App details
ITACA Dual N-Back
The computerised version of the classic neurocognitive test for the assessment of working memory.
The n-back task is a continuous performance task that is commonly used as an assessment in psychology and cognitive neuroscience to measure central executive function from working memory. The n-back was introduced by Wayne Kirchner in 1958. The subject is presented with a sequence of stimuli, and the task consists of indicating when the current stimulus matches the one from n steps earlier in the sequence. The load factor n can be adjusted to make the task more or less difficult. The dual-task n-back task is a variation that was proposed by Susanne Jaeggi et al. in 2003. In the dual-task paradigm, two independent sequences are presented simultaneously, typically using different modalities of stimuli, such as one auditory and one visual. This application allows simultaneous recording of the user's EEG signal, as well as other biosignals that can be transmitted via LSL.
Details
Dual N-back: The popular test for working memory assessment
Tested on MEDUSA© Platform v2024.0
Here we present the computerized version of Dual N-back test that is broadly applied in neuroconitive research and cognitive evaluation. This app is provided as a evaluation complement of ITACA NF framework.
What does this test consist of?
In N-back test, users are presented with a sequence of stimulus and they must indicate when a stimulus matches the stimulus presented N-times before. The dual-task N-back task is a variation that was proposed by Susanne Jaeggi et al. in 2003. In the dual-task paradigm, two independent sequences are presented simultaneously, typically using different modalities of stimuli, such as one auditory and one visual.
What does this implementation include?
The version implemented in MEDUSA© is provided with the following functionalities:
- It is possible to use this app with conjuntion of any type of biosignal device that can be connected to MEDUSA© Platform via LSL. This makes possible to analyze interesting physiological information related to the cognitive processes involved during task performance.
- Relevant session information such as identifier of the user who performed the task, number of run or session can be included in recording file. This is intended to help in subsequent analyses.
- There are included three task modes: (i) visual (the stimulus are presented as squares in a 3 x 3 grid); (ii) auditory (the stimulus are presented as letters); and (iii) dual (both types of stimulus are presented simultaneously). Noteworthy, it is included both Spanish and English as languages to perform the auditory and dual modes.
- The N load factor, the number of stimulus trials, as well as the percentage of target stimulus can be easily configured in app configuration panel.
Dual N-Back App Tutorial
Welcome to the Dual N-back app tutorial! Here we will explain you step by step how to configure the different options presented by this app.
Getting started: Configuration panel
This application has been developed as a complement to the ITACA NF framework. Therefore, its design is intended to be as flexible as possible, providing different options to enable diverse assessment protocols.
The different configuration options are divided into the following sections: (i) Run settings; and (ii) App settings.
Below, we will go through each of the following sections specifying each of the parameters to be configured. In addition, the panel has 4 main buttons:
- Load: Allows to load a JSON file with the app configuration. This is intended to facilitate the reproducibility of the experiments.
- Reset: Sets the default configuration.
- Save: Allows to save the current configuration as a JSON file.
- Done: Closes the configuration panel and confirms the selected options.
Run settings
This section contains several fields aimed at defining experiment information that may be useful in posterior analyses. For instance, it can help in identifying and managing the different recordings throughout a study. Montage standard field is intented to save the standard used (i.e., 10-20, 10-10 or 10-05) in case you want to record the EEG signal during the experiment. Otherwise, this field should be ignored.
App settings
This section includes the options related to Dual N-back task. Number of trials allows to define how many stimulus will be presented during the task performance. Target trials establish the percentage with respect to total trials that will be target, that is, those stimulus which user will have to respond.
N-back mode allows to adjust the load factor N. A N value of 0 changes the task paradigm: User will have to respond only when an specific stimulus appears. For Visuo-spatial mode, this stimulus corresponds to the central square. For Auditory mode, this stimulus corresponds to R letter. For Dual mode, both mentioned stimulus.
Game mode establish the modality of the task: If Visuo-spatial mode, stimulus will be green squares appearing in different positions of a 3 x 3 grid, whereas Auditory mode, stimulus will be different letters pronounced in English or Spanish (depending on the selected option in Language field). The Dual mode will present both types of stimulus simultaneously, and the user will have to respond separately to each type of stimulus.
Run the application
Once you have the configuration ready and you have overwritten the chosen options by pressing the Done button on the configuration panel, you must press the Power button of the MEDUSA© Platform with the Dual N-back app selected.
The first think you have to take into account is that this app enables the simultaneous recording of any kind of biosignal which device can be connected to MEDUSA© via LSL protocol. You will be reminded of this with a dialog box in case no LSL stream has been connected to the MEDUSA© Platform. The dialog is displayed bellow:
The Unity application will then be launched. Wait until the text Waiting appears in the application, then press the MEDUSA© Platform Play button. If you have chosen the option N = 0, you will be prompted with instructions for the buttons on your keyboard to press when the target stimuli are displayed. The buttons to be pressed are as follows:
- Letter J for visual stimuli (Visuo-spatial and Dual modes).
- Letter F for visual stimuli (Auditory and Dual modes).
| In order for the application to detect the user's responses, the focus must be on the application. This is done by clicking with the mouse on the application once it is started with Play. |
When the test is completed, a summary will be displayed on the screen, including the number of target stimulus correctly answered, as well as the incorrect answers. Then, press Stop button in MEDUSA© Platform to close the app window. A dialog box will appear to save the experiment information. Among the information stored is the time instant at which each stimulus was presented, whether it was a target or not, the user's response time and whether the response was successful or not. In addition, if a biosignal is recorded, it is included in this file.
If you have any questions or suggestions for improvement, please do not hesitate to contact me.