The Sensora: A Multi-Sensorial Therapeutic Device
(Part One)
by Anadi A. Martel, M.Sc., of Sensortech, Inc.
Abstract:
This article presents the “Sensora”, a new multi-sensorial device having therapeutic applications.
The Sensora is a whole environment integrating 3 sensorial sources: a colored light projection system, a spatialized sound system and a multi-transducer chair for kinesthetic stimulation. These 3 sources are driven by multi-media programs that allow the generation of a rich sensorial experience, with the potential of facilitating various processes such as relaxation and creativity enhancement, as well as more specialized therapeutic techniques. A description of the instruments comprising the system is given, followed by an explanation of the operating principles involved in the programs, and their applications.
1 Introduction
The Sensora is an electronic system belonging to a new class of devices that can be called, for want of a better name, “mind machines“. The purpose of these devices is to use technical means with the intention of having a beneficial influence on the mind, or more precisely on the body- mind, of users. Such beneficial influence can include relaxation, creativity enhancement, … as well as more specialized therapeutic processes.
The Sensora’s distinguishing characteristic is its integration of 3 different sensorial influences, hence it is being described as a “multi-sensorial” system. Many of the concepts involved in the Sensora are quite unique, and the technology it uses is amongst the most advanced in this relatively new field. In this article we will attempt to describe the operating principles of the system, so that a better understanding of what distinguishes it from other mind machines may be obtained.
2 Description of the System Components
Originating from early work on sound spatialization and EEG monitoring, the development of the Sensora has been ongoing for the past 15 years. Relying on experimentation with hundreds of individuals, we gradually evolved a method of combining sensorial stimuli into an integrated whole. Along the way we had to create and refine our own proprietary instruments, which now enable a multi-sensorial process involving light, sound and kinesthetic sources.
In this section we will briefly describe the different components that together make up the Sensora installation:
2.1 Light Projection
In the Sensora the user is exposed to light projections covering the whole field of vision.
This is achieved using three components:
Light Controller: A dedicated microcomputer, which we call the SD-1 Sensor Driver, generates the light patterns in real-time.
Light Projector:
The SD-1 digitally feeds a special light projector, which we call the LPA-1 Light Projection Array. This compact projector houses 15 discrete light sources with their associated digital power dimmers; the light sources are merged through fiber optic bundles into 5 groups of 3 primary colors, allowing the creation of any color through additive synthesis. The use of dichroic color filters ensure an excellent chromaticity, essential to the quality of the overall process.
Projection Screen:
The light patterns are projected on a large hemispherical screen, with a diameter of typically 3.5m for an individual installation. The screen has an inclination of about 45°, and the user reclines under it at a distance optimized to cover his/her field of vision. Its surface is coated with a special silvery compound to enhance the apparent depth of the light projections. When combined with the LPA-1 projector this results in an exceptional light quality, with an intensity and texture reminiscent of the vivid colors sometimes perceived in dreams.
The light patterns used in the Sensora are divided into 5 independent and overlapping zones, distributed horizontally along the width of the projection screen. The center of the screen is fitted with an extra independent point light source, which serves as a focal point around which the user can anchor his/her gaze.
2.2 Spatialized Sound
The Sensora soundtracks are re-mixed with our own Sound Spatialization Processors, which have already been used around the world for audio research and design. This enables the creation of a sound field surrounding the listener, where each sound can be positioned and delicately moved at will. The Sensora uses a 4-channel audio system to store and playback these spatialized soundtracks.
2.3 Transducer Chair
The kinesthetic stimulus of the Sensora is sound-based, generated using the following two components:
Transducer Controller:
A special microcomputer-driven audio processor, which we call the TD-1 Transdriver, extracts low-frequency information from a dedicated audio track. The TD-1 first stabilizes the audio signal through a sharp (48dB per octave) low-pass filter and a 2-stage AGC circuit; it then distributes it in programmable patterns across 8 discrete amplified channels.
Transducer Chair:
The 8 outputs of the TD-1 drive a special reclining chair, which we call the VIA Transducer Chair. The VIA chair contains an array of 8 audio transducers which can create a wave of vibration felt along the body as a kinesthetic sensation. The transducers are positioned in 2 rows of 4 across the chair surface, allowing transversal as well as longitudinal wave patterns.
Taken together, the TD-1 and the VIA chair can create a wide variety of vibration-wave patterns (e.g. up-down movements from head to feet, circles, crosses,… at varying speed and direction) which the user will perceive as having relaxing, stimulating or balancing effects.
2.4 Sensora Programs
All the instruments composing the Sensora system are digitally controllable and are designed to be driven by special multi-sensorial programs.
These programs contain the following elements:
– A digital track driving all the Sensora instruments
– 4 audio tracks containing the spatialized soundtrack
– A low-frequency audio track driving the Transducer Chair
This information is encoded using a proprietary technique and stored on special CDs. A Sensora session is played by simply accessing and starting the desired program. The process is then entirely automated, and does not require an operator.
We have already developed a library of Sensora programs that explores a good portion of the system’s vast possibilities, and new ones are being created as the research grows.
2.5 Room Environment
All the components of the Sensora system are installed in a dedicated room, typically with a 15m² area for an individual installation. The appearance of the room is carefully designed to contribute to the quality of the process.
The walls, floor and ceiling of the room are all black (either painted or carpeted). This has two functions:
– It enhances the optical quality of the light projections by minimizing reflections.
– On a subjective level, it contributes to the perception of the Sensora as a womb-like space with somewhat diffused, undefined boundaries which can also be felt as limitless; this helps to open the user’s mind to an “extra-ordinary”, deeper experience.
The large hemispherical screen obviously dominates the environment; with the black room surfaces and a subdued ambient lighting, it actually appears to be floating in a void.
Depending on the application, Sensora installations can be configured with one chair (for individual sessions), two chairs (allowing couples to share a Sensora session) or multiple chairs (such as for waiting rooms and other public installations).
Session Procedure:
The user sits on the Transducer Chair, under the screen. As the session starts, the chair reclines and the ambient lighting softly fades out. For the duration of the session the user simply rests, letting the light, sound and kinesthetic sources perform their function; he/she maintains an unfocused gaze towards the screen, letting the eyes occasionally close and open at will.
As the session ends, the room is left for a short while in quiet darkness, giving the user an opportunity to feel and savor the state in which the session has brought him/her. The ambient lighting then softly fades in, and the user brings the chair back to an upright position when he/she feels ready.
3 Operating Principles
In this section we examine the operating principles that have guided the design of the Sensora system. The intent behind the Sensora is ambitious: it is an attempt to blend art and science, using objective, scientific means to create a rich, aesthetic experience. The system’s development has drawn on many new fields of research, on the borderlines between technology, medicine, psychotherapy, psychology and art.
It must therefore be emphasized that while some of these operating principles are based on clearly established science data, a number of others are working hypotheses that have arisen out of both our own experimentation and of currently available worldwide research. These are presented here as pointers towards further research in this fascinating field.
3.1 Light Modulation:
“Light Modulation” is a unique process developed and patented by Sensortech, which is at the root of the effectiveness of the light projection patterns used in the Sensora. Essentially, Light Modulation applies to light the type of modulation processes that have long been applied to sound in audio synthesizers. This is achieved by using structures of Low Frequency Oscillators (LFOs) to control (i.e. to modulate) the intensity and color of light projections, in configurations of various complexities.
Programming Light Modulation patterns is somewhat similar to programming sound synthesizers, with a large number of parameters (up to 100 in the Sensora’s SD-1 Sensor Driver) defining the exact frequency, waveshape and phase of the many oscillators involved in the modulation structure.
The end result of this technique is the creation of shimmering, ever-changing light patterns that can have a remarkably organic quality of aliveness, or give a fleeting astral-like impression.
This imbues them with the ability to exert a visual fascination that is an essential factor in some of the operating principles described below. Also, the oscillatory nature of the modulation patterns naturally leads to the brainwave entrainment process described next.
When experimenting with such a powerful light-generating tool, it quickly becomes obvious that the frequencies used in cyclic light patterns can have a deep impact on the brain. A large portion of the expertise developed over the years of research into the Sensora is related to the selection and combination of sets of frequencies optimized for different types of sessions, whether for relaxation, stimulation or integration purposes.
In fact, organizing sequences of Light Modulation patterns to lead to pleasant and inspiring inner experiences has turned out to become a fascinating new art form in itself.
3.2 Brainwave Entrainment
The human brain generates weak electric signals called EEG (Electro-Encephalographic) waves, covering a frequency range of about 1 to 30 cycles per second (Hz). When the brain is exposed to pulsations of sound or light in the range of EEG wave frequencies, it tends to spontaneously harmonize with the pulsed frequencies. This phenomenon is known as photic driving (in the case of light) and has been widely studied. It has been found, for example, that stimulating the senses with pulsations in the Alpha range will help the brain to move toward the relaxed state normally associated with Alpha waves.
The Sensora is ideally suited to make use of this brainwave entrainment. A subset of the frequencies available in the Light Modulation process overlaps the frequency range of EEG waves, and the Sensora light projections can perform excellent photic driving. Sound entrainment can also easily be integrated in the Sensora soundtracks by embedding appropriate audio binaural beat frequencies.
While the research linking EEG waves and their associated mental states is complex and ongoing, their basic properties are by now well known and established. Their use in the programming of Sensora sessions is therefore one of its most systematic and objective operating principle.
EEG Phase Frequency Range Associated Properties
Beta 14 to 30Hz Brain waves in this range indicate the normal waking state. This is a state of mental activity and attention turned out towards the world. Most of us spend the majority of our waking hours in this state.
Alpha 8 to 13 Hz Alpha waves accompany relaxation. This state indicates attention turned inward, as in meditation and deep unwinding, let-go.
Theta 4 to 7 Hz The hypnagogic state just before falling asleep. This state plays an important role in visualization, creativity and learning.
Delta 1 to 4 Hz Delta waves appear during the deepest portions of sleep. They are also associated with states such as trance mediumship.
EEG Phases and their associated mental states
The complex nature of the Sensora light projections enable unique refinements in photic driving, not found in other simpler devices:
Modulation Depth Control:
Our experience has shown that some individuals find the use of raw light pulsations (such as in common brainwave entrainment light goggles) rather unpleasant or too intense; the Light Modulation parameters of the Sensora provide a fine proportional control over the modulation depth of light pulsations, allowing the generation of gentler pulsations which are more universally appreciated. This lower intensity does not detract from the overall experience, since brainwave entrainment is not the primary purpose of Sensora sessions but is only used as a support for the multi-sensorial process.
Enhanced Laterality Control:
It is well known that laterality is critical in brainwave activity, since each of the brain’s hemispheres is linked to different mental functions. In implementing effective brainwave entrainment, it is therefore important to be able to act on each hemisphere separately.
The optical nerve linking the retina of each eye to the brain is divided in two separate bundles channeling each eye’s left and right field of vision. The left and right bundles from each eye are then merged and crossed before reaching the brain’s visual centers. Therefore the combined left field of vision from both eyes reaches the right-brain hemisphere, while the combined right field of vision reaches the left-brain hemisphere.
Simple goggles with pulsing lights for each eye cannot completely resolve each brain hemisphere even when separately pulsing each eye, since each eye is partially linked to both hemispheres.
By contrast, the Sensora light projections are viewed on a large external screen and simultaneously reach both of the user’s eyes with the appropriate laterality: for example a pulsation projected on the left side of the screen will reach the same side of both eyes’ retina, and will be relayed through both left optical nerve bundles to the right-brain hemisphere only.
Peripheral Vision Temporal Sensitivity:
The retina’s central region (the fovea) has an enhanced spatial resolution, while the lateral regions have a higher temporal resolution: they can detect faster movements, but with less spatial details. A proposed explanation for this phenomenon is that it is an evolutionary adaptation to the need to react quickly to predator movements at the vision’s peripheral edge.
We have found that brainwave entrainment seems less obtrusive – while still remaining effective -when primarily performed on the peripheral lateral vision, and de-emphasized on the central vision. This makes sense since it optimally uses each vision’s specialization: the spatially sensitive fovea is less distracted by reduced central pulsations, while the peripheral vision is most tuned to the fast temporal variations of brainwave frequency pulsations.
As illustrated by the preceding three examples, the Sensora may be the only current instrument permitting such fine-tunings on brainwave entrainment light patterns.
(End of Part One)
Copyright: AVS Journal, Michael Landgraf, Publisher and Anadi Martel, Author. All rights reserved.