[supplement] A.V. is a young herpes simplex encephalitis (HSE) survivor who suffered extensive bilateral damage to the medial temporal lobe (MTL) leading to a severe and pervasive form of anterograde amnesia. Structural Magnetic Resonance Imaging (MRI) revealed lesions that encompass the hippocampus and amygdala in both hemispheres and that extend more laterally in the right temporal lobe. At the same time, detailed neuropsychological testing showed that the disparity between A.V.’s preserved intellectual functioning (Full Scale IQ: 115) and severe memory deficit (Delayed Memory Index: 42) is one of the largest on record.
Despite this deficit, A.V. has regained a higher level of functioning and autonomy compared to previously documented amnesic cases with major bilateral MTL lesions.
As a millennial, one advantage which A.V. has over prior amnesic cases is fluency with digital technology—particularly the smartphone. The analysis of his phone and specific app usage showed a pattern that is consistent with the strategy to offload cognitive tasks that would normally be supported by the MTL.
A.V.’s behavior is important in terms of rehabilitation and may have broader implications at the societal level and for public health given the ubiquity of smartphone technology and its potential to become integrated with neural mnemonic functions.
[Keywords: brain, hippocampus, medial temporal lobe, encephalitis, amnesia]
…In conjunction with his mother’s consistent and insightful caregiving, A.V.’s use of his mobile device allows him to live independently, work, and cope in his daily life with what would otherwise be a devastating memory impairment, as discussed below.
…Phone data recording: Phone usage statistics were derived from continuous monitoring with “App Usage” (a0soft Software, Hsinchu, Taiwan) for Android over a period of 100 days (March–June 2019). Data relative to phone and app usage time were exported as CSV files and examined in Microsoft Excel. Resulting graphs were exported to Adobe Photoshop.
…He was severely impaired at recalling information, both immediately and after delays of 20–30 minutes. Following these delays, A.V. was unable to recall any of the information that had been presented to him (resulting in a raw score of 0 across multiple tests). His recognition scores were similarly in the impaired range. In fact, his performance did not improve if he was asked to pick words that had been read to him earlier from a list that also included new words. On a “yes or no” recognition test he showed a bias for yes responses (with 7 hits and 17 false positives) and a high intrusion rate (27 intrusions, which place him in the severely impaired range), highlighting his attempt to name words that were not in the list. A.V. showed no evidence that repetition helped with the learning of new declarative information.
…A.V. lives alone in a single-family home that is located a few miles from the house he grew up in. His mother lives in a separate house a block away. During the early stages of his recovery, A.V. needed constant supervision, even with very basic tasks (eg. choosing appropriate clothing for the weather, keeping up with his personal hygiene, and preparing meals); now he is largely able to perform these tasks on his own. His mother continues to provide oversight and assistance, often remotely, using text messaging.
A.V.’s mother presides over important business and safety issues, but she also occasionally resolves simple, practical problems that can nevertheless impact A.V.’s quality of life; for instance, she makes sure his refrigerator and pantry are stocked with healthy foods, something that A.V. may not do consistently. Having trained as a health professional, A.V.’s mother is exceptionally perceptive and resourceful as a caregiver. Her main objective, as she aptly describes it, is to reinforce behaviors and to teach A.V. skills that can ultimately bolster his independence, a strategy that has proven very effective so far.
Upon witnessing A.V.’s daily routine the observer gains an impression of normalcy that is atypical for an HSE survivor with such a severe memory deficit.
| Monday | Tuesday | Wednesday | Thursday | Friday | Saturday | Sunday |
|---|---|---|---|---|---|---|
| 00:00: Shower | 00:00: Shower | 00:00: Shower | 00:00: Shower | 00:00: Shower | 00:00: Shower | 1:45: Shower |
| 00:30: Bed | 00:30: Bed | 00:30: Bed | 00:30: Bed | 00:30: Bed | 00:30: Bed | 2:00: Bed |
| 6:00: Wakes up | 6:00: Wakes up | 6:00: Wakes up | 6:00: Wakes up | 6:00: Wakes up | 6:00: Wakes up | 7:00: Wakes up |
| 9:00–12:00: Sports | 9:00–12:00: Sports | 9:30–11:30: Acupuncture | 9:00–12:00: Sports | 8:00–13:00: Home upkeep | 8:00–12:00: Church & family brunch | |
| 16:00–18:00: Runs errands & visits family | 16:00–18:00: Runs errands & visits family | 16:00–18:00: Runs errands & visits family | 16:00–21:00: Work | |||
| 18:30–23:30: Work | 18:30–23:30: Work | 18:30–23:30: Work | 18:30–23:30: Work | 19:00–21:00: Nap | 18:00–1:30: Work |
Table 4 displays A.V.’s weekly schedule. It is representative of his routine habits and commitments over the past year. He works 6 days a week (averaging 30 hours) at two different jobs, one with a landscaping and cleaning crew, the other in a catering business. His day off is Friday, when he rests and catches up with household tasks and errands like doing the laundry and gardening. He regularly sleeps 6 hours at night and wakes up around the same time every morning without having to set an alarm. Throughout the day, he takes one or more rest breaks, as needed. According to his mother, these breaks are very important for his functioning and well-being. He plays a ball game 3 days a week, mixing with a regular group of people at the local community center. The ball game is his main form of physical exercise and one of the occasions in which he engages in social interactions. He eats one or two meals a day, but not at any regular time, and snacks throughout the day. A.V. visits his grandparents regularly and attends church together with his extended family on Sunday followed by brunch at the local diner, a family tradition.
A.V. drives alone to work and to visit his relatives. He has been driving for over a decade with no reported accidents or traffic citations. During this time, A.V.’s mother can cite only two instances in which he needed her help with directions: one time he wanted to be sure he knew where he could turn to get to his destination since the police rerouted all traffic due to an accident; the other is when he made a left turn instead of a right and realized he had made an error. Indeed, our own observations confirmed that he has no difficulties driving and finding his way in the local environment. We toured the neighborhood in the car and observed how he recognized many landmarks in the area, including his former schools, the location of his workplace (both past and present), and the homes where his relatives live. A.V. also drove us for 10 miles on the freeway and on secondary roads to return to his home after a day trip. On that occasion, we could confirm that he is able to navigate relatively long distances without the aid of GPS, maps, or his mother’s assistance. These observations were validated by the analysis of A.V.’s use of smartphone apps, as explained below.
A.V.’s smartphone use: At the beginning of his recovery, A.V. wrote reminders on Post-It notes. It took two years for him to resume the use of his personal computer (PC) which he used to access his music collection, photos, and the internet. He also used the PC to keep track of his tasks and to store information related to past and upcoming events. Following the introduction of smartphones, in the years after his injury, A.V. began using these portable devices and has since owned 4 different Android smartphones (HTC Hero, Galaxy S3, Galaxy S4, and Galaxy S7)…Preserved procedural memory (Figure 4) may explain A.V.’s ability to use new phones and to keep up with operating system updates and new apps.
In order to determine how A.V. uses his smartphone, we collected statistics relative to his phone and app usage over a 100-day period. The results of the analyses are displayed in Figure 5. Based on smartphone use data, A.V. activated (checked) his phone 103× per day on average (Figure 5a), spending an average of 3 hours and 3 minutes on apps and 18 minutes on phone calls each day. In total, his average daily mobile phone use was 3 hours and 21 minutes, with most days ranging between 2–4 hours of use (Figure 5a). The 5 apps most heavily used were messages, calendar, solitaire, phone, and internet browser, which together comprised 87% of his total app usage (Figure 5c). He accessed his text messages ~ 84×/day and spent more time on messages than any other application (averaging 1 hour and 11 minutes per day). Most text messages were to and from his mother, and he also received daily banking notifications, family “group” texts, and promotions from retailers.
Throughout the day, A.V. used his calendar apps to receive notifications and alerts about upcoming events and commitments. A.V. uses notifications and reminders also at work to help with the timely completion of his assignments. It appears he also uses the calendar as a running diary to send notifications to his “future self” but we have not yet probed into the nature of these personal notes. Over the 100-day period, he accessed his calendar more than any other app (averaging 84×/day).
The game Solitaire was the third most used app. He plays intermittently throughout the day (~5×/day).
Among the apps that he did not use, the most notable are e-mail and navigation maps, the latter possibly reflecting confidence in his navigation abilities, as we were able to ascertain by observing his driving behavior.
…The two apps that A.V. uses the most and that he accesses with the same frequency (~84× per day) were “calendar” and “messages”. As expected, calendar entries were frequent, and they were paired with notifications. Notifications alert him in advance of a pending task, but also motivate him to start off on his activities and to keep up with his schedule. Text messaging is equally effective in this regard. This explains the high usage of the app and the fact that most texts are between Additionally, A.V. and his mother. Indeed, texting is their main channel of communication and the way she provides her oversight, remotely, on A.V.’s commitments, activities, and whereabouts, as well as pure companionship. A.V. and his mother regularly review his schedule together in case there is a need to resolve any potential conflict or errors in the calendar entries.