Electrical and Computer Engineering Dept Human Factors in

Electrical and Computer Engineering Dept. Human Factors in VR

User (programmer, trainee, etc. ) System architecture

Human factors in VR Human Performance Efficiency Societal Implications Health and Safety (Stanney et al. , 1998)

Human factors in VR Will the user get sick in VR? Which tasks are most suitable for users in VR? Which user characteristics will influence VR performance? Will there be negative societal impact from user’s misuse of the technology? How should VR technology be improved to better meet the user’s needs? ? How much feedback from VR can the user process? Will the user perceive system limitations? What kind of designs will enhance user’s performance in VR? (Stanney et al. , 1998)

Human factors vocabulary ü HF study – series of experiments in very rigorous conditions aimed at the user (can be controlled or case study); ü Experimental protocol – establishes a structured sequence of experiments that all participants need to perform; ü Trial – a single instance of the experiment; ü Session - a sequence of repeated trials; ü Rest period – time between sessions; ü Experimental database – files that store experimental data; ü Institutional Review Board (IRB) – watchdog office regulating HF experiments ü Principal Investigator (PI) – person conducting the HF study. Needs to be certified by the IRB

H. F. vocabulary - continued Subject - a participant in a HF study (male or female, age, volunteer or paid, right handed or left handed, normal or disabled, etc); ü Experimental group – subjects on which the experiments are done; ü Control group – a number of subjects used for comparison with the experimental group; ü Controlled study – a study that uses both an experimental and control group ü Case study (also called pilot study) – smaller study with no control group. üFeasibility Study – look at technology acceptance and effect üConsent form – needs to be signed by all participants into the study; üBaseline test – measurement of subject’s abilities before trial; ü

Human factors in VR Human Performance Efficiency Societal Implications Health and Safety (Stanney et al. , 1998)

Determine focus The stages of human factors studies Develop experim. protocol Recruit subjects Conduct study Analyze data

Determine focus The stages of human factors studies Develop experim. protocol Recruit subjects Conduct study Analyze data

Human factors focus ü What is the problem? (ex. People get headaches) ü Determines the hypothesis (ex. Faster graphics is better); ü Establishes type of study (usability, sociological, etc. ); ü Objective evaluation, subjective evaluation or both? ü…

Determine focus The stages of human factors studies Develop experimental protocol Recruit subjects Conduct study Analyze data

Experimental protocol ü What tasks are done during one trial? ü How many trials are repeated per session? ü How many sessions per day, and how many days for the study? ü How many subjects in experimental and control group? ü What pre and post-trial measurements are done? ü What variables are stored in the database? ü What questions on the subjective evaluation form?

Determine focus The stages of human factors studies Develop experim. protocol Recruit subjects Conduct study Analyze data

Subject recruitment ü Sufficient number of subjects need to be enlisted in the study to have statistical significance; ü Place advertisements, send targeted emails, web posting, go to support/focus groups, friends, etc. ; ü Subjects are screened for unsuitability to study; ü Subjects sign consent form; ü Subjects are assigned a code to protect their identity; ü Subjects sign release for use of data in research, üSubjects may get “exposure” to technology;

Determine focus The stages of human factors studies Develop experim. protocol Recruit subjects Conduct study Analyze data

Determine focus The stages of human factors studies Develop experim. protocol Recruit subjects Conduct study Analyze data

Data Collection ü VR can sample much larger quantity of data and at higher temporal density than classical paper-and-pencil methods; ü Data recorded online can be played back during task debriefing and researchers do not have to be co-located with the subjects (remote measurements); ü Measurements need to be sensitive (to distinguish between novice and expert users), reliable (repeatable and consistent) and valid (truthful); ü Latencies and sensor noise adversely affect these requirements.

Data Analysis ü Experiments store different variables, depending on the type of test: task completion time – time needed to finish the task (can use system time, sequence of actions, or stopwatch); § task error rate – number or percentage of errors done during a trial; § task learning – a decrease in error rate, or completion time over a series of trials; § Analysis of Variation (ANOVA) – statistical package used to analyze data and determine if statistical difference exists between trials or conditions. §

Data analysis - continued Error rates Standard deviation Average Task learning 1 2 3 Trial number Learning results in less errors and more uniform performance among subjects

Data analysis - continued Group C (very difficult task) Error rates Group A Group B (very easy task) 1 2 3 Trial number Effect of prior knowledge on task learning

Data analysis - continued Monoscopic Group, small fps, high fps variability Error rates or completion time Stereoscopic Group High fps, small variability in fps N H H-A Feedback modality

Data analysis - continued üTask learning time and error rates are applicable to VR in general; üPerformance measures which are modality specific – for example force feedback - Average contact force – the forcefulness of the interaction with a virtual object N ∑i=1 fi Average force =____ N where N is the number of data samples and fi is the magnitude of the i-th force

Data analysis - continued üAnother modality-specific performance measure is the cumulative contact force. Higher cumulative forces/torques indicate higher subject’s muscle exertion ü This can lead to muscle fatigue of haptic interface premature wear. N Cumulative force = ∑i=1 fi Xt Where t is the sampling interval ü There also task-specific performance measures, such as those associated with cognitive tasks (heart rate, muscle tone, skin conduction, breathing rate, etc. )

Usability Engineering ü A subclass of human factors research to determine the ease (or difficulty) of use of a given product; ü It differs from general-purpose VR human factors studies which are more theoretical in nature; ü Usability studies are product-oriented and part of the product development cycle. ü There are no clear standards, because this is an area of active research.

Usability Engineering üThe methodology consists of four stages: User task analysis Expert guidelinesbased evaluation Formative Usability evaluation Summative evaluation

“Sea Dragon” military command control application

Usability Engineering üThe first stage – define the task and list user’s actions and system resources needed to do it; User task analysis ü Identifies the interrelationships (dependencies and order sequences) and user information flow during the task; ü Poor task analysis is a frequent cause of bad product design. ü For Dragon, the task is 3 -D navigation and object (symbol) selection and manipulation. ü it differs from classical 2 -D maps and symbols. Expert guidelinesbased evaluation Formative Usability evaluation Summative evaluation

Usability Engineering üThe second stage (sometimes called heuristic evaluation) aims at identifying potential usability User task analysis problems early in the design cycle. ü A pencil-and-paper comparison of user’s actions done by experts, first alone, and then as a group (to determine consensus); ü For Dragon, ease of navigation was identified as a critical issue; experts identified problems with the system responsiveness, when using a flight stick (wand with buttons) and performing “exocentric” navigation (the user was outside of the environment, looking in). Expert guidelinesbased evaluation Formative Usability evaluation Summative evaluation

üThe third stage is an iterative process where representative users are asked to perform the task; ü During task performance variour variables are measured, such as task completion time and error rates. These are used to do product redesign and the process is repeated; ü Dragon formative evaluation had two stages. During the first stage the best interface was selected between three candidates (Pinch. Glove, voice recognition and wand). Voice recognition was ineffective, and Pinch. Glove produced time delays when transferring to another user. Thus wand was selected. Usability Engineering User task analysis Expert guidelinesbased evaluation Formative Usability evaluation Summative evaluation

üThe second stage of Dragon formative evaluation used a large number of subjects that had to navigate, while errors were recorded. ü A large effort was made in mapping the wand button to functions. Pan and zoom were mapped to the wand trigger, pitch and heading to the left button, while exocentric rotate and zoom were mapped to the right button Usability Engineering User task analysis Expert guidelinesbased evaluation Formative Usability evaluation Summative evaluation

Usability Engineering üThe last stage is Summative evaluation which is done at the end of product development cycle. It is done to statistically compare the new product User task analysis with other (competing) products to determine which is better. The selection among several Expert guidelinescandidates is done based on field trials and expert based reviews. evaluation ü The summative evaluation of Dragon involved the study of four parameters: navigation metaphor (egocentric or exocentric), gesture mapping (rate or position control of camera), display device (workbench, desktop, wall or CAVE) and graphics mode (stereo or mono) Formative Usability evaluation Summative evaluation

Usability Engineering ü The summative evaluation of Dragon involved thirty two subjects divided in groups of four. Each group was assigned a different combination of conditions.

Usability Engineering üResults showed that users: o performed fastest on a desktop monitor; o were slowest on the workbench. o Egocentric navigation was fastest in monoscopic graphics o Exocentric navigation was fastest in stereo graphics. o Rate control was fastest in monoscopic graphics; o Position was fastest for stereo graphics.

Testbed Evaluation of Universal VR Tasks ü Testbeds are a way to deal with evaluation complexities. ü They are composed of a small number of “universal” tasks such as travel in a virtual environment, object selection and object manipulation; ü Provide a structured way to model subject performance, although the evaluation is more expensive to do. ü Testbeds make possible to predict subject’s performance in applications that include the tasks, sub-tasks and interaction techniques they use.

Testbed Evaluation of Universal VR Tasks - continued ü Testbed evaluation of navigation tasks: obstacles (trees and fences) and targets (flags) can be randomly placed. ü There were 38 subjects divided in 7 groups, each using a different Navigation technique (steering based, manipulation-based and target specification techniques)

Testbed Evaluation of Universal VR Tasks - continued ü Steering-based: Pointing, gaze tracking or torso tracking; ü Manipulation-based: HOMER or Go-Go; In go-go the subject stretches his hand into the virtual world, grasps an object and then pulls the virtual camera forward; ü Target-specification: ray casting or dragging. ü Fastest – gaze-directed (but produced eye strain and nausea)

Testbed Evaluation of Universal VR Tasks - continued ü Testbeds used for object selection and placement tasks; ü Subjects had to select a highlighted cube and place it in a target area (between the two gray cubes);

Testbed Evaluation of Universal VR Tasks - continued ü There were 48 subjects divided among 9 groups. Object selection was done either by ray casting or occlusion. Scene was seen on HMD; ü For each subject the distance to the object, the DOF used for box Manipulation (2 or 6) or ratio of object/target size (1. 5 x, 3. 75 x) varied. ü Distant objects were harder to select, Go-Go was slowest mode.

Influence of System Responsiveness on User Performance ü System responsiveness inverse proportional to the time between user input and the simulation response to that input. üHF studies done at Rutgers in early 90 s to determine influence of refresh rate (fps) and graphics mode (mono/stereo) on tracking task performance in VR; üSubjects were 48 male and 48 female (volunteer undergrad students), right handed. Task was the capture of a bouncing ball in the smallest amount of time; ü Subjects were divided in sub-groups, each having a different refresh rate, and graphics mode; ü Each subject performed 12 trials separated by 15 seconds rest periods; üBall appeared with random velocity direction and maintained a speed of 25 cm/sec

Influence of System Responsiveness on User Performance

Influence of System Responsiveness on User Performance ü Ball capturing time was influence sharply by the graphics refresh rate, especially when the rate fell below 14 fps; ü The standard deviation grew with the decrease in fps, indicating less uniformity among the subjects in the experimental groups; ü Stereo made a big difference for low refresh rates, where task completion time was approximately 50% of the time taken to complete the task under monoscopic graphics; ü the subjects had different strategies for grasping the ball üAt low refresh rates, where the ball motion appeared saccadic, they grasped in a corner, keeping their arm stationary, üAt high refresh rates they moved theirs hand in a ballistic way to capture it.

Mean completion time (sec) Influence of System Responsiveness on User Performance Mono graphics Stereo graphics Frames per second (fps) Effect of frame rate and graphics mode on task completion time (Richard et al. , 1995)

Influence of System Responsiveness on User Learning ü The frame refresh rate had a significan influence on the way subjects learned; ü The group with highest task learning was that corresponding to monoscopic graphics displayed at 1 fps. completion time (sec) Mono graphics Trial number

Influence of System Responsiveness on User Learning üThe least learning was for the groups with high refresh rates (14 fps and 28 fps). Their curves were almost flat; ü Stereo had a beneficial effect on learning (subjects were more familiar to the task – it was presented more realistically to them). completion time (sec) Stereo graphics Trial number

Influence of System Responsiveness on Object Placement tasks üWatson performed a test to determine the influence of system responsiveness and its variability (expresses as Standard Deviation of System Responsiveness) on object placement tasks. ü The task was to capture an object and place it on a pedestal, while receiving monoscopic graphics feedback; ü System responsiveness was altered by changing the frame refresh rates to 17 fps, 25 fps and 33 fps. For each frame rate, the SDSR was changed from 5. 6%, 22. 2% and 44. 4%;

Influence of System Responsiveness on Object Placement tasks üResults showed that subject performance (expressed as placement time and accuracy) was effected by both SR and SDSR. ü The variability in system responsiveness had the largest influence on placement tasks done at low refresh rates. The worst was placement done at 17 fps, with 44. 4% SDSR. ü When done at 33 fps and 5. 6% SDSR accuracy improved 90%.

Influence of System Responsiveness on Object Placement tasks

Influence of Feedback Multi-modality ü HF studies done at University of Birmingham in late 90 s to determine influence of force feedback mode on task completion time in VR; ü Task was the manipulation of disks to construct the “Tower of Hanoi”. ü Four conditions – non-immersive VR with 2 -D mouse, immersive (HMD) with 3 -D mouse, immersive with instrumented objects, and real objects; ü Use of “instrumented objects” (disks with a tracker attached) to provide force feedback – augmented VR ü Subjects were four male with six-months experience in VR each; ü Each subject performed 10 trials for each condition, conditions were randomized.

Influence of Feedback Multi-modality Problem – Stack three rings on another pole; Larger ring never on top of smaller one 1 2 3 5 6 Tower of Hanoi task 4 7

Influence of Feedback Multi-modality experimental setup (IO condition) 3 -D manipulation task – Tower of Hanoi Virtual scene during experiments (Boud et al. , 2000)

Task completion time (sec) Influence of Feedback Multi-modality Tower of Hanoi performance experimental condition (Boud et al. , 2000)

Influence of sensorial redundancy and substitution Definition Sensorial substitution (or transposition) occurs whenever information that is usually in one sensorial domain is presented to the brain through another sensory system. Sensorial redundancy involves the use of several (at least two) sensorial domains to present the same information to the subject.

Influence of sensorial redundancy and substitution ü HF studies done at Rutgers in mid 90 s to determine influence of force feedback mode on task performance in VR; ü Task was the manipulation a deformable virtual ball on a prescribed path, in shortest time; ü Ball needed to be deformed 10% of radius or less; ü Subjects were male and female (volunteer undergrad students), right handed, and none had seen the system before; ü Subjects were divided in sub-groups, each having a different force feedback modality and graphics mode; ü Frame rate was maintained at 28 fps; ü Each subject performed 12 trials separated by 15 seconds rest periods;

Influence of sensorial redundancy and substitution 3 -D capturing and manipulation task setup

Influence of sensorial redundancy and substitution Sensorial substitution

Mean object deformation (%) Influence of sensorial redundancy and substitution RMII 3 -D manipulation task Force Feedback Modality Effect of interface dynamic range on task performance (Fabiani et al. , 1996)

Sensorial Illusion ü This happens during cross-modal “enhancement” – when weak haptic feedback is supplemented by another modality. Example – Biocca’s study found that 30% of subjects reported feeling the weight and inertia of virtual objects when interacting with Pinch. Gloves

Sensorial Illusion ü Another form of sensorial illusion is provision of haptic texture feedback through vision ü By manipulating the gain in mouse arrow movement in response to user real movement it is possible to simulate bumps and valleys in the object surface Supplemental video Download and experience these textures from http: //www. irisa. fr/tactiles/index-eng. html

Sensorial Conflict ü Another form of sensorial illusion in sensorial conflict in which information from one sensorial channel contradicts that received by another sensorial channel. ü An extreme case of sensorial conflict is simulation sickness which will be discussed later. ü French researchers studied the “boundary of illusion” between conflicting visual and haptic feedback. VC 7. 1

Human factors in VR Human Performance Efficiency Societal Implications Health and Safety (Stanney et al. , 1998)

Effects of VR Simulations on users The effects VR simulations have on users can be classified as direct and indirect; Definitions Direct effects involve energy transfer at the tissue level and are potentially hazardous; Indirect effects are neurological, psychological, sociological, or cybersickness and affect the user at a higher functional level.

Direct Effects of VR Simulations on Users ü Affect mainly the user’s visual system, but also the auditory, skin and musculoskeletal systems; ü Effects on the skin and muscles are due to haptic feedback at too high a level. üThe intensity of Wii game playing can lead to injury. Statistics posted on http: //www. wiihaveaproblem. com/damage. php

Direct Effects of VR Simulations on Users üEffects on the visual system occur when the user is subjected to high-intensity lights directed at his eyes (like Lasers used in retinal displays (if they malfunction), or IR LEDs as part of eye tracking systems; ü An “absence” state can be induced in a user subjected to pulsing lights at low frequency (1 -10 Hz); ü Bright lights coupled with loud pulsing sounds can induce migraines (20% of women and 10% of men are prone to migraines. ü Direct effects on the auditory system are due to simulation noise that has too high a level (115 d. B after more than 15 minutes);

Cyber sickness ü User safety concerns relate primarily to cyber sickness, but also to body harm when haptic feedback is provided; ü Cyber sickness is a form of motion sickness present when users interact with virtual environments; ü Cyber sickness has three forms: § Nausea and (in severe cases) vomiting; § Eye strain (Oculomotor disturbances); § Disorientation, postural instability (ataxia) and vertigo. ü Flight simulators have an incidence of up to 60% of users experiencing simulation sickness (military pilots – elite group); ü Studies suggest regular VR users are affected more (up to 95%) (Stanney and Hash, 1998)

Cyber sickness Model ü Since many users are affected, it is important to study cyber sickness, in order to reduce its effects, and allow wide-spread use of VR; ü Few studies exist. Based on these the following model was developed: Prior Experience Human Body Neural Conflict Adaptation Virtual Environment Simulation sickness Aftereffects

The Cyber sickness model Prior Experience Human Body Neural Conflict Adaptation Virtual Environment Simulation sickness After-effects

System characteristics influencing cyber sickness ü When VR technology has problems, it can induce simulation sickness. Example: - Tracker errors that induce a miss-match between user motion and avatar motion in VR; - System lag that produces large time delays between user motion and simulation (graphics) response. Lag is in turn influenced by tracking sampling speed, computer power, communication speed, and software optimization. - HMD image resolution and field of view. Poor resolution and small FOV are not acceptable. Large FOVs can also be problematic.

Influence of user’s characteristics on cyber sickness ü The user characteristics can play an important role in cyber sickness: - Age that induce a miss-match between user motion and avatar motion in VR; - Health status. Sick users, including those that take medication or drugs are more prone to cyber sickness. - Pregnancy. Female users who are pregnant are more prone to simulation sickness. - Susceptibility to motion sickness. Some people are more prone to motion sickness than others. Pilots are screened for such.

The Cyber sickness model Prior Experience Neural Conflict Adaptation Virtual Environment Human Body Degree of Interactivity Simulation sickness After-effects

Influence of user’s degree of interactivity on cyber sickness ü HF studies done at University of Central Florida (Stanney and Hash, 1998) to determine influence of user degree of control on cyber sickness in VR; ü Task was 3 -D navigation in a maze (shown below): 3 -D navigation task (Stanney and Hash, 1988)

Influence of user’s degree of interactivity on cyber sickness ü There were three control conditions: § Passive control – users were “taken on a ride” on a preprogrammed path, and had no input to the simulation; § Active control – users navigated using a joystick with 6 DOF; § Combined active-passive control – users navigated using the same joystick, but with some degrees of freedom disabled, based on taskspecific motions (doors, windows, elevators); ü There were eight subjects in each experimental group (24 total, both male and female); They each performed the task for 30 minutes; ü The virtual environment was displayed on a PC in stereo, so subjects wore stereo glasses. ü Results showed that active-passive control reduced significantly cyber sickness effects. Passive control did worse. 3 -D navigation task (Stanney and Hash, 1988)

SSQ Score Influence of user’s degree of interactivity on cyber sickness ü Active-passive control is better than active control, because unnecessary motions are eliminated, thus reducing the amount of neural conflicts. Both reduce adaptation time. ü Simulation sickness was self-reported by subjects using a Simulation Sickness Questionnaire (SSQ) Passive Control Active-Passive Control Nausea Oculomotor Disorientation Total severity distortion 3 -D navigation statistics (Stanney and Hash, 1988)

The Cyber sickness model Prior Experience Human Body Neural Conflict Adaptation Virtual Environment Simulation sickness After-effects

Neural Conflict ü Occurs when simulation and body sensorial feedbacks conflict; ü The conflict (sensorial rearrangements) can be of three types: § Type I: two simultaneous conflicting signals (A and B) – example Information from a moving platform does not coincide with the motion of waves seen on an HMD. § Type II: Signal A is present and B is not – example looking at a roller coaster simulation, without a motion platform; § Type III: Signal B is present and signal A is not – flight simulation in fog (instrumented flight). Motion platform moves, but visual feedback is unchanged. ü Since more information from the simulation results in more conflict, it is logical that neural conflict induced cyber sickness grows with the duration of immersion in the VE.

Influence of exposure duration on cyber sickness ü HF studies done at University of Central Florida (Kennedy et al. , 2000) to determine influence of simulation duration on cyber sickness; ü Task was flying a helicopter, and subjects were military pilots; ü The data was divided according to duration in: § Simulation session of 1 hour or less; § 1 to 2 hours; § 2 to 3 hours; § Simulation session of over three hours ü It showed that there is a linear relationship between duration of simulation and the degree of simulation sickness; Thus the duration of initial exposure should be limited, to minimize discomfort;

Average Total Sickness Score Influence of simulation duration on cyber sickness Flight Session Duration (in hours) (Kennedy et al. , 2000)

The Cyber sickness model Prior Experience Human Body Neural Conflict Adaptation Virtual Environment Simulation sickness After-effects

Influence of repeated exposure on cyber sickness HF studies done at University of Central Florida (Kennedy et al. , 2000) to determine influence of user adaptation on cyber sickness; ü Since prior neural images play such an important role in cyber sickness, can repeated exposure to VR desensitize the user? ü Study looked at military helicopter simulators, thus subjects were pilots, and task was prone to induce sickness (violent maneuvers). ü

Influence of repeated exposure on cyber sickness üThe study used a “Total Sickness Score” with a 35% as zero-point. Thus for military pilots 35% incidence of simulator sickness is considered acceptable. For the general public it is not. ü Results showed a significant reduction in TSS after a few flights showing that the subject had adapted to the neural mismatch. While mismatches exist, there are considered as matches due to prior experience.

Influence of repeated exposure - results Average Total Sickness Score ü The study did not indicate how long the subsequent exposures should be, nor over what time interval they should take place. It is believed that no more than one week should separate simulation sessions. Flight Number Cyber sickness scores vs. number of successive flights (Kennedy et al. , 2000)

Adaptation Definition “Adaptation to sensory rearrangement is a semi-permanent change of perception and/or perceptual-motor coordination that serves to reduce or eliminate a registered discrepancy between, or within, sensory modalities, or the errors in behavior induced by this discrepancy. ” Hand-eye coordination adaptation [Groen and Werkhoven 1998]. a) before VR exposure b) initial mapping through artificial offset c) adapted grasping d) aftereffects

The Cyber sickness model Prior Experience Human Body Neural Conflict Adaptation Virtual Environment Simulation sickness Aftereffects

Aftereffects Induced through adaptation to neural conflicts. ü Occur after the simulation session ended and can last for hours or days; ü While adaptation is good, aftereffects may be bad. Forms of aftereffects are: § Flashbacks; § Sensation of “self motion”; ü

Aftereffects üHeadache and head spinning; § Diminished (remapped) hand-eye coordination; § Vestibular disturbances; ü These aftereffects lead Navy and Marines to institute grounding policies after simulator flights. Other bans may be necessary (example driving, biking, roof repair, operating machinery, etc. ).

Guidelines for Proper VR Usage Meant to minimize the onset and severity of cybersickness. They are largely qualitative

Guidelines for Proper VR Usage

Human factors in VR Human Performance Efficiency Societal Implications Health and Safety (Stanney et al. , 1998)

Social implications of VR ü Violence of VR games are a concern, as additive response could result. Violence may also induce desensitization to real-world violence. This may be another negative “after-effect” of VR. ü Another social impact may be increased individual isolation, through reduced societal direct interaction and involvement. Avatar-mediated interaction, while allowing sharing of virtual worlds may not be a substitute to direct human-human interaction.

Social implications of VR Second Life Online Society People become members, then can build communities or islands, buy at virtual stores and play games. “An online 3 D virtual world imagined and created by its Residents http: //secondlife. com

Create content Second Life Online Society Socialize Events/Game s

Social implications of VR üSynthetic and distance learning using VR may not adequately replace direct student-professor interaction. Reduction in education quality may result; ü Reduction in health-care quality may also be present – especially for mental health and at-home rehabilitation. üHowever for seniors VR reduces the sense of isolation and ü Can be used in “brain” training.

Mental rehabilitation VR systems üOne form of game-based mental training is the Nintendo DS and Nintendo DS Lite üIt allows seniors to have fun while playing mind-challenging games, using a stylus and voice input üBrain Age 2 has 100 activities designed to help work your brain and increase blood flow to the prefrontal cortex.

Mental rehabilitation VR systems ü When starting a new game, you will take a series of tests that show old your brain is (“Brain Age”). üWith daily training over weeks and months, you can improve your mental acuity and lower your Brain Age. üCan compete against others

Online Cognitive Rehabilitation üThe Lumosity Co. (lumosity. com) allows subscription ($10/month) to video games that train the attention, memory, cognitive control and processing speed with against-the-clock games. üAfter 30 sessions subjects that played the games also improved in independent tests of memory.

The dangers of video games (general) üExcessive game play can be fatal. In Korea, where 30% of the population subscribes to online multiplayer games, one man died in 2005 after playing 50 hours (almost non-stop) Star. Craft. 3 Chinese died in 2007 after playing more than 50 hours, and 2 died in 2005. Ever. Quest is a 3 D online game played by more than 400, 000 people; Games can lead to isolation, and suicide. Hudson Wooley, an epileptic who was playing 12 -hours per day, eventually committed suicide.