A stimulator for stimulating the leg or other parts of the body e.g. the leg in a patient with drop foot is provided, the stimulator being controlled by e.g a
foot switch but being reliable in use and therefore commanding acceptance by users. The
foot switch has to work in adverse environmental conditions and is subject to repeated use so that its characteristics vary with time. The invention provides a functional
electrical stimulator for attachment to the leg that has adaptive characteristics and comprises first and second electrodes for attachment to the leg to apply an electrical stimulus, a
foot switch for sensing foot rise or foot strike, a circuit responsive to said foot switch for generating stimulation pulses; and means forming part of said circuit for responding to changes in the resistance characteristics of said switch means by adjusting a corresponding response threshold of said circuit.The invention also provides a two-channel stimulator that offers various possibilities for controlling the signals to be supplied to different
muscle groups. For example, means may be provided defining a
signal pathway between the first and second channels so that the supply of stimulation pulses in one of said first and second channels can be controlled by the state of switch means associated with the other of said first and second channels. In a further embodiment means defining a
signal pathway between the first and second channels is arranged so that the supply of stimulation pulses in one of said first and second channels can be controlled by the state of activity of the other of said first and second channels. In a yet further embodiment the first channel has means arranged to cause the stimulation pulses to time-out after a predetermined period and the second channel having no or disabled timing means so that supply of stimulation pulses is continuous in a predetermined state of limb position responsive switch means associated with that channel. The two-channel stimulator can be used e.g., to treat bilateral
dropped foot.