kaap 428 exam 2

What is motor performance?

what we actually measure when a person performs a skill

types of motor performance

outcome score and process measures

outcome measures

indicate the outcome of performing a skill

outcome measures examples

accuracy, time/speed, magnitude

how do we measure error

the criteria can be a specific target in space, or time

dichotomy

hit or miss

absolute error definition

the absolute difference in relevant units between the criterion and the performance outcome (single dimension)

radial error definition

absolute error for two dimensions

constant error definition

represents magnitude of error in a specific direction

variable error definition

an index of how much variability there is in the accuracy of performance

variable error is like

consistency

absolute error and constant error is like

accuracy

root mean square error

error between a participant's displacement (position) curve and a criterion (ideal curve)

reaction time

interval between the onset of a signal or stimulus, to the initiation of a response

simple reaction time

there is one stimulus and that elicits a response (hearing a gun go off signals you to start running the race)

choice reaction time

there are multiple stimuli that elicit different responses and you have to choose the correct response based on the stimuli (each color of a stoplight represents a different response when driving) (3:3 stimuli to response)

discrimination reaction time

there are multiple stimuli and you have to react to the correct stimuli using the best response (determining the pitcher is throwing a fastball as opposed to a curve ball and hitting responsively) (3:1 stimuli to response)

movement time

the interval from the initiation of the response to the completion of the movement

response time

the sum of reaction time and movement time. from the onset of a go signal to the completion of the movement

EMG

measures the electrical activity in muscle. electrodes are attached to the skin superficial to the muscle belly

process measures vs outcome measures

outcome measures do not tell us how a result was achieved. to understand what underlies performance, we need process measures

kinematics definition

measures which describe motion, without regard to the cause of that motion

kinetics definition

measurements of the forces which cause motion

force

push or pull on an object; product of an object's mass and acceleration

torque

angular force directed around an axis of rotation; product of force and perpendicular distance to the axis

momentum

product of an object's mass and velocity

is it an objective measure?

a measure is objective if it can be employed consistently by different people. it is also objective if the measurement scale is appropriate

is it a valid measure?

this refers to whether a test measures what it is supposed to measure. does your measure have construct validity? magnitude measures almost always do

Is it a reliable measure?

is the measurement repeatable? Deviations in a way a test is performed can result in markedly different results

improving your tests' objectivity, reliability, and validity

consider the purpose of the skill

keep the test environment consistent

document your methodology

standardize measures

don't test yourself

step 1 SM

develop a testable research question

step 2 SM

formulate hypotheses

step 3 SM

operationally define independent and dependent variables

step 4 SM

design study to test research

step 5 SM

observe behavior and gather data

step 6 SM

analyze and interpret results of the study

speed of movement

average velocity across a single movement

average speed

movement time / speed

effect of vision on movement accuracy

accuracy is better with eyes open

vision advantages disappear at very fast speeds

accuracy is pretty good without vision

speed has little impact on the eyes closed condition

speed accuracy trade-off

decreasing speed improves accuracy, or conversely, increasing speed decreases accuracy

Fitts' Law

curves of the relationship between Movement Time and Distance or Movement Time and Width were not a straight line (proportional)

MT equation

a + b log2 (2D/W)

D

distance of movement to an object

W

width of target

index of difficulty

log2 (2D/W)

accuracy requirements on kinematics

speed is reduced when greater accuracy is needed

people produce more force with larger targets

speed profile can have fluctuations in the deceleration phase

submovements can be indicative of disordered motor control

speed/accuracy

peak speed is lower (movement is slower) when the target is smaller (requires more accuracy)

force/targets

more precise movements require a softer "touch"

main movement

movement into the vicinity of the target

submovements

movement accurately into the target

PD and submovements

patients show many submovements in fast and slow movement conditions

woodworth's two-component hypothesis

phase 1: initial phase

phase 2: homing in phase

initial phase

get in the vicinity of the target

homing in phase

refine your location to contact the target

why do movements to smaller targets take longer

they involve more corrective submovements

the execution is slower whether submovements occur or not

timing matching tasks

require you to generate a particular MT

time matching error

actual MT - required MT

intercepting a moving target

requires temporal accuracy

capture tasks

make contact and "capture" the object

hitting tasks

make contact and transfer momentum

pre-programming hypothesis

prior to movement, we predict the duration of the movement

timing and moving targets

visual information plays an important role in intercepting moving targets

what is memory

information that must be retained and accessed later

motor memory

the persistence of the acquired capability for motor performance

short term memory definition

temporary scratch pad for information

long term memory definition

long-term repository for memories/information

declarative (explicit)

facts and events

non-declarative (procedural) "implicit"

skills and habits

sensorimotor memories

non-declarative memory

declarative memories brain areas

hippocampus

cerebral cortex

amygdala

hippocampus

memory encoding and storage

cerebral cortex

sensory perception and cognition

amygdala

traumatic, unconscious memories

non-declarative memory brain areas

basal ganglia

cerebellum

basal ganglia

stimulus-response habits

cerebellum

storage of the internal model

long-term potentiation

memories are groups of neurons that fire together in the same pattern each time they become activated

what happens to the brain in AD

development of amyloid plaques

development of neurofibrillary tangles

leads to loss of neurons

grey matter shrinks

overall brain volume decreases

apraxia

person cannot produce movement from verbal command

agnosia

person can produce a movement but cannot name it

retention

the information that we remember