ORKOrderedTask Class Reference

Inherits from	NSObject
Conforms to	NSCopying NSSecureCoding ORKTask
Declared in	ORKOrderedTask.h

The ORKOrderedTask class implements all the methods in the ORKTask protocol and represents a task that assumes a fixed order for its steps.

In the ResearchKit framework, any simple sequential task, such as a survey or an active task, can be represented as an ordered task.

If you want further custom conditional behaviors in a task, it can be easier to subclass ORKOrderedTask or ORKNavigableOrderedTask and override particular ORKTask methods than it is to implement the ORKTask protocol directly. Override the methods stepAfterStep:withResult: and stepBeforeStep:withResult:, and call super for all other methods.

Initializers

`– initWithIdentifier:steps:`

Returns an initialized ordered task using the specified identifier and array of steps.

- (instancetype)initWithIdentifier:(NSString *)identifier steps:(nullable NSArray<ORKStep*> *)steps

Parameters

`identifier`	The unique identifier for the task.
`steps`	An array of `ORKStep` objects in the order in which they should be presented.

Return Value

An initialized ordered task.

Declared In

ORKOrderedTask.h

`– initWithCoder:`

Returns an ordered task initialized from data in the given unarchiver.

- (instancetype)initWithCoder:(NSCoder *)aDecoder

Parameters

`aDecoder`	The coder from which to initialize the ordered task.

Return Value

An initialized ordered task.

Discussion

An ordered task can be serialized and deserialized with NSKeyedArchiver. Note that this serialization includes strings that might need to be localized.

Declared In

ORKOrderedTask.h

Properties

`steps`

The array of steps in the task. (read-only)

@property (nonatomic, copy, readonly) NSArray<ORKStep*> *steps

Discussion

Each element in the array must be a subclass of ORKStep. The associated task view controller presents the steps in array order.

Declared In

ORKOrderedTask.h

`progressLabelColor`

Color property of the progress label. Default is black.

@property (nonatomic) UIColor *progressLabelColor

Declared In

ORKOrderedTask.h

`– copyWithSteps:`

Return a mutated copy of self with the steps included in the given array.

- (instancetype)copyWithSteps:(NSArray<ORKStep*> *)steps

Parameters

`steps`	An array of `ORKStep` objects in the order in which they should be presented.

Return Value

An initialized ordered task.

Discussion

This method is intended to allow for mutating an ordered task (or subclass) while retaining the original class and properties that may not be publicly exposed, but with a mutated set of steps. An example of where this might be useful is if before performing an ORKPredefinedActiveTask, the app needed to query the participant about medications, diet or sleep. The app would need to mutate the steps in order to insert their own steps. While an ORKOrderedTask could then be created with the same identifier and the new steps, subclass information such rules on an ORKNavigableOrderedTask would be lost.

Declared In

ORKOrderedTask.h

`– indexOfStep:`

Find the index of a given step.

- (NSUInteger)indexOfStep:(ORKStep *)step

Parameters

`step`	The step to look for

Return Value

The index position of the step (or NSNotFound if not found)

Declared In

ORKOrderedTask.h

ORKPredefinedActiveTask Methods

`+ amslerGridTaskWithIdentifier:intendedUseDescription:options:`

Returns a predefined Amsler Grid task that helps in detecting problems in user’s vision.

+ (ORKNavigableOrderedTask *)amslerGridTaskWithIdentifier:(NSString *)identifier intendedUseDescription:(nullable NSString *)intendedUseDescription options:(ORKPredefinedTaskOption)options

Parameters

`identifier`	The task identifier to use for this task, appropriate to the study.
`intendedUseDescription`	A localized string describing the intended use of the data collected. If the value of this parameter is `nil`, the default localized text is displayed.
`options`	Options that affect the features of the predefined task.

Discussion

In an Amsler Grid task, the participant is shown a square grid. The participant is asked to mark the areas where they notice disctortions in the grid.

Data collected by the task is in the form of an ORKAmslerGridResult object.

Declared In

ORKOrderedTask+ORKPredefinedActiveTask.h

`+ holePegTestTaskWithIdentifier:intendedUseDescription:dominantHand:numberOfPegs:threshold:rotated:timeLimit:options:`

Returns a predefined task that measures the upper extremity function.

+ (ORKNavigableOrderedTask *)holePegTestTaskWithIdentifier:(NSString *)identifier intendedUseDescription:(nullable NSString *)intendedUseDescription dominantHand:(ORKBodySagittal)dominantHand numberOfPegs:(int)numberOfPegs threshold:(double)threshold rotated:(BOOL)rotated timeLimit:(NSTimeInterval)timeLimit options:(ORKPredefinedTaskOption)options

Parameters

`identifier`	The task identifier to use for this task, appropriate to the study.
`intendedUseDescription`	A localized string describing the intended use of the data collected. If the value of this parameter is `nil`, the default localized text will be displayed.
`dominantHand`	The participant dominant hand that will be tested first.
`numberOfPegs`	The number of pegs to place in the pegboard.
`threshold`	The threshold value used for the detection area.
`rotated`	A test variant that also requires peg rotation.
`timeLimit`	The duration allowed to validate the peg position.
`options`	Options that affect the features of the predefined task.

Return Value

An active hole peg test task that can be presented with an ORKTaskViewController object.

Discussion

In a hole peg test task, the participant is asked to fill holes with pegs.

A hole peg test task can be used to assess arm and hand function, especially in patients with severe disability.

Data collected in this task is in the form of an ORKHolePegTestResult object.

Declared In

ORKOrderedTask+ORKPredefinedActiveTask.h

`+ fitnessCheckTaskWithIdentifier:intendedUseDescription:walkDuration:restDuration:options:`

Returns a predefined task that consists of a fitness check.

+ (ORKOrderedTask *)fitnessCheckTaskWithIdentifier:(NSString *)identifier intendedUseDescription:(nullable NSString *)intendedUseDescription walkDuration:(NSTimeInterval)walkDuration restDuration:(NSTimeInterval)restDuration options:(ORKPredefinedTaskOption)options

Parameters

`identifier`	The task identifier to use for this task, appropriate to the study.
`intendedUseDescription`	A localized string describing the intended use of the data collected. If the value of this parameter is `nil`, the default localized text is displayed.
`walkDuration`	The duration of the walk (the maximum is 10 minutes).
`restDuration`	The duration of the post walk rest period.
`options`	Options that affect the features of the predefined task.

Return Value

An active fitness check task that can be presented with an ORKTaskViewController object.

Discussion

In a fitness check task, the participant is asked to walk for a specified duration (typically several minutes). During this period, various sensor data is collected and returned by the task view controller’s delegate. Sensor data can include accelerometer, device motion, pedometer, location, and heart rate data where available.

At the conclusion of the walk, if heart rate data is available, the participant is asked to sit down and rest for a period. Data collection continues during this period.

By default, the task includes an instruction step that explains what the user needs to do during the task, but this can be excluded with ORKPredefinedTaskOptionExcludeInstructions.

Data collected from this task can be used to compute measures of general fitness.

Declared In

ORKOrderedTask+ORKPredefinedActiveTask.h

`+ shortWalkTaskWithIdentifier:intendedUseDescription:numberOfStepsPerLeg:restDuration:options:`

Returns a predefined task that consists of a short walk.

+ (ORKOrderedTask *)shortWalkTaskWithIdentifier:(NSString *)identifier intendedUseDescription:(nullable NSString *)intendedUseDescription numberOfStepsPerLeg:(NSInteger)numberOfStepsPerLeg restDuration:(NSTimeInterval)restDuration options:(ORKPredefinedTaskOption)options

Parameters

`identifier`	The task identifier to use for this task, appropriate to the study.
`intendedUseDescription`	A localized string describing the intended use of the data collected. If the value of this parameter is `nil`, the default localized text is displayed.
`numberOfStepsPerLeg`	The number of steps the participant is asked to walk. If the pedometer is unavailable, a distance is suggested and a suitable count down timer is displayed for each leg of the walk.
`restDuration`	The duration of the rest period. When the value of this parameter is nonzero, the user is asked to stand still for the specified rest period after the turn sequence has been completed, and baseline data is collected.
`options`	Options that affect the features of the predefined task.

Return Value

An active short walk task that can be presented with an ORKTaskViewController object.

Discussion

In a short walk task, the participant is asked to walk a short distance, which may be indoors. Typical uses of the resulting data are to assess stride length, smoothness, sway, or other aspects of the participant’s gait.

The presentation of the short walk task differs from the fitness check task in that the distance is replaced by the number of steps taken, and the walk is split into a series of legs. After each leg, the user is asked to turn and reverse direction.

The data collected by this task can include accelerometer, device motion, and pedometer data.

Declared In

ORKOrderedTask+ORKPredefinedActiveTask.h

`+ walkBackAndForthTaskWithIdentifier:intendedUseDescription:walkDuration:restDuration:options:`

Returns a predefined task that consists of a short walk back and forth.

+ (ORKOrderedTask *)walkBackAndForthTaskWithIdentifier:(NSString *)identifier intendedUseDescription:(nullable NSString *)intendedUseDescription walkDuration:(NSTimeInterval)walkDuration restDuration:(NSTimeInterval)restDuration options:(ORKPredefinedTaskOption)options

Parameters

`identifier`	The task identifier to use for this task, appropriate to the study.
`intendedUseDescription`	A localized string describing the intended use of the data collected. If the value of this parameter is `nil`, the default localized text is displayed.
`walkDuration`	The duration of the walking period.
`restDuration`	The duration of the rest period. When the value of this parameter is nonzero, the user is asked to stand still for the specified rest period after the turn sequence has been completed, and baseline data is collected.
`options`	Options that affect the features of the predefined task.

Return Value

An active short walk task that can be presented with an ORKTaskViewController object.

Discussion

The presentation of the back and forth walk task differs from the short walk in that the participant is asked to walk back and forth rather than walking in a straight line for a certain number of steps.

The participant is then asked to turn in a full circle and then stand still.

This task is intended to allow the participant to walk in a confined space where the participant does not have access to a long hallway to walk in a continuous straight line. Additionally, by asking the participant to turn in a full circle and then stand still, the activity can access balance and concentration.

The data collected by this task can include accelerometer, device motion, and pedometer data.

Declared In

ORKOrderedTask+ORKPredefinedActiveTask.h

`+ kneeRangeOfMotionTaskWithIdentifier:limbOption:intendedUseDescription:options:`

The knee range of motion task returns a task that measures the range of motion for either a left or right knee.

+ (ORKOrderedTask *)kneeRangeOfMotionTaskWithIdentifier:(NSString *)identifier limbOption:(ORKPredefinedTaskLimbOption)limbOption intendedUseDescription:(nullable NSString *)intendedUseDescription options:(ORKPredefinedTaskOption)options

Parameters

`identifier`	The task identifier to use for this task, appropriate to the study.
`limbOption`	Which knee is being measured.
`intendedUseDescription`	A localized string describing the intended use of the data collected. If the value of this parameter is `nil`, default localized text is used.
`options`	Options that affect the features of the predefined task.

Declared In

ORKOrderedTask+ORKPredefinedActiveTask.h

`+ shoulderRangeOfMotionTaskWithIdentifier:limbOption:intendedUseDescription:options:`

The shoulder range of motion task returns a task that measures the range of motion for either a left or right shoulder.

+ (ORKOrderedTask *)shoulderRangeOfMotionTaskWithIdentifier:(NSString *)identifier limbOption:(ORKPredefinedTaskLimbOption)limbOption intendedUseDescription:(nullable NSString *)intendedUseDescription options:(ORKPredefinedTaskOption)options

Parameters

`identifier`	The task identifier to use for this task, appropriate to the study.
`limbOption`	Which shoulder is being measured.
`intendedUseDescription`	A localized string describing the intended use of the data collected. If the value of this parameter is `nil`, default localized text is used.
`options`	Options that affect the features of the predefined task.

Declared In

ORKOrderedTask+ORKPredefinedActiveTask.h

`+ audioTaskWithIdentifier:intendedUseDescription:speechInstruction:shortSpeechInstruction:duration:recordingSettings:checkAudioLevel:options:`

Returns a predefined task that enables an audio recording WITH a check of the audio level.

+ (ORKNavigableOrderedTask *)audioTaskWithIdentifier:(NSString *)identifier intendedUseDescription:(nullable NSString *)intendedUseDescription speechInstruction:(nullable NSString *)speechInstruction shortSpeechInstruction:(nullable NSString *)shortSpeechInstruction duration:(NSTimeInterval)duration recordingSettings:(nullable NSDictionary *)recordingSettings checkAudioLevel:(BOOL)checkAudioLevel options:(ORKPredefinedTaskOption)options

Parameters

`identifier`	The task identifier to use for this task, appropriate to the study.
`intendedUseDescription`	A localized string describing the intended use of the data collected. If the value of this parameter is `nil`, default localized text is used.
`speechInstruction`	Instructional content describing what the user needs to do when recording begins. If the value of this parameter is `nil`, default localized text is used.
`shortSpeechInstruction`	Instructional content shown during audio recording. If the value of this parameter is `nil`, default localized text is used.
`duration`	The length of the count down timer that runs while audio data is collected.
`recordingSettings`	See “AV Foundation Audio Settings Constants” for possible values.
`checkAudioLevel`	If `YES` then add navigational rules to check the background noise level.
`options`	Options that affect the features of the predefined task.

Return Value

An active audio task that can be presented with an ORKTaskViewController object.

Discussion

In an audio recording task, the participant is asked to make some kind of sound with their voice, and the audio data is collected.

An audio task can be used to measure properties of the user’s voice, such as frequency range, or the ability to pronounce certain sounds.

If checkAudioLevel == YES then a navigation rule is added to do a simple check of the background noise level. If the background noise is too loud, then the participant is instructed to move to a quieter location before trying again.

Data collected in this task consists of audio information.

Declared In

ORKOrderedTask+ORKPredefinedActiveTask.h

`+ twoFingerTappingIntervalTaskWithIdentifier:intendedUseDescription:duration:handOptions:options:`

Returns a predefined task that consists of two finger tapping (Optionally with a hand specified)

+ (ORKOrderedTask *)twoFingerTappingIntervalTaskWithIdentifier:(NSString *)identifier intendedUseDescription:(nullable NSString *)intendedUseDescription duration:(NSTimeInterval)duration handOptions:(ORKPredefinedTaskHandOption)handOptions options:(ORKPredefinedTaskOption)options

Parameters

`identifier`	The task identifier to use for this task, appropriate to the study.
`intendedUseDescription`	A localized string describing the intended use of the data collected. If the value of this parameter is `nil`, the default localized text will be displayed.
`duration`	The length of the count down timer that runs while touch data is collected.
`handOptions`	Options for determining which hand(s) to test.
`options`	Options that affect the features of the predefined task.

Return Value

An active two finger tapping task that can be presented with an ORKTaskViewController object.

Discussion

In a two finger tapping task, the participant is asked to rhythmically and alternately tap two targets on the device screen.

A two finger tapping task can be used to assess basic motor capabilities including speed, accuracy, and rhythm.

Data collected in this task includes touch activity and accelerometer information.

Declared In

ORKOrderedTask+ORKPredefinedActiveTask.h

`+ spatialSpanMemoryTaskWithIdentifier:intendedUseDescription:initialSpan:minimumSpan:maximumSpan:playSpeed:maximumTests:maximumConsecutiveFailures:customTargetImage:customTargetPluralName:requireReversal:options:`

Returns a predefined task that tests spatial span memory.

+ (ORKOrderedTask *)spatialSpanMemoryTaskWithIdentifier:(NSString *)identifier intendedUseDescription:(nullable NSString *)intendedUseDescription initialSpan:(NSInteger)initialSpan minimumSpan:(NSInteger)minimumSpan maximumSpan:(NSInteger)maximumSpan playSpeed:(NSTimeInterval)playSpeed maximumTests:(NSInteger)maximumTests maximumConsecutiveFailures:(NSInteger)maximumConsecutiveFailures customTargetImage:(nullable UIImage *)customTargetImage customTargetPluralName:(nullable NSString *)customTargetPluralName requireReversal:(BOOL)requireReversal options:(ORKPredefinedTaskOption)options

Parameters

`identifier`	The task identifier to use for this task, appropriate to the study.
`intendedUseDescription`	A localized string describing the intended use of the data collected. If the value of this parameter is `nil`, the default localized text is displayed.
`initialSpan`	The sequence length of the initial memory pattern.
`minimumSpan`	The minimum pattern sequence length.
`maximumSpan`	The maximum pattern sequence length.
`playSpeed`	The time per sequence item; a smaller value means faster sequence play.
`maximumTests`	The maximum number of rounds to conduct.
`maximumConsecutiveFailures`	The maximum number of consecutive failures the user can make before the task is terminated.
`customTargetImage`	The image to use for the task. By default, and if the value of this parameter is `nil`, the image is a flower. To supply a custom image, create a template image to which iOS adds the tint color.
`customTargetPluralName`	The name associated with `customTargetImage`; by default, the value of this parameter is @“flowers”.
`requireReversal`	A Boolean value that indicates whether to require the user to tap the sequence in reverse order.
`options`	Options that affect the features of the predefined task.

Return Value

An active spatial span memory task that can be presented with an ORKTaskViewController object.

Discussion

In a spatial span memory task, the participant is asked to repeat pattern sequences of increasing length in a game-like environment. You can use this task to assess visuospatial memory and executive function.

In each round of the task, an array of target images are shown in a grid (by default, the images are flowers). The round consists of a demonstration phase and an interactive phase. In the demonstration phase, some of the flowers change color in a specific sequence. After the demonstration, the user is asked to tap the flowers in the same sequence for the interactive phase.

The span (that is, the length of the pattern sequence) is automatically varied during the task, increasing after users succeed and decreasing after they fail, within the range specified by minimum and maximum values that you specify. You can also customize the speed of sequence playback and the shape of the tap target.

A spatial span memory task finishes when the user has either completed the maximum number of tests or made the maximum number of errors.

Data collected by the task is in the form of an ORKSpatialSpanMemoryResult object.

Declared In

ORKOrderedTask+ORKPredefinedActiveTask.h

`+ stroopTaskWithIdentifier:intendedUseDescription:numberOfAttempts:options:`

Returns a predefined Stroop task that tests participants selective attention and cognitive flexibility.

+ (ORKOrderedTask *)stroopTaskWithIdentifier:(NSString *)identifier intendedUseDescription:(nullable NSString *)intendedUseDescription numberOfAttempts:(NSInteger)numberOfAttempts options:(ORKPredefinedTaskOption)options

Parameters

`identifier`	The task identifier to use for this task, appropriate to the study.
`intendedUseDescription`	A localized string describing the intended use of the data collected. If the value of this parameter is `nil`, the default localized text is displayed.
`numberOfAttempts`	Total number of stroop questions to include in the task.
`options`	Options that affect the features of the predefined task.

Discussion

In a stroop task, the participant is shown a text. The text is a name of a color, but the text is printed in a color that may or may not be denoted by the name. In each attempt of the task, the participant has to press the button that corresponds to the first letter of the color in which the text is printed. The participant has to ignore the name of the color written in the text, but respond based on the color of the text.

A stroop task finishes when the user has completed all the attempts, irrespective of correct or incorrect answers.

Data collected by the task is in the form of an ORKStroopResult object.

Declared In

ORKOrderedTask+ORKPredefinedActiveTask.h

`+ speechRecognitionTaskWithIdentifier:intendedUseDescription:speechRecognizerLocale:speechRecognitionImage:speechRecognitionText:shouldHideTranscript:allowsEdittingTranscript:options:`

Returns a predefined Speech Recognition task that transcribes participant’s speech.

+ (ORKOrderedTask *)speechRecognitionTaskWithIdentifier:(NSString *)identifier intendedUseDescription:(nullable NSString *)intendedUseDescription speechRecognizerLocale:(ORKSpeechRecognizerLocale)speechRecognizerLocale speechRecognitionImage:(nullable UIImage *)speechRecognitionImage speechRecognitionText:(nullable NSString *)speechRecognitionText shouldHideTranscript:(BOOL)shouldHideTranscript allowsEdittingTranscript:(BOOL)allowsEdittingTranscript options:(ORKPredefinedTaskOption)options

Parameters

`identifier`	The task identifier to use for this task, appropriate to the study.
`intendedUseDescription`	A localized string describing the intended use of the data collected. If the value of this parameter is `nil`, the default localized text is displayed.
`speechRecognizerLocale`	An enum that represents the locale to be used by speech recognition API.
`speechRecognitionImage`	The image shown to the participant.
`speechRecognitionText`	The text shown to the participant.
`shouldHideTranscript`	The boolean value used to show or hide the transcription from the user.
`allowsEdittingTranscript`	The boolean value used to present step that allows editting transcription.
`options`	Options that affect the features of the predefined task.

Discussion

In a Speech Recognition task, the participant is shown a text or image or both. The participant has to read the text aloud, or describe the image.

A Speech Recognition task finishes when the user presses the Stop Recording button.

Data collected by the task is in the form of an ORKSpeechRecognitionResult object.

Declared In

ORKOrderedTask+ORKPredefinedActiveTask.h

`+ speechInNoiseTaskWithIdentifier:intendedUseDescription:options:`

Returns a predefined task that tests speech audiometry.

+ (ORKOrderedTask *)speechInNoiseTaskWithIdentifier:(NSString *)identifier intendedUseDescription:(nullable NSString *)intendedUseDescription options:(ORKPredefinedTaskOption)options

Parameters

`identifier`	The task identifier to use for this task, appropriate to the study.
`intendedUseDescription`	A localized string describing the intended use of the data collected. If the value of this parameter is `nil`, default localized text is used.
`options`	Options that affect the features of the predefined task.

Return Value

An active speech in noise task that can be presented with an ORKTaskViewController object.

Discussion

In a speech in noise task, the participant is asked to listen to some sentences mixed with background noise at varying signal to noise ratio (SNR).

You can use a speech in noise task to measure the speech reception threshold (SRT) of an individual.

Declared In

ORKOrderedTask+ORKPredefinedActiveTask.h

`+ toneAudiometryTaskWithIdentifier:intendedUseDescription:speechInstruction:shortSpeechInstruction:toneDuration:options:`

Returns a predefined task that tests tone audiometry.

+ (ORKOrderedTask *)toneAudiometryTaskWithIdentifier:(NSString *)identifier intendedUseDescription:(nullable NSString *)intendedUseDescription speechInstruction:(nullable NSString *)speechInstruction shortSpeechInstruction:(nullable NSString *)shortSpeechInstruction toneDuration:(NSTimeInterval)toneDuration options:(ORKPredefinedTaskOption)options

Parameters

`identifier`	The task identifier to use for this task, appropriate to the study.
`intendedUseDescription`	A localized string describing the intended use of the data collected. If the value of this parameter is `nil`, default localized text is used.
`speechInstruction`	Instructional content describing what the user needs to do when recording begins. If the value of this parameter is `nil`, default localized text is used.
`shortSpeechInstruction`	Instructional content shown during audio recording. If the value of this parameter is `nil`, default localized text is used.
`toneDuration`	The maximum length of the duration for each tone (each tone can be interrupted sooner, after the participant presses the main button).
`options`	Options that affect the features of the predefined task.

Return Value

An active tone audiometry task that can be presented with an ORKTaskViewController object.

Discussion

In a tone audiometry task, the participant is asked to listen to some tones with different audio frequencies, playing on different channels (left and right), with the volume being progressively increased until the participant taps a button.

You can use a tone audiometry task to measure properties of the user’s hearing, based on their reaction to a wide range of frequencies.

Data collected in this task consists of audio signal amplitude for specific frequencies and channels.

Declared In

ORKOrderedTask+ORKPredefinedActiveTask.h

`+ dBHLToneAudiometryTaskWithIdentifier:intendedUseDescription:options:`

Returns a predefined task that tests dBHL tone audiometry.

+ (ORKOrderedTask *)dBHLToneAudiometryTaskWithIdentifier:(NSString *)identifier intendedUseDescription:(nullable NSString *)intendedUseDescription options:(ORKPredefinedTaskOption)options

Parameters

`identifier`	The task identifier to use for this task, appropriate to the study.
`intendedUseDescription`	A localized string describing the intended use of the data collected. If the value of this parameter is `nil`, default localized text is used.
`options`	Options that affect the features of the predefined task.

Return Value

An active dBHL tone audiometry task that can be presented with an ORKTaskViewController object.

Discussion

In the dBHL tone audiometry task, the participant is asked to listen to some tones with different audio frequencies, playing on different channels (left and right), that vary in dB HL values depending on whether or not the user tapped the button.

You can use a tone audiometry task to measure the hearing threshold of the user.

Declared In

ORKOrderedTask+ORKPredefinedActiveTask.h

`+ reactionTimeTaskWithIdentifier:intendedUseDescription:maximumStimulusInterval:minimumStimulusInterval:thresholdAcceleration:numberOfAttempts:timeout:successSound:timeoutSound:failureSound:options:`

Returns a predefined task that tests the participant’s reaction time.

+ (ORKOrderedTask *)reactionTimeTaskWithIdentifier:(NSString *)identifier intendedUseDescription:(nullable NSString *)intendedUseDescription maximumStimulusInterval:(NSTimeInterval)maximumStimulusInterval minimumStimulusInterval:(NSTimeInterval)minimumStimulusInterval thresholdAcceleration:(double)thresholdAcceleration numberOfAttempts:(int)numberOfAttempts timeout:(NSTimeInterval)timeout successSound:(UInt32)successSoundID timeoutSound:(UInt32)timeoutSoundID failureSound:(UInt32)failureSoundID options:(ORKPredefinedTaskOption)options

Parameters

`identifier`	The task identifier to use for this task, appropriate to the study.
`intendedUseDescription`	A localized string describing the intended use of the data collected. If the value of this parameter is `nil`, the default localized text is displayed.
`maximumStimulusInterval`	The maximum interval before the stimulus is delivered.
`minimumStimulusInterval`	The minimum interval before the stimulus is delivered.
`thresholdAcceleration`	The acceleration required to end a reaction time test.
`numberOfAttempts`	The number of successful attempts required before the task is complete. The active step result will contain this many child results if the task is completed.
`timeout`	The interval permitted after the stimulus until the test fails, if the threshold is not reached.
`successSoundID`	The sound to play after a successful attempt.
`timeoutSoundID`	The sound to play after an attempt that times out.
`failureSoundID`	The sound to play after an unsuccessful attempt.
`options`	Options that affect the features of the predefined task.

Return Value

An active device motion reaction time task that can be presented with an ORKTaskViewController object.

Discussion

In a reaction time task, the participant is asked to move the device sharply in any direction in response to a visual cue. You can use this task to accurately assess the participant’s simple reaction time.

A reaction time task finishes when the participant has completed the required number of attempts successfully. An attempt is successful when the participant exerts acceleration greater than thresholdAcceleration to the device after the stimulus has been delivered and before timeout has elapsed. An attempt is unsuccessful if acceleration greater than thresholdAcceleration is applied to the device before the stimulus or if this does not occur before timeout has elapsed. If unsuccessful, the result is not reported and the participant must try again to proceed with the task.

Data collected by the task is in the form of ORKReactionTimeResult objects. These objects contain a timestamp representing the delivery of the stimulus and an ORKFileResult, which references the motion data collected during an attempt. The researcher can use these to evaluate the response to the stimulus and calculate the reaction time.

Declared In

ORKOrderedTask+ORKPredefinedActiveTask.h

`+ towerOfHanoiTaskWithIdentifier:intendedUseDescription:numberOfDisks:options:`

Returns a predefined task that consists of a Tower of Hanoi puzzle.

+ (ORKOrderedTask *)towerOfHanoiTaskWithIdentifier:(NSString *)identifier intendedUseDescription:(nullable NSString *)intendedUseDescription numberOfDisks:(NSUInteger)numberOfDisks options:(ORKPredefinedTaskOption)options

Parameters

`identifier`	The task identifier to use for this task, appropriate to the study.
`intendedUseDescription`	A localized string describing the intended use of the data collected. If the value of this parameter is `nil`, the default localized text is displayed.
`numberOfDisks`	The number of disks in the puzzle; the default value for this property is 3.
`options`	Options that affect the features of the predefined task.

Return Value

An active device motion reaction time task that can be presented with an ORKTaskViewController object.

Discussion

In a Tower of Hanoi task, the participant is asked to solve the classic puzzle in as few moves as possible. You can use this task to assess the participant’s problem-solving skills.

A Tower of Hanoi task finishes when the participant has completed the puzzle correctly or concedes that he or she cannot solve it.

Data collected by the task is in the form of an ORKTowerOfHanoiResult object. Data collected in this task consists of how many moves were taken and whether the puzzle was successfully completed or not.

Declared In

ORKOrderedTask+ORKPredefinedActiveTask.h

`+ timedWalkTaskWithIdentifier:intendedUseDescription:distanceInMeters:timeLimit:turnAroundTimeLimit:includeAssistiveDeviceForm:options:`

Returns a predefined task that consists of a timed walk, with a distinct turn around step.

+ (ORKOrderedTask *)timedWalkTaskWithIdentifier:(NSString *)identifier intendedUseDescription:(nullable NSString *)intendedUseDescription distanceInMeters:(double)distanceInMeters timeLimit:(NSTimeInterval)timeLimit turnAroundTimeLimit:(NSTimeInterval)turnAroundTimeLimit includeAssistiveDeviceForm:(BOOL)includeAssistiveDeviceForm options:(ORKPredefinedTaskOption)options

Parameters

`identifier`	The task identifier to use for this task, appropriate to the study.
`intendedUseDescription`	A localized string describing the intended use of the data collected. If the value of this parameter is `nil`, the default localized text is displayed.
`distanceInMeters`	The timed walk distance in meters.
`timeLimit`	The time limit to complete the trials.
`turnAroundTimeLimit`	The time limit to complete the turn around step, passing zero or negative value to this parameter will bypass the turnAroundTime step.
`includeAssistiveDeviceForm`	A Boolean value that indicates whether to inlude the form step about the usage of an assistive device.
`options`	Options that affect the features of the predefined task.

Return Value

An active timed walk task that can be presented with an ORKTaskViewController object.

Discussion

In a timed walk task, the participant is asked to walk for a specific distance as quickly as possible, but safely. Then the participant is asked to turn around. The task is immediately administered again by having the patient walk back the same distance. A timed walk task can be used to measure lower extremity function.

The presentation of the timed walk task differs from both the fitness check task and the short walk task in that the distance is fixed. After a first walk, the user is asked to turn, then reverse direction.

The data collected by this task can include accelerometer, device motion, pedometer data, and location where available.

Data collected by the task is in the form of an ORKTimedWalkResult object.

Declared In

ORKOrderedTask+ORKPredefinedActiveTask.h

`+ PSATTaskWithIdentifier:intendedUseDescription:presentationMode:interStimulusInterval:stimulusDuration:seriesLength:options:`

Returns a predefined task that consists of the paced serial addition test (PSAT).

+ (ORKOrderedTask *)PSATTaskWithIdentifier:(NSString *)identifier intendedUseDescription:(nullable NSString *)intendedUseDescription presentationMode:(ORKPSATPresentationMode)presentationMode interStimulusInterval:(NSTimeInterval)interStimulusInterval stimulusDuration:(NSTimeInterval)stimulusDuration seriesLength:(NSInteger)seriesLength options:(ORKPredefinedTaskOption)options

Parameters

`identifier`	The task identifier to use for this task, appropriate to the study.
`intendedUseDescription`	A localized string describing the intended use of the data collected. If the value of this parameter is `nil`, the default localized text is displayed.
`presentationMode`	The presentation mode of the PSAT test (auditory or visual or both).
`interStimulusInterval`	The time interval between two digits presented.
`stimulusDuration`	The time duration the digit is shown on screen (only for visual PSAT, that is PVSAT and PAVSAT).
`seriesLength`	The number of digits that will be presented during the task.
`options`	Options that affect the features of the predefined task.

Return Value

An active PSAT task that can be presented with an ORKTaskViewController object.

Discussion

In a PSAT task, the participant is asked to add a new digit to the one immediately before it every 2 or 3 seconds.

A PSAT task can be used to measure the cognitive function that assesses auditory and/or visual information processing speed and flexibility, as well as calculation ability.

Data collected by the task is in the form of an ORKPSATResult object.

Declared In

ORKOrderedTask+ORKPredefinedActiveTask.h

`+ tremorTestTaskWithIdentifier:intendedUseDescription:activeStepDuration:activeTaskOptions:handOptions:options:`

Returns a predefined task that measures hand tremor.

+ (ORKNavigableOrderedTask *)tremorTestTaskWithIdentifier:(NSString *)identifier intendedUseDescription:(nullable NSString *)intendedUseDescription activeStepDuration:(NSTimeInterval)activeStepDuration activeTaskOptions:(ORKTremorActiveTaskOption)activeTaskOptions handOptions:(ORKPredefinedTaskHandOption)handOptions options:(ORKPredefinedTaskOption)options

Parameters

`identifier`	The task identifier to use for this task, appropriate to the study.
`intendedUseDescription`	A localized string describing the intended use of the data collected. If the value of this parameter is `nil`, the default localized text is displayed.
`activeStepDuration`	The duration for each active step in the task.
`activeTaskOptions`	Options that affect which active steps are presented for this task.
`handOptions`	Options for determining which hand(s) to test.
`options`	Options that affect the features of the predefined task.

Return Value

An active tremor test task that can be presented with an ORKTaskViewController object.

Discussion

In a tremor assessment task, the participant is asked to hold the device with their most affected hand in various positions while accelerometer and motion data are captured.

Declared In

ORKOrderedTask+ORKPredefinedActiveTask.h

`+ trailmakingTaskWithIdentifier:intendedUseDescription:trailmakingInstruction:trailType:options:`

Returns a predefined task that measures visual attention and task switching.

+ (ORKOrderedTask *)trailmakingTaskWithIdentifier:(NSString *)identifier intendedUseDescription:(nullable NSString *)intendedUseDescription trailmakingInstruction:(nullable NSString *)trailmakingInstruction trailType:(ORKTrailMakingTypeIdentifier)trailType options:(ORKPredefinedTaskOption)options

Parameters

`identifier`	The task identifier to use for this task, appropriate to the study.
`intendedUseDescription`	A localized string describing the intended use of the data collected. If the value of this parameter is `nil`, the default localized text is displayed.
`trailmakingInstruction`	Instructional content describing what the user needs to do when the task begins. If the value of this parameter is `nil`,
`trailType`	Type of trail to display. Either `ORKTrailMakingTypeIdentifierA` or `ORKTrailMakingTypeIdentifierB`
`options`	Options that affect the features of the predefined task.

Return Value

An active trail making test task that can be presented with an ORKTaskViewController object.

Discussion

In a trail making test, the participant is asked to connect a series of cicles labeled 1,2,3… or 1,A,2,B,3,C… and time to complete the test is recorded.

ORKTrailMakingTypeIdentifierA uses the pattern: 1-2-3-4-5-6-7. ORKTrailMakingTypeIdentifierB uses the pattern: 1-A-2-B-3-C-4-D-5-E-6-F-7

Declared In

ORKOrderedTask+ORKPredefinedActiveTask.h