A gated electronic switch for stimulation and recording with a single electrode
A circuit design is described for an electronic device which is gate controlled to rapidly switch electrode connections between a stimulator and an amplifier. An integrated switch in the circuit is operated by transistor-transistor logic pulses and will conduct analog signals of up to 15 V amplitude. Electrographic records made using the switch show multi-unit spike discharge after repetitive stimulation of the amygdala in the kindled rat.
Closed-Loop Deep Brain Stimulation for Parkinson’s Disease
Optimal outcomes of deep brain stimulation (DBS) surgery are often an elusive goal. 
 
 
Constant “one-program” stimulation does not reflect the reality of changing clinical symptoms. 
 
 
Closed-loop technology might provide a solution. 
 
 
Closed-loop design will likely integrate multi-sourced sensing data, computed using information from a population database and individual hierarchical paradigms to continuously titrate parameters of stimulation. 
 
 
Proof of principle already exists for the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) primate model and in human Parkinson’s disease (PD) patients. 
 
 
Many elements of such a feedback system have already been developed.
Digital nerve conduction in the carpal tunnel syndrome after mechanical stimulation of the finger.
In 1959 Sears showed that it is possible to record from human digital nerves the afferent volleys evoked by the physiological stimulus of a light tap on the fingernail. Subsequently, Bannister and Sears (1962) used the technique in studying the recovery of nerve conduction in a patient with acute idiopathic polyneuritis. This method of initiating volleys by stimulating peripheral mechanoreceptors has been employed in the present investigation to determine the conduction velocity of volleys in the digital nerves of control subjects and of patients with the carpal tunnel syndrome. It is known that in this condition there is slowing of motor conduction (Simpson, 1956; Thomas, 1960) and of sensory conduction (Gilliatt and Sears, 1958) across the compressive lesion at the wrist, but measurements of the conduction velocity in the digital nerves distal to the lesion have not previously been made. A brief account of this work has already been published (McLeod, 1965).