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Every manufacturer's headline feature is a waveform. Here is what they actually mean.
The pattern of electrical energy a stimulator delivers is the single biggest technical difference between platforms. It determines whether you feel the stimulation, how quickly relief arrives, how much power the device consumes, and — with closed-loop systems — whether the device adjusts itself. This module explains each one without the marketing.
What You'll Learn
Approx. 12 min read- The four parameters that define any stimulation waveform
- What paresthesia is and why most modern therapies avoid it
- How tonic, burst, 10 kHz, DTM, multiphase and FAST differ
- What open-loop and closed-loop actually mean
- What an ECAP is and why it can be measured
- How waveform choice interacts with battery and recharging
The Building Blocks
Four parameters define every waveform
Once you understand these four dials, every named therapy on the market becomes a specific combination of settings rather than a mystery.
Amplitude
How strong each pulse is, measured in milliamps or volts. Raise it and more nerve fibres are recruited. Raise it too far and stimulation becomes uncomfortable.
Frequency
How many pulses per second, measured in hertz. Conventional stimulation runs in the tens of hertz; high-frequency therapy runs at 10,000. This is the parameter that most defines the named therapies.
Pulse width
How long each individual pulse lasts, measured in microseconds. It influences which fibres are preferentially activated and contributes to the character of the sensation.
Contact configuration
Which electrodes are active and in which polarity. This shapes where the electrical field goes, and it is the main tool for redirecting coverage without surgery.
The Central Concept
Paresthesia: the tingling, and why the field moved away from it
Paresthesia is the buzzing, tingling or vibrating sensation produced when stimulation activates large sensory fibres above the threshold of perception. For the first several decades of spinal cord stimulation it was considered essential: the paresthesia had to be mapped onto the painful area, and it was how you knew the therapy was working.
It also created problems. Some patients found the sensation unpleasant or intrusive. It changed with posture as the spinal cord shifted relative to the leads — comfortable when sitting, jolting when standing. And because it was the marker of therapy, it made blinded studies nearly impossible: everyone knew whether their device was on.
Sub-perception, or paresthesia-free, stimulation delivers therapy below the sensory threshold. Most modern waveforms — burst, 10 kHz, DTM, multiphase, FAST — are designed this way. You feel relief without feeling the device. It also made properly blinded trials possible for the first time.
The Waveforms
Each named therapy, in plain terms
The original — all manufacturers
Tonic stimulation
A steady, regular train of pulses, typically between about 40 and 100 Hz, delivered above the perception threshold so it produces paresthesia mapped onto the painful area.
- Longest track record of any waveform
- Produces tingling by design
- Intensity varies with body position
- Still useful, and still the studied option for some indications
Abbott
BurstDR
Instead of evenly spaced pulses, energy is delivered in tightly grouped clusters — bursts — separated by quiet periods, at a low overall dose and below the perception threshold.
- Paresthesia-free
- Supported by the SUNBURST crossover trial
- FlexBurst360 extends it across up to six pain areas
- Lower energy delivery than continuous high-output stimulation
Nevro / Globus
10 kHz high-frequency
Stimulation delivered at 10,000 Hz, far above the frequency at which paresthesia can be perceived. Because there is no sensation to map, lead placement is guided by anatomic landmarks rather than by patient feedback.
- Paresthesia-free by design
- Placed by anatomy, not by paresthesia mapping
- Randomized evidence in back and leg pain, PDN and non-surgical back pain
- Higher frequency has implications for charging
Medtronic
DTM — Differential Target Multiplexed
Multiple programs delivered in an interleaved pattern, developed from preclinical work suggesting that stimulation can influence glial cells as well as neurons in the dorsal horn.
- Multiplexed rather than single-pattern delivery
- Sub-perception
- Randomized evidence in chronic low back pain
- Available across Medtronic's generator range
Boston Scientific
FAST — Fast-Acting Sub-perception Therapy
A sub-perception waveform designed to produce relief quickly rather than requiring a long titration period, described by the manufacturer as acting through surround inhibition.
- Paresthesia-free
- Intended for rapid onset of relief
- Can be combined with other waveforms on the same device
- Multi-year follow-up data published
BIOTRONIK
RESONANCE multiphase
A charge-distributed pattern that varies stimulation across the array in both space and time, intended to activate the dorsal horn at lower power than conventional approaches.
- Delivered by the BioARC stimulation engine
- Charge distributed across contacts rather than repeated identically
- BENEFIT-02 reported majority preference over commercial SCS
- Paired with automatic daily remote monitoring
The Other Axis
Open loop versus closed loop
Waveform is what the device delivers. Open- versus closed-loop is how it decides how much to deliver — and it is an entirely separate question.
An open-loop system delivers exactly what it was programmed to deliver. It has no way of knowing what effect that had. This is how virtually all stimulators worked until recently, and most still do.
The problem open-loop has to live with is anatomical. Your spinal cord moves inside the spinal canal — with every breath, cough, and change of position. As it moves closer to or further from the leads, the same output produces a different amount of nerve activation. That is why some patients on paresthesia-based therapy find stimulation comfortable lying down and jolting when they stand.
A closed-loop system measures the result and corrects. After each pulse, it records the evoked compound action potential — the ECAP, the electrical signal the spinal cord produces in response — compares it against the target the physician set, and adjusts the next pulse accordingly. Saluda's Evoke adjusts more than a hundred times per second; Medtronic's Inceptiv senses roughly fifty times per second.
What an ECAP actually is
When a stimulation pulse activates nerve fibres in the dorsal columns, those fibres fire together and produce a small electrical signal that travels along the cord. The same electrodes that delivered the pulse can listen for it.
The size of that signal is a direct, objective measure of how much neural tissue was activated — the first time in the history of this field that a stimulator could know what it had actually done rather than only what it had attempted. It is worth being precise about what this does and does not mean: an ECAP measures neural activation, not pain. Pain remains subjective.
Quick Reference
The waveforms side by side
| Therapy | Manufacturer | Paresthesia | Distinguishing idea |
|---|---|---|---|
| Tonic | All | Yes, by design | The original approach; mapped coverage |
| BurstDR | Abbott | No | Clustered bursts at low dose; up to six areas |
| 10 kHz | Nevro / Globus | No | Frequency far above perception; anatomic placement |
| DTM | Medtronic | No | Interleaved multiplexed programs |
| FAST | Boston Scientific | No | Rapid-onset sub-perception; combinable |
| RESONANCE multiphase | BIOTRONIK | No | Charge distributed in space and time |
| Closed loop (ECAP) | Saluda, Medtronic | Varies | Measures the response and corrects each pulse |
Practical Consequences
What waveform choice actually changes for you
Whether you feel it
The most immediate difference. Some patients find paresthesia reassuring; many find it intrusive. Most modern options let you avoid it entirely.
Charging burden
Different waveforms consume different amounts of energy. This interacts directly with whether you need a rechargeable device and how often you would charge it.
Programming flexibility
Platforms that support several waveforms — or combinations of them — give more room to adjust if the first approach does not hold. That only helps if follow-up actually happens.
Common Questions
Questions about waveforms
Take the next step in understanding your options
Read how candidacy is assessed, then discuss your history and imaging with your own clinician. This site does not arrange evaluations.