A method of characterizing motor function of a user by analyzing an input by the user to a user interface of at least one computing device, the method comprising: receiving a sequence of keystroke events indicating that the user pressed at least a portion of the user interface over a time duration; characterized by: determining, by at least one processor, a plurality of probability distributions of keystroke event intervals over at least some of the time duration, wherein each probability distribution of the plurality of probability distributions corresponds to a portion of the time duration, the plurality of probability distributions of keystroke event intervals comprises a first probability distribution relating to keystroke events included in a first portion of the time duration and a second probability distribution relating to keystroke events included in a second portion of the time duration, wherein determining a probability distribution of the plurality of distributions comprises identifying time intervals between keystroke events that occur within a corresponding portion of the time duration; and determining a stability of the motor function of the user at least in part by analyzing at least the first probability distribution and the second probability distribution to determine variation of keystroke event intervals over the time duration, wherein analyzing at least the first probability distribution and the second probability distribution comprises: calculating at least one feature of the first and second probability distributions; and determining variation of the at least one feature being a distribution width between the first and second probability distributions. receiving a sequence of keystroke events indicating that the user pressed at least a portion of the user interface over a time duration; characterized by: determining, by at least one processor, a plurality of probability distributions of keystroke event intervals over at least some of the time duration, wherein each probability distribution of the plurality of probability distributions corresponds to a portion of the time duration, the plurality of probability distributions of keystroke event intervals comprises a first probability distribution relating to keystroke events included in a first portion of the time duration and a second probability distribution relating to keystroke events included in a second portion of the time duration, wherein determining a probability distribution of the plurality of distributions comprises identifying time intervals between keystroke events that occur within a corresponding portion of the time duration; and determining a stability of the motor function of the user at least in part by analyzing at least the first probability distribution and the second probability distribution to determine variation of keystroke event intervals over the time duration, wherein analyzing at least the first probability distribution and the second probability distribution comprises: calculating at least one feature of the first and second probability distributions; and determining variation of the at least one feature being a distribution width between the first and second probability distributions. determining, by at least one processor, a plurality of probability distributions of keystroke event intervals over at least some of the time duration, wherein each probability distribution of the plurality of probability distributions corresponds to a portion of the time duration, the plurality of probability distributions of keystroke event intervals comprises a first probability distribution relating to keystroke events included in a first portion of the time duration and a second probability distribution relating to keystroke events included in a second portion of the time duration, wherein determining a probability distribution of the plurality of distributions comprises identifying time intervals between keystroke events that occur within a corresponding portion of the time duration; and determining a stability of the motor function of the user at least in part by analyzing at least the first probability distribution and the second probability distribution to determine variation of keystroke event intervals over the time duration, wherein analyzing at least the first probability distribution and the second probability distribution comprises: calculating at least one feature of the first and second probability distributions; and determining variation of the at least one feature being a distribution width between the first and second probability distributions. calculating at least one feature of the first and second probability distributions; and determining variation of the at least one feature being a distribution width between the first and second probability distributions.