Abstract: The fundamental frequency of EIG events is determined directly, without first detecting the events themselves. Use is made of an analysis window containing more than one event (3–5). Techniques (1–8) are utilized which are somewhat similar to those utilized to detect, and estimate pitch in speech processing. The invention is based on two important biological discoveries. The first is that the EIG is generated by a functional pace maker. The second is that the EIG signal is quasi-periodic most of the time. The use of pitch detection algorithms is based on the essentially quasi-periodic nature of the EIG signal. Quasi-periodic means that the intervals between successive events are not exactly identical, but may vary slightly, that the amplitude and shape of successive events may also exhibit some variance.

Abstract: The fundamental frequency of EIG events is determined directly, without first detecting the events themselves. Use is made of an analysis window containing more than one event (3-5). Techniques (1-8) are utilized which are somewhat similar to those utilized to detect, and estimate pitch in speech processing. The invention is based on two important biological discoveries. The first is that the EIG is generated by a functional pace maker. The second is that the EIG signal is quasi-periodic most of the time. The use of pitch detection algorithms is based on the essentially quasi-periodic nature of the EIG signal. Quasi-periodic means that the intervals between successive events are not exactly identical, but may vary slightly, that the amplitude and shape of successive events may also exhibit some variance.

Abstract: A capsule for encapsulating implantable cells for improving the detectability of electrical signals generated by the cells is provided. The capsule includes a low-conductivity (high electrical resistance) membrane and a semi-permeable (low electrical resistance) membrane. The low-conductivity membrane seals around the circumference of the cell mass between the electrical poles of the capsule, and further extends for increasing the electrical resistance between the poles. The semi-permeable membrane enables nutrients and waste materials to flow to and from the cell mass. The semi-permeable membrane enclosed at least one of the poles of the cell mass, and cooperates with the low-conductivity membrane to completely enclose the cell mass. The low-conductivity membrane may enclose one of the poles, if desired. Electrodes are used to detect the electrical signals from the cell mass. Various methods of making the capsule are disclosed.