Cognitive function within a human brain
Methods and apparatus for improving cognitive function within a human. The invention utilizes an implanted device, such as an implantable signal generator or an implantable pump, to affect tissue elements within a Papez circuit of the human brain as well as tissue upstream or downstream from the Papez circuit. The implanted device delivers treatment therapy to thereby improve cognitive function by the human. A sensor may be used to detect various symptoms of the cognitive disorder. A microprocessor algorithm may then analyze the output from the sensor to regulate delivery of the stimulation and/or drug therapy.
1. A method for treating a human cognitive disorder selected from the group consisting of Alzheimer's disease and mild cognitive impairment (MCI) by means of an implantable signal generator and a lead having a proximal end coupled to the signal generator and a distal portion having at least one electrode, the method comprising:
(a) implanting a stimulation portion of the at least one electrode in a an entorhinal cortex of a brain;
(b) coupling the proximal end of the lead implanted electrode to the signal generator; and
(c) treating the cognitive disorder by operating the signal generator to deliver stimulation to the entorhinal cortex.
2. A method as claimed in claim 1 , wherein (c) is performed in relation to a learning task.
3. A method as claimed in claim 2 , wherein the learning task is selected from the group consisting of a memory task, a cognitive task, and a motor task.
4. A method, as claimed in claim 1 , wherein (a) comprises bilaterally implanting at least two electrodes.
5. A method, as claimed in claim 1 , wherein (c) comprises selecting amplitude, width and frequency of stimulation by the electrode.
6. A method, as claimed in claim 1 , wherein (c) comprises operating the signal generator to pulse at a frequency of up to 300 Hertz.
7. A method, as claimed in claim 1 , wherein (c) comprises operating the signal generator to pulse at a pulse amplitude of up to 10 Volts.
8. A method, as claimed in claim 1 , wherein (c) comprises operating the signal generator to pulse at a pulse width of up to 400 μseconds.
9. A method as claimed in claim 1 , further comprising:
(d) sensing a characteristic indicative of an extent of the cognitive disorder and generating a sensor signal; and
(e) regulating operation of the signal generator in response to the sensor signal.
10. A method, as claimed in claim 9 , wherein (d) comprises detecting a neurochemical characteristic of the cognitive disorder.
11. A method, as claimed in claim 9 , wherein (d) comprises detecting a neurochemical characteristic selected from the group consisting of a neurotransmitter level, a pH concentration, an ion concentration, a lactate level, cerebral blood flow, glucose utilization, and oxygen extraction.
12. A method, as claimed in claim 9 , wherein (d) comprises detecting an electrophysiological characteristic of the cognitive disorder.
13. A method, as claimed in claim 12 , wherein (d) comprises detecting an electrophysiological characteristic selected from the group consisting of activity of single neurons, local field potentials, event related potentials, an electroencephalogram, and an electrocorticogram.
14. A method as claimed in claim 9 , wherein (e) comprises executing a control algorithm.
15. A method, as claimed in claim 9 , wherein (e) comprises adjusting at least one parameter of the stimulation, the parameter being selected from the group consisting of amplitude, pulse width and frequency.
16. A method as claimed in claim 1 , further comprising:
(d) sensing a characteristic indicative of an extent of the cognitive disorder and generating a sensor signal; and
(e) if the sensor signal is outside of a predetermined threshold, treating the cognitive disorder by initiating stimulation therapy by the signal generator.
17. A method, as claimed in claim 1 , further comprising:
(d) implanting at least one secondary electrode so that a secondary stimulation portion lies in communication with a predetermined portion of a brain;
(e) coupling the at least one secondary electrode to the signal generator; and
(f) operating the signal generator to stimulate the brain.
18. A method as claimed in claim 1 , further comprising:
(d) implanting at least one secondary catheter so that a secondary stimulation portion lies in communication with tissue elements, wherein the tissue elements are selected from the group consisting of tissue within a Papez circuit of a human brain, tissue within a downstream target of the Papez circuit, and tissue within an upstream input to the Papez circuit:
(e) coupling the at least one secondary catheter to a pump; and
(f) operating the pump to deliver drug to the brain to thereby treat the cognitive disorder in the human.
19. A method as claimed in claim 1 , wherein said cognitive disorder is Alzheimer's disease.
20. A method as claimed in claim 1 , wherein said cognitive disorder is MCI.