On / Off: The Narrow Band of Coherence

In Parkinson’s disease, on and off are not metaphors. They are lived states.

For most patients, the words refer first to medication—especially Sinemet. On is when dopamine replacement is working: movement is smoother, tremor quieter, initiation less effortful. Off is when it is not: stiffness returns, tremor reasserts itself, and everything costs more. Patients learn this rhythm early. Days are planned around it. Meals are timed. Distances are judged by how long the on window might last.

I was told, early on, that I had drawn the best version of a bad lottery ticket. Tremor-predominant Parkinson’s, slower progression, fewer early cognitive effects, longer preservation of independence. It was too soon to know whether that would prove true, but it shaped expectations—about what decline might look like, how gradual it would be, and how manageable it might remain.

I watched friends whose Parkinson’s fit the medication on/off pattern cleanly. Their fluctuations were chemical, temporal, predictable enough to live with, if never comfortable.

Less than twenty-eight months after my diagnosis, during a research visit connected to my adaptive deep brain stimulation implantation, I encountered a different use of the same words—on and off—that referred to something else entirely.

This time, the switch had nothing to do with dopamine levels in my bloodstream. It was about regulation being present or absent inside the system itself. And by system, I mean me.

When the electrical stimulation was on, my body occupied a familiar, imperfect equilibrium. When it was turned off—briefly and intentionally—the tremor in my right forearm escaped its bounds. What had once caused my hand to flap at my side recruited the rest of my body. One oscillating component, no longer being held in check, began to drive the whole. My arm shook so violently that it shook my entire body with it.

This was not the familiar feeling of being off medication. It was not stiffness or slowness or effort. It was something deeper.

It was the loss of arbitration.

One part overwhelmed the whole.

The language was the same—on and off—but the layer was deeper. Medication, for others, always helped restore capacity. What I saw now, in me, was the presence or absence of a governing process that kept the system coherent at all.

That moment changed how my Parkinson’s looks to me. And it changed how I understand what modern treatment is actually doing for me.

Compensation Is Not Regulation

Parkinson’s teaches its people to become skilled compensators.

Long before movement visibly fails, the body recruits workarounds. Muscles co-contract to stabilize joints. Attention substitutes for automaticity. Movements slow, segment, rehearse. Actions that once happened on their own now require thought. From the outside, this often looks like resilience. From the inside, it feels like rising cost.

Compensation keeps parts functioning. Regulation keeps parts coordinated.

That distinction is easy to miss because compensation can work remarkably well for a long time. In tremor-predominant Parkinson’s especially, I am told, people may remain upright, articulate, cognitively intact, and socially engaged for years beyond diagnosis. The visible markers of disability arrive late. The internal labor does not.

What compensation cannot do is prevent coupling.

Every complex system contains oscillators—components that naturally fluctuate. In a healthy system, those oscillations are damped, timed, and kept from entraining one another. Regulation performs that work quietly. It does not eliminate variability; it keeps variability from running away.

When regulation weakens, oscillations begin to leak across boundaries.

In Parkinson’s, tremor is one such oscillator. As long as it remains locally contained, it is disruptive but survivable. When the mechanisms that limit its spread falter, the tremor no longer belongs to one limb. It becomes a driver. Other subsystems fall into step with it. The system stops negotiating and starts echoing.

I think this is why the moment with stimulation turned off felt so different from what is said about being off medication. Dopaminergic “off” states reduce available capacity. They make movement harder, slower, more effortful. But effort still counts. The system remains arbitrated, even if underpowered.

What disappeared when stimulation was turned off was not strength or smoothness. It was governance.

Deep brain stimulation does not ask the system to work harder. It listens for instability and intervenes to keep oscillations from recruiting one another. It is not restoring normal signaling. It is enforcing boundaries.

That distinction matters because compensation can mask the loss of regulation almost indefinitely—until it cannot. When the boundary finally gives way, the change is abrupt. The system does not gradually worsen. It reorganizes around its most dominant oscillation.

From the outside, this can look like sudden deterioration. From the inside, it feels like falling off a ledge that had been quietly narrowing for years.

I was flooded with gratitude for science, because my body suddenly understood that without what it was doing for me—moment by moment—life itself would not be bearable.

Nothing heroic is happening here. Something far rarer is.

Regulation Is Not Control

It is tempting to describe technologies like adaptive deep brain stimulation as forms of control. Electrodes are implanted. Signals are delivered. Parameters are tuned. Something external appears to be taking charge.

But control is not what is happening.

Control imposes outcomes. Regulation preserves relationships.

A controlling system dictates what a component must do. A regulatory system monitors behavior and intervenes only when deviation threatens coherence. It does not command the system toward a target state; it keeps the system from tearing itself apart.

Adaptive deep brain stimulation does not tell the brain how to move. It does not replace lost dopaminergic signaling with a synthetic equivalent. Instead, it listens for patterns that signal instability—neural signatures associated with oscillations escaping their bounds—and responds just enough to dampen them. The goal is not normality. The goal is containment.

That containment is dynamic. It adjusts moment by moment as internal conditions change. In systems terms, it functions as an externalized regulatory loop compensating for one the body can no longer sustain reliably.*

This is why turning the system off produces such an abrupt shift. When regulation fails, control cannot substitute for it. No amount of conscious effort, willpower, or strength can arbitrate competing oscillations once the referee is gone. The system does not need more instruction; it needs restraint.

Parkinson’s makes this distinction visible because so much function remains intact for so long. Speech persists. Cognition remains. Social presence continues. Observers assume that what remains is what matters.

But the work of regulation is invisible.

When it disappears, the change is not dramatic in a cinematic sense. It is matter-of-fact. The system follows the strongest signal available.

Seen this way, aDBS and DBS are not extraordinary because they are high-tech. The technology is extraordinary because it acknowledges a limit. It accepts that the system cannot self-regulate and builds scaffolding instead of pretending otherwise.

That is not control. It is humility, engineered.

And it is here that my respect for science quietly deepened—not because it promised restoration, but because it refused to overreach. It would also allow me to not seek an early end of life.

Prediction Failure Inside the Body

Movement is not reaction. It is anticipation.

In a healthy nervous system, action is guided less by feedback than by prediction. The brain continuously forecasts what the body is about to do, compares that expectation to incoming signals, and corrects only the difference. This is why movement usually feels smooth, timely, and largely effortless. The system is not waiting to see what happens; it is acting ahead of time.

Parkinson’s disrupts this machinery.

The loss is not simply chemical. It is temporal. Signals arrive late. Corrections lag. What should be continuous becomes segmented. The body no longer trusts its own forecasts, so it compensates by slowing down, by paying attention, by breaking fluid actions into conscious steps.

This is why Parkinson’s patients often say that everything costs more—even when they are still moving.

Tasks that depend on timing reveal this most clearly. Turning while walking. Starting and stopping. Carrying a half-full glass. The problem is not weakness. It is that prediction has narrowed. The system can no longer confidently simulate the near future, so it clings to the present moment and overcorrects.

Adaptive deep brain stimulation intersects this problem indirectly but decisively. By damping runaway oscillations, it stabilizes the temporal environment in which prediction occurs. It does not restore healthy forecasting. It makes forecasting usable again.

When regulation holds, even imperfect predictions can be corrected smoothly. When regulation is removed, prediction collapses entirely. The body stops anticipating and starts reacting. Timing dissolves. Tremor ceases to be a fluctuation and becomes a driver.

This is why the off state observed in the research setting felt so different from ordinary medication “off” periods, according to friends with PD. Dopamine depletion degrades prediction gradually. Loss of regulation breaks it outright.

The result is not just worse movement, but a different relationship to time. Actions feel rushed and delayed at once. Effort remains, but leverage disappears.

Living inside Parkinson’s means living inside this narrowing temporal margin. And seeing, firsthand, how a technology can stabilize time itself—not by fixing the brain, but by restraining its noise—quietly changed how I think about what science actually does.

Dissolution Without Collapse

Collapse is loud. Dissolution is quiet.

Most people imagine system failure as a sudden event—a break, a crash, a clear before and after. Parkinson’s does not work that way. It dismantles coherence while leaving components intact. Signals still fire. Muscles still contract. From the outside, the system appears operational.

What is dissolving is not capacity, but integration.

This is why Parkinson’s can progress for years without triggering alarm, because notice has not yet been triggered. The system does not stop. It sheds slack. Margins narrow. Timing tightens. Compensation fills the gaps left by regulation. Each adjustment works—until the cumulative loss of coherence crosses a threshold.

That threshold is not announced. It is revealed.

The brief removal of my deep brain stimulation’s electrical impulse to my brain did not cause collapse. Nothing broke. No new damage occurred. Instead, it exposed how much of the system’s apparent stability depended on active containment. Once that containment was gone, the system reorganized around its most dominant oscillation. Tremor did not worsen; it took over.

This is dissolution without collapse.

The phrase matters because it explains why Parkinson’s is so often misunderstood. Observers look for failure in the wrong places. They expect absence—of movement, of speech, of participation. What they miss is the loss of coordination among things that are still present.

Seen clearly, this is also where my sense of awe sharpened.

What science was doing here was not reversing decline. It was preventing disintegration. It was holding relationships together that the body could no longer reliably maintain on its own. Success looked like nothing happening. Stability was an achievement, not a baseline.

Living inside that reality reframed treatment entirely. Medicine was no longer merely alleviating symptoms. It was standing watch at the edge of coherence.

That is quieter than cure. And far more impressive.

The Narrow Band, Held

Living with Parkinson’s means living inside a narrow band of coherence that no longer sustains itself. Nothing about that band is guaranteed. It exists only because countless people—scientists, clinicians, engineers, trial participants—spent decades learning how to intervene without overruling, how to stabilize without pretending to restore what cannot yet be restored.

That realization changed my relationship to science.

I have always trusted it. I have always believed in it. As a lifelong atheist and a Jew formed by argument, evidence, and inquiry, science was never something I needed to be persuaded into. It was where truth lived. What changed was not belief, but appreciation.

What I see now is not just knowledge, but restraint. Not conquest, but care. Not answers, but vigilance.

Deep brain stimulation does not fix my brain. It intervenes to stop the tremor. As it works, nothing visibly dramatic happens. My arm does not stop being mine. My intentions still feel like intentions. Life continues, not restored, but held.

That is the wonder.

Science, at its best, does not promise salvation. It does something quieter and harder. It keeps fragile systems from unraveling while admitting how close they already are to doing so. It builds scaffolding where self-regulation fails and stands watch where collapse would otherwise arrive unnoticed.

Knowing that—feeling it in my own body—has changed how I move through the world. Gratitude is no longer abstract. Responsibility is no longer optional. Attention feels earned.

The band is narrow. The work that holds it is precise. And the fact that it exists at all is not something I take for granted anymore.

* (Upon seeing the severity my tremor had increased to since the implantation, my doctor advised that it appeared that my particular version of tremor-predominant PD likely meant the “adaptive” feature of my aDBS system would never have to be turned on. For me, a constant level of electricity would likely always be needed for control of my tremor. Rather than electricity in an amount that would increase and decrease, according to the dictates of my brain communicating with the pulse generator to modulate the level of electrical impulse from time to time. So for me, the further wonder of modern science, adding the “a” to DBS, has, so far, turned out not to be necessary.

© 2026 Michael A. Pink. All rights reserved.