Discriminating between an awake phase and a sleep phase of a patient in an active implantable medical device
First Claim
1. An active medical, device, comprising:
- (a) means for measuring a physiological parameter of a patient and delivering a physiological signal;
(b) means for detecting an awakening phase and a sleep phase of the patient, including;
a first comparator means for computing an average value of the measured physiological signal over a first period, and comparing said average with a predetermined physiological threshold; and
(c) means for indicating a first state of the patient as an awakening state in response to the average being greater than said physiological threshold, and as a sleep state otherwise;
(d) means for measuring an activity parameter of the patient and producing a physical signal corresponding to said activity parameter;
(e) second comparator means for comparing the measured physical signal with a predetermined activity threshold; and
(f) means for indicating a second state of the patient as an awakening state in response to said activity signal being greater than said activity threshold, and as a sleep state otherwise;
(g) means for comparing the first state of the patient with the second state of the patient; and
(h) anticipating means for selectively modifying the period of said first comparator means in response to a discordance between the aforementioned first and second states of awakening or sleep.
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Abstract
An active medical device having an improved discrimination between an awake phase of a patient and a sleep phase of a patient. This device measures a physiological parameter of a patient, delivers a physiological signal with a slow time response variation, in particular a signal of minute-ventilation (signal MV), and detects whether the patient is in a phase of awakening or sleep. An average (VE) of the signal MV is calculated over a given number of respiratory cycle and compared with a predetermined threshold (Threshold MV), such that a first state of awakening is determined when the average is higher than the threshold, and a first state of sleep is determined in the contrary case. The device also measures patient activity (signal G), using a signal having a short response time. The activity signal is compared with a predetermined threshold (Threshold G), and a second state of the patient is determined to be an awakening phase when the activity signal is higher than the threshold, and a sleep state in the contrary case. Detecting the phases of awakening and sleep also includes comparing the first state of awakening/sleep to the second state of awakening/sleep, and in the event of a discordance between these states, the response time of the physiological signal processing is modified, in particular by reducing the number of respiratory cycles over which the average MV signal (VE128, VE64) is calculated.
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Citations
20 Claims
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1. An active medical, device, comprising:
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(a) means for measuring a physiological parameter of a patient and delivering a physiological signal;
(b) means for detecting an awakening phase and a sleep phase of the patient, including;
a first comparator means for computing an average value of the measured physiological signal over a first period, and comparing said average with a predetermined physiological threshold; and
(c) means for indicating a first state of the patient as an awakening state in response to the average being greater than said physiological threshold, and as a sleep state otherwise;
(d) means for measuring an activity parameter of the patient and producing a physical signal corresponding to said activity parameter;
(e) second comparator means for comparing the measured physical signal with a predetermined activity threshold; and
(f) means for indicating a second state of the patient as an awakening state in response to said activity signal being greater than said activity threshold, and as a sleep state otherwise;
(g) means for comparing the first state of the patient with the second state of the patient; and
(h) anticipating means for selectively modifying the period of said first comparator means in response to a discordance between the aforementioned first and second states of awakening or sleep. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. An active implantable medical device, comprising:
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(a) a physiological sensor responsive to a physiological parameter of a patient having a first time response and a physiological output signal;
(b) a first a calculator responsive to said physiological output signal, a first period, and a predetermined physiological threshold, said calculator having an output corresponding to an average of successive values of the physiological signal over said period to provide an average physiological signal;
(c) a first state detector indicating a first state of the patient as an awakening state in response to the average physiological signal being greater than the physiological threshold, and as a sleep state otherwise;
(d) a patient activity sensor having a second response time and producing a physical signal output corresponding to an activity of the patient, the second response time being faster than said first response time;
(e) a second state detector for indicating a second state of the patient as an awakening state in response to said activity signal being greater than the activity threshold, and as a sleep state otherwise; and
(f) a comparator responsive to the first state of the patient and the second state of the patient having a first output corresponding to a discordance of said first and second states;
wherein the first calculator response time is modified in response to a discordance between the first and second states of awakening or sleep. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20)
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Specification