<unk> , in general, can cause tissue damage or even death if misused. The most common problems arising from<unk>  tend to be burns from lack of sufficiently wide surface contact, i.e. bad contact, between the electrode and the skin's surface. Even at relatively low current and voltage, there is also risk of interference with normal heart function (potentially including cardiac arrest), and this risk is higher for those who use an artificial pacemaker or similar device or who have heart conditions. Because of this, it is not advisable to place the electrical contacts in such a way that current passes through the chest cavity. The international standard on the basic safety of medical nerve and muscle stimulators advises "that stimulation should not be applied across or through the head, directly on the eyes, covering the mouth, on the front of the neck, (especially the carotid sinus), or from electrodes placed on the chest and the upper back or crossing over the heart". The standard also notes that "any electrodes that have current densities exceeding 2 mA/cm² may require the special attention of the operator". It imposes the following limits on the output parameters of stimulators (for therapeutic purposes): * with a load resistance of 500 Ω, the output current shall not exceed *80 mA at DC *50 mA below 400 Hz pulse frequency *80 mA at 400–1500 Hz *100 mA above 1500 Hz * for pulse durations less than 0.1 s, the pulse energy into a 500 Ω load shall not exceed 300 mJ per pulse, for longer pulses the above DC limit applies * the output shall not exceed a peak voltage of 500 V when measured under open-circuit condition<unk>  devices should avoid DC currents entirely, in order to avoid electrolytic effects. This is usually achieved through “biphasic” waveforms, in which each positive current pulse is followed by an equivalent negative current pulse. Devices with multiple channels (e.g. for several users or body regions) should have a small pulse isolation transformer for galvanic isolation in each channel, such that currents cannot flow across the body between channels. Pulse frequency, duration and amplitude should be selected to achieve the desired stimulation with the least amount of power delivered into the body, for example avoiding current during the refractory period after each action potential, where neurons do not respond to stimuli. Typical<unk>  devices use pulse frequencies in the range 300–3000 Hz, where skin nerves are most sensitive. A few cases of accidental death as a result of autoerotic<unk>  have been reported in the forensic science literature; the cases reported involved mains-powered, self-made devices, with current passing through the chest intentionally (usually via nipple stimulation) or unintentionally (for instance, touching an energized part with a hand). In one case reported in the press, a man from York, Pennsylvania was sentenced to 20–40 years in prison for third-degree murder and reckless endangerment after killing his wife with<unk>  to her nipples directly from a power strip plugged into the mains.
Erotic electrostimulation
Fundal massage
Laser hair removal
Low-level laser therapy
Intermittent photic stimulation
GreenLight Laser Therapy
Topical steroid withdrawal
Small incision lenticule extraction