quality of Life Measures

PDQ-39 (Parkinson's Disease Questionnaire-39)

The PDQ-39 is the most widely used PD-specific quality of life questionnaire. Developed by Peto and colleagues and published in Quality of Life Research (1995), it consists of 39 questions across eight dimensions: mobility, activities of daily living, emotional well-being, stigma, social support, cognition, communication, and bodily discomfort. Patients rate how often they have experienced each problem in the past month (never, occasionally, sometimes, often, always).

The PDQ-39 Summary Index (PDQ-39 SI) provides an overall quality of life score from 0 (no impact) to 100 (maximum impact). Lower scores indicate better quality of life. The PDQ-39 is valued in clinical trials because it captures the patient's own perspective on how PD affects their daily life, which may differ substantially from clinician-rated motor scores.

PDQ-8 (Short Form)

The PDQ-8 is an abbreviated version of the PDQ-39 containing eight questions (one from each dimension). It provides a rapid quality-of-life assessment and correlates well with the full 39-item version. It is useful when time is limited or when frequent repeated assessments are needed.

How Rating Scales Are Used in Clinical Practice

During a typical neurology visit for Parkinson's disease, your doctor may use these scales in several ways:

• Baseline assessment. At diagnosis, your doctor establishes baseline scores that will be compared to future assessments to track disease progression.
• Treatment monitoring. Changes in your MDS-UPDRS Part III score before and after starting or adjusting medication help your doctor evaluate how well treatments are working.
• DBS programming. For patients with deep brain stimulation, Part III scores in different stimulation settings help optimize device programming.
• Clinical trial eligibility. Most clinical trials have specific score ranges as inclusion criteria (e.g., H&Y Stage 1-3, MDS-UPDRS Part III score between 20-50, S&E score 70% or above).
• Disability determination. Some insurance and disability evaluations reference H&Y stage and S&E scores.

Tips for Patients: Getting the Most Accurate Assessment

The accuracy of your rating scale scores depends on several factors. Here are practical tips:

• Be consistent about medication timing. Your motor scores can change dramatically depending on whether you are assessed during an “on” or “off” period. If your doctor asks you to come in “off” medication (having skipped your morning dose), follow those instructions carefully so the results are meaningful.
• Be honest about your function. Some patients tend to minimize their difficulties, while others may exaggerate them. Accurate self-reporting on Parts I and II of the MDS-UPDRS gives your doctor the best information to guide treatment.
• Keep a symptom diary. Tracking your “on” and “off” times, sleep quality, mood, and daily function between visits provides valuable context that a single in-office assessment cannot capture.
• Ask about your scores. You have every right to know your H&Y stage, MDS-UPDRS scores, and how they have changed over time. This information helps you understand your disease trajectory and participate in treatment decisions.
• Bring your care partner. A spouse, family member, or friend who observes you daily can often provide information that complements your own report, particularly regarding sleep disturbances, cognitive changes, and functional abilities that you may not fully appreciate.

Looking Ahead: Digital and Remote Assessment

The field of Parkinson's disease assessment is evolving. Wearable sensors, smartphone applications, and digital biomarkers are being developed to provide continuous, objective monitoring of motor symptoms like tremor, gait, and bradykinesia outside the clinic. These technologies have the potential to complement traditional rating scales by capturing day-to-day symptom fluctuations that a single office visit cannot detect.

Clinical trials are increasingly incorporating digital outcomes alongside traditional scales, and some movement disorder practices are experimenting with remote video-based assessments of the MDS-UPDRS Part III. While these approaches are not yet standard of care, they represent a promising direction for more personalized and continuous monitoring of disease progression.