Friday, July 01, 2016

Newly Discovered EEG Rhythm Related to Texting, or Cell Phone Artifact?

Texting Zombie (by Ian Aberle)


Contemporary consumers of science infotainment “need” to understand that the brain responds to modern technology in an unprecedented and potentially sinister way. Or at least, that's what you'd think, based on the number of books and essays on how The Internet and Digital Technologies are destroying our brains. The latest entrée into this lucrative genre of mild techno-paranoid is from Elsevier, with their press release about a poorly controlled observational study in a relatively obscure journal:

Sending text messages on a smartphone can change the rhythm of brain waves, according to a new study published in Epilepsy & Behavior.
. . .

Dr. Tatum, professor of neurology and director of the epilepsy monitoring unit and epilepsy center at Mayo Clinic in Jacksonville, Florida found a unique 'texting rhythm' in approximately 1 in 5 patients who were using their smartphone to text message while having their brain waves monitored.

The publishing giant spawned a flood of news stories which claim that texting triggers a Unique, Never-Before-Seen Brain Rhythm that Actually Changes the Way Your Brain Thinks.

But here's what we don't know about the 'texting rhythm'. We don't know:
  • That the signal represents brain activity, rather than a biological artifact (e.g., eye movements) or an electromagnetically-induced artifact produced by the smartphone
  • That the 'texting rhythm' has never been seen before, given the lack of systematic studies
  • That it occurs in people without epilepsy
  • That it has any direct relation to how we think

In a series of two [largely overlapping] studies, Tatum and colleagues (2016a, 2016b) recorded noninvasive EEG (brainwave) activity from inpatients undergoing continuous video monitoring for potential seizure activity. In the more recent paper (2016b), records from 129 texting patients were reviewed for the presence of a reproducible texting rhythm (TR), defined as “a distinct, paroxysmal, time-synched, rhythmic, generalized, frontocentral, 5–6 Hz, monomorphic, theta rhythm repeatedly induced by text messaging” (based on their 2016a study with 100 patients).



Fig. 1 (adapted from Tatum et al., 2016b). (B) unilateral texting with the right hand (picture insert) during video-EEG monitoring. Note the presence of the TR as a 5–6-Hz frontocentral monomorphic rhythm (blue boxes) at the start and termination of texting (solid blue arrows).


It's hard to see what's going on here, so I've zoomed in on the lower box, which shows activity from two bipolar derivations. The Fp1-F3 trace shows eye movements and the F3-C3 trace shows the TR. It appears to be more rhythmic in these left hemisphere electrodes contralateral to the texting hand, but the TR can also be seen in the F4-C4 derivation in Fig 1B.


Although I'm just making qualitative guesses here, I don't think the EEG was quantified with spectral power or time-frequency analyses. In other words, epochs of EEG during texting vs. other activities (audio telephone use, thumb/finger movements, cognitive testing/calculation, scanning eye movements, and speech/language tasks) were eyeballed for the presence or absence of TR. We learn that the TR lasted from 2 sec to continuous runs of  >10 sec. We don't know the number or duration of epochs during the various control activities, but the authors declared a startling significance level:
The TR was highly specific to this text messaging (p < 0.0001). A similar waveform during baseline activation with motor, speech/language, and cognitive tasks performed independently was absent in all patients and was not observed during auditory–verbal smartphone communication (p < 0.0001).

The TR didn't habituate with repeated texting, wasn't specific to iPhone vs. Android, and “was observed in a patient using an iPad, though we did not observe it during the use of a laptop.”

But most texting patients undergoing video EEG monitoring did not show a TR. The percentage of patients with a TR was 24.5% (24 out of 98) and 22.6% (7 out of 31) in a separate Chicago cohort (Tatum et al, 2016a), and only 20.9% (27 of 129) in the 2016b paper. Having a TR wasn't related to age, sex, type of seizure (focal, generalized, epileptic, non-epileptic), or presence/absence of brain lesion on MRI. And we have absolutely no explanation for why that might be, which inspired this hilarious, overly honest headline:

Neuroscientists just found that texting alters your brainwaves, but they can’t explain why

Does using a smartphone fundamentally alter the way that your brain works? ...a group of researchers at the Mayo Clinic recently discovered that text messaging elicits a change in the regular rhythm of brain waves, completely different than the waveforms created by any other activity.

“The big deal with discovering this ‘texting rhythm’ is that the number of new brain waves that are identified on EEG are extremely rare at this point in time,” Dr. William Tatum, the lead author of the study, tells Digital Trends.

Dr. Tatum says that the new brain waves were discovered by accident when analyzing the day-to-day cortical rhythms of people suffering from epilepsy. This discovery triggered an investigation into the neurological effects of smartphone use, which ultimately grew to include nearly 130 participants over a period of 16 months. Only around one in five participants demonstrated the “texting rhythm,” although it didn’t appear to conform to any single gender, ethnicity or age group. Nor is it known exactly what aspect of texting prompts the effect: since text messaging includes a variety of different skills, such as finger dexterity, formulating succinct communications and more.

What we do know is that cell phones and other devices can produce artifacts in EEG recordings (Sethi et al., 2007; Rasquinha et al., 2012; Myers et al., 2016), and this was not discussed in the paper.


Dr. Ranjith Polusani, Artifacts in EEG


EEG Artifact Recognition: Electrical and Environmental Artifacts [cellphone]


But I don't mean to be so pedantic. William O. Tatum, D.O. is a neurologist and member of the American Board of Clinical Neurophysiology who has published Handbook of EEG Interpretation, Second Edition, How not to read an EEG (Neurology, 2013), Artifact-related epilepsy (Neurology, 2013), and more (see References). In fact, here's another image of a telephone artifact from Tatum et al. (2011). Dr. Tatum presumably knows a non-physiological artifact when he sees one.



So does that mean I believe the TR is real? I'll withhold judgment until the results from carefully controlled, quantitatively analyzed, statistically rigorous experiments in participants with and without epilepsy are in. Meanwhile, speculating on the origin, meaning, or relevance of the 'texting rhythm' is premature...

“The question we’re trying to answer right now is whether this is a destructive process or an active process,” Dr. Tatum says. “We think it’s probably an active process through an entrainment of normal cortical rhythms. What’s strange is that it appears to be a destructive frequency that’s more typically identified in people that have a slowing of their brain waves.”


References

Myers KA (2016). Cell Phone Saccades: EEG Artifact for the 21st Century. Pediatric Neurology. Available online 25 June 2016.

Rasquinha RJ, Moszczynski AJ, Murray BJ. (2012). A modern artifact in the sleep laboratory. J Clin Sleep Med. 8(2):225-6.

Sethi NK, Sethi PK, Torgovnick J, Arsura E. (2007). Telephone artifact in EEG recordings. The Internet Journal of Neuromonitoring. 5(1).

Tatum WO, Dworetzky BA, Schomer DL. (2011). Artifact and recording concepts in EEG. J Clin Neurophysiol. 28(3):252-63.

Tatum WO. (2013). How not to read an EEG: introductory statements. Neurology 80(1 Suppl 1):S1-3.

Tatum WO. (2013). Artifact-related epilepsy. Neurology 80(1 Suppl 1):S12-25.

Tatum WO, DiCiaccio B, Kipta JA, Yelvington KH, Stein MA. (2016a). The Texting Rhythm: A Novel EEG Waveform Using Smartphones. J Clin Neurophysiol. Jan 7. [Epub ahead of print]

Tatum WO, DiCiaccio B, Yelvington KH. (2016b). Cortical processing during smartphone text messaging. Epilepsy Behav. 59:117-21.

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2 Comments:

At July 01, 2016 9:29 PM, Blogger practiCal fMRI said...

Definitely bizarre, slash interesting. Phones and iPads communicate via cellphone signals whereas laptops generally don't/can't. All three categories of device can use wifi, however. (I assume the laptops were connected to wifi. If not, that's another line of investigation.) So one control experiment to run would be to set the phones and iPads to Airplane mode and see whether the TR persists. I can still send texts via wifi to another iPhone, for example. This is iMessage over wifi instead of SMS via the cell signal. (An even more rigorous comparison would be to do the whole thing in a Faraday cage, like my spare 3 T suite, but I'm guessing there are no convenient 100dB screens sitting around in Jax, FL.)

 
At July 02, 2016 3:57 PM, Blogger The Neurocritic said...

Great idea! For what was supposedly a prospective study, there were so many variables that were not manipulated (and not reported). It would also be interesting to see if anything unusual happens in ECoG patients... I imagine it's pretty common for them to be waiting around and texting.

 

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