Biomedical Engineering Reference
In-Depth Information
Fig. 4.63.
Upper:
changes with time in the pressure that were applied to the finger
(
upper line
), and those in the intensities of the evoked pressure sensations felt by
the subjects.
Lower:
changes with time in the pressure applied to the conductive
rubber (
upper line
) and those in the subjective intensities of the evoked sensation,
as described by the subject (
lower line
) when the pressure was transferred to the
subject by the system
In both cases, although some motion delay can be observed in the chart,
similar changes in the evoked sensations were observed, corresponding to the
changes in the pressure applied to the hand (former case) or to the pressure-
conductive rubber (latter case); furthermore, stimuli detected by the sensors
of an artificial arm system were thought to be successfully conveyed to the
subjects via this artificial arm system, which produced the same somatic
sensation as the original stimuli and with corresponding magnitude.
However, several obstacles still remain to be overcome in order to improve
this prototype system so that it can be used in actual clinical cases.
The main problem lies in the development of a multi-channel microelec-
trode that is capable of connecting each nerve fiber to an electrical signal
line from external devices, so as to enable actual clinical use. Basically, the
number of lines that can be connected using the microneurographic techni-
que is limited to at most two or three. However, in order to connect all fibers
contained in a peripheral nerve to each corresponding electrical signal line,
it will be necessary for the electrode to have a minimum of more than 10,000
channels.
