Low-energy shockwaves:
According to studies – New treatment option for Alzheimer’s dementia and much more.
Shock waves in medicine – even the first idea had to do with the brain.
Thanks to intensive research, shock wave therapies have made great progress in the past decades, which has greatly expanded the possible applications of this form of therapy. In the beginning, only kidney stones were smashed, but a little later, bone fractures, calcifications of the shoulder, heel spurs and tendons or their attachments also began to be treated. Shock waves are now even used for coronary artery disease, wound healing and bone infections, and researchers are investigating the stimulating effect of shock waves on stem cells, heart muscle cells and nerve cells.
The first patent for a focused shock wave to treat brain tumours was granted as early as 1951. But although the idea was a good one, it could not be realised in the form envisaged at the time until today. Instead, the company Dornier (once an aircraft manufacturer, which later became today’s Airbus; in medical technology, it is now known as Dornier MedTech Europe) developed the first so-called “lithotripter” (from the Greek “lithotripter”). lithos = Stone, tripsie = fragmentation), which had to wait until 1980 before it was approved for the treatment of kidney and bladder stones. Also in 1980, the world’s first kidney stone disintegrator was then used in Munich’s Großhadern Hospital. Despite initial scorn from many professional colleagues and a hefty price tag of 4.5 million Deutschmarks at the time, this marked the beginning of the triumphant advance of shock wave therapy. In the meantime, more than 5,000 lithotripters are in use, with which more than one million patients are treated annually and the treatment is a standard – just as in orthopaedics.
The areas of application in urology (e.g. erectile dysfunction) and in cardiology (e.g. angina pectoris), on the other hand, are generally still little known and are used for the regenerative treatment of neurodegenerative diseases such as Alzheimer’s dementia, other forms of dementia and other diseases that can potentially be treated with shock waves, such as Parkinson’s disease, condition after stroke, aphasia and many more. Unfortunately, there is still the greatest ignorance imaginable. So what exactly are shock waves, how do they work and how do they affect the human organism? We also want to answer these questions with regard to Transcranial Pulse Stimulation (TPS) in a brief overview.
On the road to success in medicine: shock waves can be used in a versatile and targeted way
Shock waves are first of all sound waves and not ultrasonic waves, as we will explain later. Shock waves are initially quite simply mechanical-acoustic pressure pulses. We all know this from our own experience when an aircraft breaks the sound barrier up in the sky and a very loud, extremely short bang is heard. Sound propagates in wave form around its source. Its speed depends on the nature of the environment and the respective temperature. At a temperature of 20 degrees Celsius, for example, it is 333 metres per second.
To generate sound waves, i.e. shock waves, the physical principle of electromagnetic induction is used. One can compare this with the sound generation in a loudspeaker: In this, a coil and a diaphragm are designed to produce short but powerful pulses. If you activate the current flow, electromagnetic fields form around the turns of the coil, which act through an insulating layer into the membrane. The rapid increase in current induces eddy currents in the membrane that diametrically oppose the original magnetic field. This creates repulsive forces that push the membrane away from the coil and create a pulse wave. This then spreads via a transmission medium (e.g. water or air).
For the disintegration of kidney stones (extracorporeal shock wave lithotripsy – ESWL), for example, shock wave signals are used with a positive pressure pulse of up to 2 µs (microseconds) duration and 10 – 100 MPa (100 – 1000 bar) pressure amplitude followed by a negative pressure pulse (tensile wave) of up to minus 10 MPa (- 10 bar) pressure and up to 4 µs duration. These are extremely high energies of over 3 mJ/mm2, (millijoules per square millimetre), which penetrate skin and elastic tissue such as muscles without damage, and only shatter solid resistance, in this case the stones.
In orthopaedics, focused shock wave therapies, EWST for short, are mainly used. Their energetic power is below that of lithotripsy in the medium-energy range up to a maximum of 1 mJ/mm2, as no solid objects are to be eliminated here, but rather tissue and bone structures are stimulated in a targeted manner, which can lead to a variety of healing processes through increased blood circulation and intensified metabolism, among other things. They are applied in narrow (focussed) target areas of the organism, so that the effect remains almost exclusively limited to the part of the body or area to be treated and surrounding tissue and organs are only marginally infiltrated. In pain therapy, focused shock waves are used to treat local pain points and deeper trigger points that cause pain. Trigger shock wave therapy is of particular importance here, as it differs once again from conventional shock wave therapies. (see also: www.schmerzinstitut.de/triggerpunkte/ )
Finally, Transcranial Pulse Stimulation (TPS) uses only low-energy shock waves that reach a maximum energy output of 0.25 mJ/mm2. These energies are so low that there is no tissue heating in the brain and the action potential of the shock waves is purely activating and regenerating. Incidentally, action potential, or AP for short, is the term used to describe the briefly sustained change in the membrane potential across the cell membrane. It serves to transmit stimuli via axons to other excitable cells such as neurons.
Shockwaves or ultrasound? Transcranial Pulse Stimulation (TPS) is a shock wave therapy.
In connection with Transcranial Pulse Stimulation (TPS), it is sometimes mistakenly referred to as ultrasound therapy. That is not correct. Transcranial Pulse Stimulation (TPS) is a shock wave therapy that can also be called sound wave therapy – and perhaps this is where the misunderstanding of calling TPS ultrasound therapy comes from.
This is because ultrasound, which is used in medicine primarily for diagnostic purposes to obtain information and therapeutically to relieve pain, among other things, is also a sound wave, but it moves in a frequency range of more than 20.000 Hz (Hertz) and has a significantly lower pressure amplitude than a shock wave. Ultrasound acts in periodic oscillations with a narrow bandwidth.
In contrast, shock waves are characterised by a single, predominantly positive pressure pulse followed by a comparatively small negative tensile pulse. This pulse ranges in frequency from a few kHz (kilohertz) to more than 10 MHz (megahertz). To put it simply, the frequency bands of ultrasound and shock waves are “miles apart”, so to speak, and each of these electromagnetic waves has very different properties, effects and thus possible tasks – also in medicine. Conclusion: Shock waves and ultrasound waves are related but not identical and Transcranial Pulse Stimulation (TPS) is a shock wave therapy.
Shock waves – five key mechanisms that have been scientifically researched
There are now numerous basic scientific studies on the function and effect of shock waves in medicine. In a meta-analysis published in 2022 (source: Wikipedia), the authors identified five key mechanisms:
- A stimulating effect on differentiated cells and progenitor/stem cells in cartilage and bone pathologies as well as a targeted inhibition of osteoclasts.
- A reduction in the concentration of substance P, which serves as a neurotransmitter in pain transmission via C-nerve fibres and in the neurogenic inflammatory circuit.
- A transient destruction of acetylcholine receptors at the muscular end plate, which reduces muscular overexcitation in trigger points, spasticity or muscular imbalances.
- A reduction in neuronal pain transmission and, if necessary, a reduction in pain transmission. An Activation of gate control mechanisms in the spinal cord
- A Stimulation of microcirculation, lymphatic drainage and the expression of lubricin, which serves as a lubricant for myofascia and tendons.
Shock waves in Alzheimer’s research: promising research data expanding.
Especially in research on Transcranial Pulse Stimulation (TPS), the following functions and effects are already considered proven or are currently being intensively investigated in numerous other extensive clinical studies in different approaches or modes of implementation (also placebo-controlled):
- through mechanotransduction, shock waves produce biological effects such as increasing cell permeability;
- there is a change in the concentration of neurotransmitters (increase serotonin and dopamine, decrease GABA) and neurotrophic growth factors (increase VEGF, BDNF and GDNF);
- Furthermore, nitric oxide (NO) is also released, which leads to direct vasodilation and thus to an increase in blood flow. In addition, a regulatory disturbance of the nitric oxide concentration is likely to be involved in neurodegenerative or neuroregenerative processes;
- Increase in the concentration of the growth factor BDNF (Brain-Derived Neurotrophic Factor). This plays a major role in the development and maturation, but also in the regeneration of nerve cells as well as in neuroneogenesis and neuroplasticity in the brain;
- Furthermore, a correlation of low BDNF concentrations in the brain and neuropsychiatric diseases such as Alzheimer’s disease, bipolar affective disorder and also schizophrenia could be shown.
The proof that shock waves lead to an upregulation of neuroplastic processes was provided by the fact that after stimulation of the sensory cortex, structural and functional coupling within the somatosensory cortex could still be demonstrated after one week. In addition, a reduction in cortical atrophy was demonstrated in patients with Alzheimer’s dementia.
Shock waves – a new chapter in medicine?
With all restraint, one could certainly postulate that shock waves or numerous other therapies based on electromagnetism can play a cardinal role in future medicine. Their various mechanisms of action are now well established, although it should be noted that different, presumably cumulative, mechanisms are responsible for the clinical effects and that many years of intensive research worldwide will be needed before all their parameters and interactions are understood in detail.
However, there is already a great advantage to be noted today: The side effects and after-effects of the use of shock waves are, if at all, only marginal and narrowly limited in time or ultimately negligible. While drugs can always have maximum side effects in addition to the intended effects, which often leads to patients having to take drugs in turn to alleviate the side effects – a fatal cycle – shock waves do penetrate the organism per se, but only for a short time and once: waves activate and regenerate cells and cell tissue in the microsecond range, but then dissipate and nothing remains. The organism is not burdened, the metabolism is not permanently infiltrated and contaminated by biochemical substances. So the advantages are obvious: this type of medicine is gentle, safe and highly effective. The medical maxim “Primo non nocere” – first of all do no harm – finds its equivalent in the field of shock wave therapies
Literature on shock wave research for the treatment of neurodegenerative diseases – see here:
https://www.alzheimer-germany.com/about-tps/tps-literature-and-studies
Literature on the mechanisms of action of shock waves in general:
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31 Grecco, M. V. et al.: One-year treatment follow-up of plantar fasciitis: radial shockwaves vs. conventional physiotherapy. Clinics, 68(8),1089 –1095, 2013.
32 Gleitz, M.: Die Bedeutung der Trigger-Stoßwellentherapie in der Behandlung pseudoradikularer Cervicobrachialgien. Abstracts 53. Jahrestagung der Vereinigung Süddeutscher Orthopäden e.V., 2005.
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