DETERMINING PHYSIOLOGICAL STATE(S) OF AN ORGANISM BASED ON DATA SENSED WITH SENSORS IN MOTION
Embodiments of the invention relate generally to electrical and electronic hardware, computer software, wired and wireless network communications, and wearable computing devices for facilitating health and wellness-related information. More specifically, disclosed are electrodes and methods to determine physiological states using a wearable device (or carried device) and one or more sensors that can be subject to motion. In one embodiment, a method includes receiving a sensor signal including data representing physiological characteristics in a wearable device from a distal end of a limb and a motion sensor signal. The method includes decomposing at a processor the sensor signal to determine physiological signal components. A physiological characteristic signal is generated that includes data representing a physiological characteristic, which can form a basis to determine a physiological state based on, for example, bioimpedance signals originating from the distal end of the limb.
1 . A method comprising:
receiving a sensor signal including data representing physiological characteristics in a wearable device, the wearable device being configured to receive the sensor signal from a distal end of a limb at which the wearable device is disposed;
receiving a motion sensor signal;
decomposing at a processor the sensor signal to determine physiological signal components and motion signal components based on the sensor signal and the motion sensor signal;
generating a physiological characteristic signal that includes data representing a physiological characteristic; and
determining a physiological state based on at least the physiological characteristic derived from the sensor signal originating at the distal end.
2 . The method of claim 1 , wherein receiving the sensor signal comprises:
receiving the sensor signal during one or more portions of the time interval during which the wearable device is in motion.
3 . The method of claim 1 , wherein receiving the sensor signal comprises:
receiving a bio-impedance signal from the distal end of the limb at which the wearable device is disposed.
4 . The method of claim 1 , wherein generating the physiological characteristic signal that includes the data representing the physiological characteristic comprises:
generating the physiological characteristic signal that includes the data representing one or more of a heart rate, a respiration rate, and a Mayer wave rate.
5 . The method of claim 4 , wherein determining the physiological state further comprises:
determining a stage of sleep based on at least the heart rate and the respiration rate.
6 . The method of claim 5 , further comprising:
determining regularity of the heart rate and the respiration rate; and
generating a signal indicating the stage of sleep is associated with a non-REM sleep state.
7 . The method of claim 6 , further comprising:
determining the motion sensor signal includes at least a portion of motion indicative of involuntary muscle twitching.
8 . The method of claim 6 , further comprising:
generating a wake enable signal to enable the wearable device to generate an alarm signal to wake a user during the non-REM sleep state.
9 . The method of claim 5 , further comprising:
determining variability of the heart rate and the respiration rate; and
generating a signal indicating the stage of sleep is associated with a REM sleep state.
10 . The method of claim 9 , further comprising:
determining the motion sensor signal includes a negligible amount of motion associated with the REM sleep state.
11 . The method of claim 9 , further comprising:
generating a wake disable signal to disable the wearable device to prevent generation of an alarm signal to wake a user during the REM sleep state.
12 . The method of claim 1 , further comprising:
determining the motion sensor signal includes a portion of motion associated with a tremor; and
characterizing the tremor as a malady based on at least data representing user characteristics.
13 . The method of claim 12 , further comprising:
transmitting data representing an indication of the presence of the malady via a wireless communication link.
14 . The method of claim 12 , wherein characterizing the tremor as the malady comprises:
determining the malady is associated with data indicative of one of epilepsy, Parkinson's disease, and diabetes of which the tremor is a diabetic tremor.
15 . The method of claim 1 , wherein generating the physiological characteristic signal comprises:
generating the physiological characteristic signal that includes the data representing one or more of a heart rate, a respiration rate, and a skin conductance signal; and
determining the physiological state as a pain state based on at least the skin conductance signal.
16 . The method of claim 1 , wherein generating the physiological characteristic signal that includes the data representing the physiological characteristic comprises:
generating the physiological characteristic signal that includes the data representing a Mayer wave rate;
determining heart rate variability (“HRV”) based on the Mayer wave rate; and
determining the malady based on the HRV.
17 . The method of claim 1 , wherein determining a physiological state comprises:
determining an affective state of a user wearing the wearable device.
18 . The method of claim 1 , wherein decomposing the sensor signal comprises:
performing independent component analysis (“ICA”) to separate physiological signal components and motion signal components; and
using the physiological signal components to determine the physiological state.
19 . An apparatus comprising:
a wearable housing configured to couple to a portion of a limb at its distal end;
a motion sensor configured to sense motion associated with the wearable housing and to generate a motion sensor signal;
one or more electrodes disposed in the wearable housing configured to receive a sensor signal including data representing one or more physiological characteristics during one or more portions of a time interval in which the wearable device is in motion; and
a processor configured to execute instructions to implement a motion artifact reduction unit that is configured to:
extract from the sensor signal, which includes a signal component associated with motion artifacts, to determine a physiological signal based on the sensor signal and the motion sensor signal;
generate a physiological characteristic signal that includes data representing the physiological characteristic during at least one of the one or more portions of the time interval, the physiological characteristic including data representing one or more of a heart rate and a respiration rate; and
determine a physiological state based on the one or more of the heart rate and the respiration rate derived from the sensor signal originating at the distal end.
20 . The apparatus of claim 19 , wherein the processor further configured to execute instructions to implement a sleep manager that is configured to:
determine a stage of sleep; and
enabling or disabling an alarm based on the stage of sleep.