Related Application

[0001 ] This application claims priority from U.S. Provisional Application No. 61/813,331 , filed 18 April 2013, the subject matter of which is incorporated herein by reference in its entirety.

Technical Field

[0002] The invention is related to providing light therapy. The invention is related to measurement of heart rate variability related parameters from a patient, analyzing those and using the results of the analysis to control a light application device.

Background of the Invention

[0003] Light therapy can be given to patients or other users (hereafter referenced collectively as "patients"), for example, to treat seasonal affective disorder ("SAD"), anxiety, or any other desired condition. Devices such as the briteLITE 6 energy light, available from Philips International B.V. of the Netherlands, can be used to give light therapy to a patient.

[0004] Artificial optical radiation may be generated by bright light application devices in the form of the well-known bright light lamps. Recently a more elegant solution has been commercialized by Valkee Oy of Finland, in the form of the Valkee Brain Stimulation Headset described in WO 2008/029001 (the entire contents of which are incorporated herein by reference), wherein light emitting diode ("LED") light is provided to the brain via the auditory canal.

[0005] It can take few weeks before patients who are treated for SAD or other depressions respond to the therapy. This leads to problem of finding proper parameters for the light therapy treatment. Parameters that can typically be adjusted are needed therapy time (exposure of light), used power (brightness of the light) and used wavelengths (i.e. nm) of the light.

[0006] HRV refers to Heart Rate Variability. HRV is a noninvasive

electrocardiographic marker reflecting the activity of the sympathetic and vagal components of the autonomic nervous system ("ANS") on the sinus node of the heart. It expresses the total amount of variations of both instantaneous HR and RR intervals (intervals between QRS complexes of normal sinus depolarisations-see, e.g., http://www.cardionetics.com/ecg-durations [last accessed 14 April 2014]). Thus, HRV analyses the tonic baseline autonomic function. In a normal heart with an integer ANS, there will be continuous physiological variations of the sinus cycles reflecting a balanced sympthovagal state and normal HRV.

[0007] HRV can be measured with an ECG measurement device, which also can perform analysis to the measurement signal for ECG. The measured signal can be analysed in time domain and/or frequency domain.

[0008] The time domain analysis measures the changes in heart rate over time or the intervals between successive normal cardiac cycles. In a continuous ECG recording, each QRS complex is detected and the normal RR intervals (NN intervals), due to sinus depolarisations, or the instantaneous heart rate, are then determined. The calculated time domain variables may be simple, such as the mean RR interval, the mean heart rate, the difference between the longest and shortest RR interval, or the difference between night and day heart rate; and more complex based on statistical measurements. These statistical time domain indices are divided in two categories, including beat-to-beat intervals or variables derived directly from the intervals themselves or the instantaneous HR and intervals derived from the differences between adjacent NN intervals. Table 1 , below, summarizes the most frequently used parameters of the time domain. Parameters of the first category are SDNN, SDANN and SD and those of the second category are RMSSD and pNN50.

[0009] SDNN is a global index of HRV and reflects all long-term components and circadian rhythms responsible for variability in the recording period. SDANN is an index of the variability of the average of 5-minute. Thus, it provides long-term information. It is a sensitive index of low frequencies like physical activity, changes in position, circadian rhythm. SD is generally considered to reflect the day/night changes of HRV. RMSSD and pNN50 are the most common parameters based on interval differences. These measurements correspond to short-term HRV changes and are not dependent on day/night variations. They reflect alterations in autonomic tone that are predominantly vagally mediated. Compared to pNN50, RMSSD seems to be more stable and should be preferred for clinical use.

Table 1 : Frequently used parameters of the time domain

[0010] The measured heart rate signal (with ECG) can be also analysed in frequency domain. In practice FFT analysis is often used.

[001 1 ] When using the FFT, the individual RR intervals stored in the computer are transformed into bands with different spectral frequencies. This process is similar to decomposing the sound of a symphony orchestra into the underlying notes. The results obtained can be transformed in Hertz (Hz) by dividing by the mean RR interval length.

[0012] The power spectrum consists of frequency bands ranging from 0 to 0.5 Hz and can be classified into four bands, summarized in Table 2, below: the ultra low frequency band ("ULF"), the very low frequency band ("VLF"), the low frequency band ("LF") and the high frequency band ("HF"). Table 2: Frequency bands

ra o ra o o ow- g requency power

[0013] Short-term spectral recordings (5 to 10 minutes) are characterized by the VLF, HF and LF components, while long-term recordings include a ULF component in addition to the three others. The total power of RR interval variability is the total variance and corresponds to the sum of the four spectral bands, LF, HF, ULF and VLF.

Summary

[0014] In an embodiment, a light therapy apparatus for affecting baroreflex of a patient is described. A light application device is provided for directing optical radiation energy from an optical radiation source non-invasively to intracranial nerve tissue of a patient via direct provision of the optical radiation energy to an external auditory canal of the patient. An ear adapter is provided for maintaining the light application device in a predetermined position with respect to an auricle of the subject for administration of light via the external auditory canal. A controller unit is provided for receiving heart rate data for the patient and responsively adjusting at least one of application time, application location, applied wavelength(s), applied intensity levels of each wavelength, and applied total intensity level(s) of optical radiation energy provided to the external auditory canal by the light application device to affect baroreflex of the patient.

[0015] In an embodiment, a method of affecting baroreflex of a patient is described. Optical radiation energy is directed from an optical radiation source non- invasively to intracranial nerve tissue of a patient via direct provision of the optical radiation energy to an external auditory canal of the patient. Heart rate data for the patient is received. At least one of application time, application location, applied wavelength(s), applied intensity levels of each wavelength, and applied total intensity level(s) of optical radiation energy provided to the external auditory canal by the light application device is adjusted responsive to the received heart rate data to affect baroreflex of the patient.

Brief Description of the Drawings

[0016] For a better understanding of the invention, reference may be made to the accompanying drawings, in which:

[0017] Fig. 1 is a front view of a light therapy apparatus which can be used with one embodiment;

[0018] Fig. 2 is a schematic view of a component of the embodiment of Fig. 1 ;

[0019] Fig. 3 shows various spectral compositions of LED's of certain types;

[0020] Fig. 4 is a schematic view of a patient with a system including the light therapy apparatus of the embodiment of Fig. 1 ;

[0021 ] Fig. 5 is a schematic view of the system of Fig. 4;

[0022] Fig. 6 is a schematic view of a computer system that can be employed to implement systems and methods described herein, such as based on computer executable instructions running on the computer system;

[0023] Figs. 7-8 are charts showing some experimental results achieved using the embodiment of Fig. 1 .

Description of Embodiments

Devices and apparatuses:

[0024] In accordance with the present invention, Fig. 1 depicts a patient light device 2 such as, but not limited to, the Valkee Brain Stimulation Headset available from Valkee OY of Oulu, Finland (www.valkee.com) for providing light therapy. The patient light device 2 of Fig. 1 may include integrated functionality to receive a signal from any suitable portable or nonportable electrocardiography machine and/or other suitable type of commercial or consumer heart rate monitoring system (such as, but not limited to, one or more of the heart rate monitor products available from Polar Electro Inc. of Lake Success, New York) and/or to receive any signal indicative of heart rate. The received signal-whether it is a direct heart rate signal or another data input which is indirectly indicative of heart rate-may be processed to monitor the effects of the light therapy treatment on the patient, with the light output parameters changed responsive to the received heart rate signal. It is also contemplated that light therapy could be used to impact HRV of the patient in a desired manner.

[0025] The present invention is at least partially based upon the observation that certain HRV related parameters change relatively fast (within minutes) if the light therapy via ear canals is done with a predetermined light spectrum for the patient. This observation can be used in a device to modify and/or ensure validity of the light therapy treatment parameters for that patient, including, but not limited to, wavelengths, energy, intensity per wavelength area, relative intensities per wave length areas, treatment times, total output power, or any other parameters).

[0026] The patient light device, a portion of which is shown generally as element 2 in Fig. 1 , has a control unit 3 with an on/off button. Optionally, other user interface ("III") functions are also provided to the patient light device 2 (e.g., on the control unit 3 or any other portion of the device) to allow a user or patient to view and/or affect settings, results, and other parameters related to therapy provided by the patient light device 2. There are two wires 4 coming out of the patient light device 2. At the end of each of the wires 4 there is an ear plug 6 (the patient light device 2 has one for each ear) that emits light to the ear with specified wavelength for specific duration. The patient light device 2 has connector 8 in the bottom of the device. The connector 8 can be used to charge the patient light device 2 as well as provide communication with the between at least a portion of the patient light device 2 and any other outside element using wired connection (such as USB). The patient light device 2 could also or instead include wireless connection means, such as, but not limited to, Bluetooth.

[0027] Fig. 3 shows a detailed view of an example ear plug 6 which can be used with an embodiment of the present invention. The ear plug 6 may serve as part of a light application device 100 for directing optical radiation energy 102 from an optical radiation source 104 non-invasively to intracranial nerve tissue of a patient via direct provision of the optical radiation energy to an external auditory canal of the patient.

[0028] The ear plug 6 may comprise an optically permeable part 106, which allows optical radiation energy 102 to pass therethrough and forms a structure protecting the optical radiation source 104. The optically permeable part 106 may be a structure (e.g., a transparent and/or translucent structure) and may also or instead comprise an opening or aperture in a housing of the ear plug 6.

[0029] The optical radiation source 104 is an electro-optical component which converts electric power into optical radiation energy 102. The optical radiation source 104 may be, for example, a bulb, light diode, or diode laser. Electric power may be transferred into the optical radiation source 104 along a wire 4 from the control unit 3. The optical radiation source 104 may comprise one or more optical radiation sub- sources (e.g., individual LEDs), each of which may have an optical radiation sub- source-specific spectral and/or spatial distribution of optical radiation.

[0030] In an embodiment, the spectral distribution of the optical radiation source 104 may be controlled. In an embodiment, the optical radiation source 104 comprises RGB (red-green-blue) LEDs, which may together produce a spectrum of optical radiation at a visible wavelength. The spectral distribution of optical radiation may be weighted by controlling or driving each LED separately using a different amount of current. A corresponding LED arrangement may be implemented by infrared LEDs, for instance. Further light intensity output of each LED can be controlled, for example, by pulse width modulation (PWM) also or instead of controlling the currents via each LED. The LEDs may be connected in series or in parallel. The connection in series provides the advantage that the same current passes through several LEDs, which may provide savings in the total consumption of power as compared to the connection in parallel.

[0031 ] In an embodiment, the optical radiation source 104 may be selected or configured so that the wavelength of the optical radiation energy 102 is at least partially in the area of blue color.

[0032] In an embodiment, the optical radiation source 104 may be selected or configured so that the wavelength of the optical radiation energy 102 is at least partially in the area of red color. In that case, the absorption of optical radiation energy 102 is slight and the amount of optical radiation directed at the intracranial nerve tissue is larger compared to a case where absorption is stronger.

[0033] In an embodiment, the optical radiation source 104 may be selected or configured so that the wavelength of the optical radiation energy 102 is at least partially in the infrared area, in which case the effect of the optical radiation energy 108 is directed at target tissues sensitive to thermal radiation, such as the vestibular organ. In this case, the radiation source is an infrared diode, for instance.

Alternatively or additionally, a heat element, such as a resistor, can be used as a thermal radiation source.

[0034] Fig. 3 shows examples of measurements of the spectral power (Watts per nanometer) of five type "B" LED's which may be used to treat patients. Type B spectra have been found in a number of conducted experiments to be helpful in curing SAD-related symptoms, for example. From Fig. 3, it can be seen that the blue peak wavelength is at approx. 448 nm with a half peak width of about 30 nm. The peak starts from about 418 nm and reaches to about 480nm. There is some "red" light with the peak at 562nm. Additionally, for example, it has been found that Type B spectra have been efficient on curing urinary incontinence. For some patient type B spectra have been found to help on, e.g. reduce symptoms of, anxiety and migraine. The spectral output from 380 nm to 480 nm (blue peak) is between 6.1 -7.8 mW for the five spectra. The spectral output from 481 to 780 nm (red peak) is between 8.5 and 10.9 mW for the five spectra. The total power is thus between 14.6 and 18.8 mW. The ratio between the blue and red light of the five type B LEDs may be between 0.65 and 0.75, such as between 0.65 and 0.70, such as between 0.70 and 0.75, and such as between 0.678 and 0.719.

[0035] Turning back to Fig. 2, an ear adapter 108 may be provided for maintaining the ear plug 6, or any other portion of the light application device 100 (e.g., the optical radiation source 104) in a predetermined position with respect to an auricle of the subject for administration of light via the external auditory canal. For example, Fig. 2 includes an ear adapter 108 for the placing the optical radiation source 104 at the mouth of the external auditory canal and/or on an auricle (external ear structure) of the patient. The ear adapter 108 may be, for example, a plug-like structure which is made of plastic, rubber, or any other desired material, which may be generic/stock or custom-fit for a particular patient, and which may at least partly penetrate into the patient's external auditory canal.

[0036] In an embodiment, the optical radiation source 104 may include one or more sound channels 1 10, which form an air-filled channel between the auricle and the external auditory canal, for instance. The sound channel(s) 1 10 may be helpful in transmitting air pressure differences caused by external sounds to the patient's eardrum. This allows the patient to hear outside/ambient noise during use of the light application device 100.

[0037] In an embodiment, the optical radiation source 104 may be integrated into and/or used as a hearing aid, in which case the light application device 100 and/or another portion of the patient light device 2 may include a sound source connected to a microphone unit, and/or other hearing aid components, integrated into the light application device 100 or provided separately therefrom.

[0038] As shown in Fig. 2, the optical radiation source 104 and the ear adapter 108 form an integrated structure. In this Figure, the optical radiation source 104 is substantially inside the ear adapter 108. However, it is contemplated that other arrangements (e.g., using an optical fibre or other light guide, not shown) could be used with the patient light device 2.

[0039] While the light application device 100 shown in Fig. 2 is provided as an example, the description herein is agnostic as to the medical device used and does not presume the use of any particular device, whether or not described herein.

[0040] As shown schematically in Fig. 4, a patient 1 can use a light therapy apparatus 150. The patient light device 2 has wires 4 providing electricity to ear plugs 6. The ear plugs 6 may provide light into the ear (more specifically, into the external auditory canal), as discussed above.

[0041 ] A controller unit 152 may receive heart rate data for the patient and responsively adjusting at least one of application time, application location, applied wavelength(s), and applied intensity level(s) of optical radiation energy 108 provided to the external auditory canal by the light application device 100 to affect baroreflex of the patient, as will be discussed below. The controller unit 152 and patient light device 100 are each parts of the light therapy apparatus 150. [0042] For example, the controller unit 152 (shown in Fig. 4 as being integrated into the patient light device 2) may receive input from a heart rate (ECG)

measurement device 154 in any desired manner/format, such as via a wireless connection 156, though a wired connection could also or instead be provided. The controller unit 152, or any other desired portion of the light therapy apparatus 150 may calculate time domain (SDNN, SDANN, SD, etc.) and/or frequency domain components (VLF, LF, etc.) of the measured signal.

[0043] Optionally, and as shown in Fig. 4, a communication adapter 158 can operatively connect the light application device 100 to an external control device 160 (such as through the depicted wireless communications), and the controller unit 152 can adjust the optical radiation energy 108 responsive to instructions received from the external control device 160.

[0044] Fig. 5 shows a schematic view of an example light therapy apparatus 150 of the present invention. The patient 1 is measured/observed with a heart rate measurement device 154 and/or a blood pressure measurement device (not shown separately, but which could be integrated into the heart rate measurement device 154). The heart rate measurement device 154 sends to controller unit 152 a signal, e.g., from a heart rate measurement sensor and/or a blood pressure sensor. The signal can be raw data or it can be processed data, as desired for a particular use environment.

[0045] The controller unit 152 uses input to send commands to the patient light device 2 which provides light to the subject (via ear, such as by use of a light application device 100). Commands can include on/off, intensity, wavelengths, spatial distribution, spectral distribution, temporal distribution, and/or any other desired commands. In other words, the controller unit 152, an external control device 160, and/or any other portion of the light therapy apparatus 150 can receive heart rate and/or blood pressure data for the patient and responsively adjust (e.g., by providing instructions to the controller unit 152) at least one of application time, application location, applied wavelength(s), and applied intensity level(s) of optical radiation energy provided to the external auditory canal by the light application device 100 to affect baroreflex of the patient 1 , as described herein. [0046] Depending on the implementation of the system, for example, the patient light device 2 and controller unit 152 could be integrated into a single device, all components of the system of the Figures could be integrated into a single device, or some or all of the components shown and described herein could be separately provided. In some embodiments, the instructions can come from a server system acting as a remotely located controller unit 152. That is, the modules and

components of the system do not have all to be in the same physical place.

[0047] Regarding the controller unit 152, processing of the signals from the heart rate measurement device 152 in order to derive commands can be done, for example, using "standard" feedback control algorithms known from process control theory. One example of such is a proportional integral derivative ("PID") controller. Processing of sensor signal can be also done as model predictive control ("MPC") where physiological modelling of the patient may be taken in account. Modelling parameters can include medication used, age, weight, diagnoses, and/or any other desired parameters.

[0048] Additionally or alternatively, the light therapy apparatus 150 can have preprogrammed spectral characteristics (intensities, relative peak intensities, spectral and/or spatial distribution, time of treatment, used wavelengths, or the like) of optical radiation without an included feedback loop from the heart rate monitoring system. Such settings can be preprogrammed per patient type (gender, age, symptoms, genetics, or the like), per device model, according to diagnosis, and/or based on a desired effect, such as affecting baroreflex. for example. Additionally the settings can also or instead be made at initialization phase (for example, by medical personnel or by a manufacturer/merchant) for each user, and then used without further monitoring of the patient's heart rate and/or blood pressure signal during use.

[0049] Fig. 6 illustrates a computer system 382 that can be employed to implement systems and methods described herein, such as based on computer executable instructions running on the computer system. The user may be permitted to preoperatively simulate the planned surgical procedure using the computer system 382 as desired. The computer system 382 can be implemented on one or more general purpose networked computer systems, embedded computer systems, routers, switches, server devices, client devices, various intermediate devices/nodes and/or stand alone computer systems. Additionally, the computer system 382 can be implemented as part of the computer-aided engineering (CAE) tool running computer executable instructions to perform a method as described herein.

[0050] The computer system 382 includes a processor 384 and a system memory 386. Dual microprocessors and other multi-processor architectures can also be utilized as the processor 384. The processor 384 and system memory 386 can be coupled by any of several types of bus structures, including a memory bus or memory controller, a peripheral bus, and a local bus using any of a variety of bus

architectures. The system memory 386 includes read only memory (ROM) 388 and random access memory (RAM) 390, which can both be considered computer- readable storage media. A basic input/output system (BIOS) can reside in the ROM 388, generally containing the basic routines that help to transfer information between elements within the computer system 382, such as a reset or power-up.

[0051 ] The computer system 382 can include one or more types of long-term data storage 392 or other computer-readable storage media, including a hard disk drive, a magnetic disk drive, (e.g., to read from or write to a removable disk), and an optical disk drive, (e.g., for reading a CD-ROM or DVD disk or to read from or write to other optical media). The long-term data storage 392 can be connected to the processor 384 by a drive interface 394. The long-term data storage 392 components provide nonvolatile storage of data, data structures, and computer-executable instructions for the computer system 382. A number of program modules may also be stored in one or more of the drives as well as in the RAM 390, including an operating system, one or more application programs, other program modules, and program data.

[0052] A user may enter commands and information into the computer system 382 through one or more input devices 396, such as a keyboard or a pointing device (e.g., a mouse). These and other input devices are often connected to the processor 384 through a device interface 398. For example, the input devices can be connected to the system bus by one or more a parallel port, a serial port or a universal serial bus (USB). One or more output device(s) 400, such as a visual display device or printer, can also be connected to the processor 384 via the device interface 398. [0053] The computer system 382 may operate in a networked environment using logical connections (e.g., a local area network (LAN) or wide area network (WAN) to one or more remote computers 402. A given remote computer 402 may be a workstation, a computer system, a router, a peer device or other common network node, and typically includes many or all of the elements described relative to the computer system 382. The computer system 382 can communicate with the remote computers 402 via a network interface 404, such as a wired or wireless network interface card or modem. In a networked environment, application programs and program data depicted relative to the computer system 382, or portions thereof, may be stored in memory associated with the remote computers 402, which can also be considered a computer-readable storage medium.

Baroreflex:

[0054] Baroreflex is a very powerful short-term mechanism that regulates arterial pressure. It is a negative feedback loop that prevents inappropriate decreases and increases in arterial pressure by adjusting autonomic input to the heart and blood vessels based on afferent input originating from baroreceptors in the aortic arc and carotid sinuses. Impaired baroreflex function, indicated by decreased baroreflex sensitivity (BRS) or gain, has a notable effect in several cardiovascular (CV) and metabolic disease conditions. Impaired BRS is associated with abnormal autonomic function that normally manifests as decreased vagal and increased sympathetic activity. Reduced BRS is an existing feature of the most common CV and metabolic diseases, including metabolic syndrome, hypertension, type 2 diabetes, and coronary artery disease, and is a powerful predictor of future CV complications in patients with a known cardiac disease. Although the prognostic significance of impaired BRS has been proven in observational studies of patients with cardiac disease, BRS as a predictor of clinical outcomes in the general population is not known. Secondly, the considerable inter-individual variance in BRS is poorly understood, which limits implementation of BRS measures in clinical practice and early prevention. This variance is only partly explained by demographic, metabolic, and environmental factors, suggesting a large genetic component.

Interestingly, there is increasing evidence of the impact of early life developmental patterns on the development and maintenance of metabolic homeostasis and CV health in adulthood, which may also explain the variance in CV risk markers such as BRS. However, the contribution of fetal and life-course development to BRS is an area of research which bears further exploration.

[0055] The sensitivity of baroreflex is composed of three main components. First, BRS is dependent on sensation of arterial transmural pressure changes by baroreceptors, which is limited by compliance (stiffness) of the aortic arc and carotid sinus observed with development of atherosclerosis and sympathetic overactivity. Secondly, autonomic activity of the heart and blood vessels is largely determined by the central nervous system, which resets the baroreflex to maintain the desired arterial pressure and homeostasis. The final autonomic responses of the heart and blood vessels are affected by the density and sensitivity of adrenergic and cholinergic receptors as well as the functional properties of the end-organs.

[0056] Baroreflex sensitivity, more specifically cardiovagal BRS, is an important variable being studied in relation to the present invention. BRS will be measured using state-of-the-art techniques that quantify BRS noninvasively from spontaneous fluctuations in arterial pressure and R-R interval (e.g., sitting and standing, both 3 min) and during the Valsalva maneuver (e.g., exhalation against 40 mmHg for 15 s). Electrocardiogram (lead II, such as available from Cardiolife, Nihon Kohden, Japan), finger blood pressure (Nexfin, such as available from BMEYE, The Netherlands), breathing frequency (Nasal Temperature Probe, such as available from ADInstruments, Australia), and/or any other desired traits of the patient will be recorded as desired, e.g., with a Powerlab data acquisition system (available from ADInstruments, Australia) with a sampling frequency of, for example, 1000 Hz. R-R intervals and corresponding values of systolic blood pressure may be extracted from the data for subsequent analysis of baroreflex sensitivity by a cross-spectral method and by the slope between systolic blood pressure and R-R interval during the arterial pressure overshoot phase in three Valsalva maneuvers. A transfer function (cross- spectral analysis) and regression (Valsalva) may be employed to verify that the relationship between changes in arterial pressure and subsequent changes in R-R interval reflect baroreflex physiology. Methods:

[0057] Application of light to a patient's intracranial nerve tissue, such as via the light therapy apparatus 150 described and shown herein, may be helpful in positively affecting baroreflex of a patient. For example, optical radiation energy from an optical radiation source can be directed non-invasively to intracranial nerve tissue of a user via direct provision of the optical radiation energy to an external auditory canal of the patient (such as via the light therapy apparatus 150). Before, during, and/or after the direction of lights, heart rate and/or blood pressure data for the patient can be received. For example, data regarding heart rate and/or blood pressure can be obtained using a heart rate (and/or blood pressure) measurement device 154 and provided, in any suitable manner, to an external control device 160, a controller unit 152, and/or a light application device 100.

[0058] At least one of application time, application location, applied

wavelength(s), applied intensity levels of each wavelength, and applied total intensity level(s) of optical radiation energy provided to the external auditory canal by the light application device can then be adjusted responsive to the received heart rate and/or blood pressure data to affect baroreflex of the patient. The adjusted factor(s) may be adjusted by provision of appropriate instructions, for example, to the light application device 100, such as via the patient light device 2 and/or the external control device 160. In the latter example, an external control device 160 can be operatively connected to the light application device 100 via a communication adapter 158. The optical radiation energy 108 can then be adjusted, with the controller unit 152, responsive to instructions received from the external control device 160.

[0059] The below steps (1 )-(6) describe an example method of use of the present invention:

1 ) Measuring time domain and frequency components of ECG before the light (e.g., light from a light application device 100) is turned on, and/or performing the same measurements during use of the light when the method is an ongoing loop-type control.

2) Turning light on with initial settings (or modified as per step 4 in a loop-type control method according to this description).

3) Measuring change in time domain and frequency domain components. 4) If a desired baroreflex change is not observed after a set time limit, aborting the treatment and/or changing parameters of the treatment (such as intensity and/or wavelength (colour) of the light). Control of this method then returns to step 1 .

Change of settings may be basically an iterative process. The algorithm can be based on one or more of the below inputs (a)-(g) or on any other desired inputs: a) Systematically testing parameters

b) Selecting from set of pre-programmed settings (of time + wavelengths +

intensities)

c) Using iterative optimization algorithms to find parameters.

d) Using neural network type algorithms

e) Connecting to server (e.g., a server of a light application device manufacturer, a medical provider, or any other source) to download new parameters based on the patient's profile and measurement results

f) Randomly

g) PID controller (proportional integral derivative)

[0060] If a desired baroreflex change (for example, an increase of SDNN) is observed, continue the treatment as long as the desired baroreflex change continues (e.g., the SDNN value increases or is maintained at a desired value).

[0061 ] When the baroreflex change (e.g., increasing SDNN value) has stopped, stop the treatment and record/store time of the treatment as well as other parameters of the treatment, for future reference and, optionally, for helping control future sessions of the same patient with the light therapy apparatus 150.

[0062] An experimental study was conducted to test whether light therapy applied via ear-canal has an impact on heart rate variability. Previous studies conducted by the assignee of this patent application suggests that intracranial tissue- targeted light treatment via external auditory canals may have physiological effects on brain function studied by functional magnetic resonance imaging techniques in humans. The inventors of the present invention tested the hypothesis that acute intracranial tissue-targeted light treatment via external auditory canals may have effects also on autonomic regulation in mild hypertensive subjects. [0063] Hypertensive men without any medication participated in the study (n=19, age 61 ±3 years, systolic blood pressure 140-160 and/or diastolic blood pressure 90-100 mmHg during one week follow up at home).

[0064] In a blinded study design, a twelve minute dose of bright light treatment or placebo treatment were administered in a random order on separate days by a transcranial bright light device via the ear canals (blue based LEDs).

[0065] Blood pressure and ECG were measured during the treatments. Heart rate variability was analyzed in 5 minute periods at baseline, at the end of treatment, immediately following treatment, and from 7 to 12 minutes after treatment. Standard deviation of RR intervals (SDNN) and high (HF), low (LF), and very low (VLF) frequency powers of RR intervals were calculated by standard spectral techniques. Analysis of variance for repeated measures with time x group interaction was performed for the measured variables.

[0066] There was no time x group interaction in heart rate or blood pressure. SDNN and VLF power increased during the bright light treatment but not during the placebo treatment (time x group interaction p=0.019 and p=0.040 for SDNN and VLF, respectively). VLF power was 6.7±0.7 vs. 6.6±0.6 In ms ² (p=ns) at baseline for bright light treatment and placebo, respectively. The corresponding VLF values for bright light and placebo were 7.0±0.7 vs. 6.6±0.7 (p=0.034) at the end of treatment, 7.3±0.7 vs. 6.8±0.7 (p=0.013) immediately after treatment and 6.9±0.5 vs. 6.9±0.6 In ms ² (p=ns) at the end of the recordings. LF or HF power did not differ between treatments (interaction p=0.33 for both).

[0067] The results of this blinded and placebo controlled trial provide evidence that acute intracranial tissue-targeted light treatment via external auditory canals has effects on cardiovascular autonomic regulation in hypertensive males documented by increasing long-term heart rate variability indices.

[0068] In addition, it was shown that an acute bright light treatment has no harmful effects on heart rate or blood pressure in hypertensive males. An acute bright light treatment increases global heart rate variability in hypertensive males. This may be a positive health effect since reduced heart rate variability is an independent risk marker for cardiovascular events [0069] Fig. 7 shows significant acute change in hormonal and neural blood pressure control variables HLV and VF, and global HRV, all positively affected.

Blinded, placebo-controlled setting was used as described earlier. Fig. 7 shows SDNN before treatment (baseline), during the treatment (light), and at two points after the treatment.

[0070] Effects of light on BRS in low frequency band are shown in Fig. 8.

[0071 ] Fig. 9 demonstrates significant acute change in baroreflex, a well- established arterial pressure control variable.

[0072] Currently, the inventors are aware of no medical methods for adjusting / changing HRV of a patient. According to embodiments of the present invention, and as supported by the experiment described above, a light therapy apparatus 150 can be used to control a patient's heart rate variability. It is evident from the experiment that positive changes (i.e. increases) of SDNN was observed during the light therapy via ear.

[0073] According to embodiments of the present invention, periodic treatment with light therapy during long periods (such as weeks or months) can lead to permanent improvement on HRV.

[0074] While aspects of this disclosure have been particularly shown and described with reference to the example embodiments above, it will be understood by those of ordinary skill in the art that various additional embodiments may be contemplated. For example, the specific methods described above for using the apparatus are merely illustrative; one of ordinary skill in the art could readily determine any number of tools, sequences of steps, or other means/options for placing the above-described apparatus, or components thereof, into positions substantively similar to those shown and described herein. Any of the described structures and components could be integrally formed as a single unitary or monolithic piece or made up of separate sub-components, with either of these formations involving any suitable stock or bespoke components and/or any suitable material or combinations of materials; however, the chosen material(s) should be biocompatible for many applications. Any of the described structures and

components could be disposable or reusable as desired for a particular use environment. Any component of the invention could be provided with a user- perceptible marking to indicate a material, configuration, at least one dimension, or the like pertaining to that component, the user-perceptible marking aiding a user in selecting one component from an array of similar components for a particular use environment. A "predetermined" status may be determined at any time before the structures being manipulated actually reach that status, the "predetermination" being made as late as immediately before the structure achieves the predetermined status. Though certain components described herein are shown as having specific geometric shapes, all structures of this disclosure may have any suitable shapes, sizes, configurations, relative relationships, cross-sectional areas, or any other physical characteristics as desirable for a particular application. Any structures or features described with reference to one embodiment or configuration of the invention could be provided, singly or in combination with other structures or features, to any other embodiment or configuration, as it would be impractical to describe each of the embodiments and configurations discussed herein as having all of the options discussed with respect to all of the other embodiments and configurations. A device or method incorporating any of these features should be understood to fall under the scope of this disclosure as determined based upon the claims below and any equivalents thereof.

[0075] Other aspects, objects, and advantages of the invention can be obtained from a study of the drawings, the disclosure, and the appended claims.