Dysphonia Severity Index (DSI) Calculator – Definition and Formula
Dysphonia Severity Index (DSI) Calculator – Definition and Formula: Discover the Calculator with Definition, Formula, Step-by-Step guide, and Interpretation for Dysphonia or Other Voice Disorders Assessment.
Dysphonia Severity Index (DSI) Definition
The Dysphonia Severity Index (DSI) is an objective, multiparametric score that quantifies voice impairment severity on a continuous scale. Invented by Dejonckere et al. (1996), it integrates aerodynamic, acoustic, and temporal measures to capture subtle changes in vocal function.
Its primary purpose is to:
• Standardize voice assessment across practitioners and clinics.
• Track changes over time—for instance, pre- and post-therapy or surgery.
• Facilitate research by providing a numeric outcome measure.
Dysphonia Severity Index (DSI) Calculator
Our online DSI Calculator streamlines data entry and reduces calculation errors. Rather than plugging numbers into a spreadsheet or doing mental math, you’ll enter four vocal parameters into a clear interface. Within milliseconds, the DSI appears alongside interpretation guidance—no manual lookup tables required.
Step-by-Step Guide to use DSI Calculator
Clinic Information
- Institution Name: Tag your results to a hospital, university clinic, or private practice.
- Clinician Name & Designation: Build traceability for readers to know who’s behind the data.
- Contact: Optional, for follow-up or audit trails.
Patient Information
- Name, Age, Gender, Mobile, Address: Demographics for record keeping and subgroup analysis.
- Date of Assessment: Defaults to today’s date; change if you’re logging past data.
- Chief Complaint: Free text—capture patient-reported symptoms.
DSI Measurements
- Maximum Phonation Time (MPT in seconds): Ask the patient to sustain /a/ at comfortable pitch and loudness—the longest of three trials.
- Highest Frequency (F0-High in Hz): Measure via pitch glissando from modal to highest phonable pitch.
- Lowest Intensity (I-Low in dB): Instruct the patient to phonate /a/ at their quietest detectable level.
- Jitter (%): Acoustic perturbation measured by your software (e.g., Praat, MDVP).
Action Buttons
- Reset: Clears all fields for next patient.
- Calculate DSI: Runs the formula and displays a numeric score.
Dysphonia Severity Index (DSI) Formula
The DSI calculation uses a weighted sum of four parameters:
DSI = 0.13 × MPT + 0.0053 × F0-High − 0.26 × I-Low − 1.18 × Jitter (%) + 12.4
Where:
- MPT = Maximum Phonation Time (seconds)
- F0-High = Highest fundamental frequency (Hz)
- I-Low = Lowest intensity (dB)
- Jitter = Cycle-to-cycle frequency variability (%)
Step-by-Step Calculation Example
Suppose a 45-year-old teacher presents with hoarseness. You measure:
- MPT = 12.5 s
- F0-High = 500 Hz
- I-Low = 45 dB
- Jitter = 1.2%
Plugging into the formula:
- 0.13 × MPT = 0.13 × 12.5 = 1.625
- 0.0053 × F0-High = 0.0053 × 500 = 2.65
- 0.26 × I-Low = 0.26 × 45 = 11.7
- 1.18 × Jitter = 1.18 × 1.2 = 1.416
DSI = 1.625 + 2.65 – 11.7 – 1.416 + 12.4 = 3.559
A score of 3.56 suggests mild dysphonia (refer to Interpretation table).
Dysphonia Severity Index (DSI) Interpretation
Use the following table to convert DSI scores into clinical dysphonia categories.
| Impairment Group Level | DSI Range | Description |
| 0 | < −2.0 | Severe persisting aphonia: patient has no voice, is unable to phonate |
| 1 | −1.9 to +0.3 | Constant dysphonia: sporadic periods of phonation, aphonic periods may be present |
| 2 | +0.4 to +2.2 | Moderate dysphonia: the patient can produce voice, but there are frequent periods of dysphonia |
| 3 | +2.3 to +3.3 | Slight to moderate dysphonia: less frequent periods of disturbed phonation or slight persisting dysphonia |
| 4 | +3.4 to +4.3 | Slight dysphonia: sporadic dysphonic moments for short periods |
| 5 | > +4.4 | No dysphonia |
Clinical Application of Dysphonia Severity Index (DSI)
- Tracking Progress: A patient post-microlaryngoscopic surgery improves from level 2 to level 4 over eight weeks—objective proof of therapy efficacy.
- Research: Compare DSI changes between two rehabilitation protocols.
- Patient Counseling: Visualizing DSI improvement can boost adherence—patients see concrete data, not just subjective impressions.
Frequently Asked Questions
What is Dysphonia Severity Index (DSI)?
The Dysphonia Severity Index (DSI) is an objective, multiparametric score that quantifies voice impairment severity on a continuous scale.
How does the Dysphonia Severity Index (DSI) Calculator work for beginners?
The DSI Calculator takes four simple voice measurements MPT, F0-High, I-Low, and jitter and applies a proven formula to yield a score that reflects vocal health. It’s user-friendly: just input values and click “Calculate.” No background in statistics needed.
What equipment do I need to measure parameters for DSI?
You’ll need a reliable microphone, calibrated sound level meter or software to record dB SPL, and a pitch analysis tool (like Praat). A stopwatch or digital timer measures MPT.
Can patients with neurological voice disorders use the DSI?
Yes, Studies show DSI reliably tracks vocal impairment in Parkinson’s disease, essential tremor, and other neurological conditions (Sapir et al., 2001).
Can I interpret DSI without a calculator?
Technically yes, but manual calculation increases the risk of arithmetic errors. The web-based tool cuts down on miscalculations and saves time.
Are there limitations to the DSI?
DSI assumes patient cooperation and accurate parameter measurement. Severe tremor can inflate jitter values, and background noise can affect I-Low. Use in conjunction with perceptual scales.
How does DSI compare to the GRBAS scale?
GRBAS is perceptual and subjective—dependent on rater experience. DSI offers an objective, reproducible metric. Combining both provides a comprehensive assessment.
What our Users are Saying
This DSI Calculator has completely streamlined our voice assessments. It’s accurate, user-friendly, and perfect for busy clinics. A must-have tool for any speech-language pathologist working with dysphonia.
I was impressed by the clarity of the interface. The DSI calculator results are reliable, and the interpretation section helps even new clinicians understand what each score means instantly.
Finally, a DSI calculator that’s both practical and research-aligned. The integration of patient demographics with acoustic data supports comprehensive documentation and enhances therapy planning
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