Neurofeedback Training of ADHD Patients – why we need more research

Antti Veikko Petteri Veilahti | Loka 2018 | |

Antti Veikko Petteri Veilahti
PhD,
KELA,
Research Department,
Helsinki

Benjamin Ultan Cowley
PhD, Docent,
Cognitive Science, Department of Digital Humanities,
Faculty of Arts; and Cognitive Brain Research Unit,
Department of Psychology and Logopedics,
Faculty of Medicine; University of Helsinki

Evidence for the efficacy of neurofeedback training (NF) of ADHD patients has been disputed by the most recent ADHD Current Care Guidelines in Finland.1 However, many recent research articles find at least tentative evidence for treatment efficacy, although emphasizing the complexity of NF learning. We argue that research on NF training should be continued, because it seems to benefit some patients, even if not all. The ability to identify in advance those who do actually benefit would greatly enhance the allocation of resources, and increase our understanding of ADHD itself. 

ADHD is an increasingly common cause of young adults’ disability,2 but traditional treatment methods based on medication or behavioral therapy do not appear to address the core aspects of the disorder,3,4,5 or increase professional or academic performance.6,7 

As one alternative treatment method, neurofeedback (NF) training aims to teach subjects to control the state of their own EEG function at various frequency bands. Namely electric activity in the brain occurs as waves with different frequencies, while each frequency band is associated with specific type of brain activity. By teaching subjects to control these brain waves it is believed that they could learn to self-regulate their own neurological activity. 

The first attempts to apply the method specifically to inattentive and conduct-related symptoms emerged in the 1970s.8 This and subsequent work targeted the so-called sensorimotor rhythms (SMR), which are diminished during hyperkinetic behavior; and the theta and beta-rhythms (TB), for which training focuses on increasing beta waves involved in conscious thinking while at the same time decreasing theta-waves that are associated with diminished vigilance.

There is clear evidence for the efficacy of NF training in tackling ADHD. Several non-controlled trials concluded that NF treatment is at least as efficient as stimulant medication.9-12 In their meta-analysis, Arns et al13 conclude that NF training among children with diagnosed ADHD seems to moderately benefit those suffering from hyperactivity, and strongly benefit those suffering from impulsivity and inattention. The problematic question that remains is whether NF is specific, that is, whether the effects emerge from training itself or from other aspects of treatment. NF-related research thus faces both methodological and theoretical challenges.

Current Care Guidelines
Basing on a limited set of meta-analyses that address the specificity of its effects.14-16 ADHD Current Care Guidelines1 do not support the use of NF training on ADHD patients. Yet the significance tests of the previous meta-analyses could be biased by the small sample sizes of prior studies as well as non-standardised clinical practice. Moreover, the conclusion is even more controversial because at least one of the referred studies actually supports the use of NF training on inattentive symptoms,15 whereas in another meta-analysis the effect is almost statistically significant16 (SMD 0,29, 95 % confidence interval -0,02–0,61). Also Cortese et al14 conclude that differences in care practice affect results, since the three studies (which meet the standardisation criteria by Arns et al17) implicated a specific treatment effect.

Even if current, usually non-standardised forms of NF training cannot be recommended as a form of ADHD rehabilitation without reservations, there is both ethical18 and economic demand for new forms of treatment. In particular, the effects of medication require treatment to be continued over extended periods of time, whereas there is at least tentative evidence that the effects of NF training could be sustained over a longer term, even after termination of treatment. Therefore, NF-related research should not be discontinued despite the critical view of the Current Care Guidelines.

Why Current Research on NF Training of ADHD Patients is Limited?
The failure to establish the specificity of NF training could reflect the quality of research rather than NF training itself. The sample sizes are usually low, and studies often consider only the pre- and post-treatment measures rather than studying the entire training period. Even moderate effects would also be significant if they are sustained after the termination of treatment, unlike in standard stimulant-medication treatments where positive effects usually dissipate after termination of treatment.19 Finally, even if not all patients benefit specifically from NF training, some of them might do. Including all patients in the analysis would compromise the treatment effect visible among those patients who actually benefit.

Therefore, instead of taking the Current Care Guidelines at face value, we argue that research on NF training should continue, for the following reasons:
ADHD patients should not be viewed as a uniform group, because different patients respond differently to each possible treatment.
Learning processes associated with NF training should be studied more thoroughly in order to understand and improve the various NF training protocols.
The role of human interaction in NF training should be given more attention.

Reason 1: Performers and Non-Performers
While most studies fail to distinguish between those do or do not benefit from NF training Ie. the so-called ‘performers’ and ‘non-performers’, recently a few studies have started to make this distinction.20 In fact, even a decade ago Doehnert et al21 found that only half of children in an NF study learned to self-regulate, and similar results have been confirmed in the context of alpha-training.22 However, the identification of ‘performers’ is strongly dependent on the chosen protocol.20 In fact, it is not even clear whether learning occurs similarly in different protocols. Future research should focus on those patients that do seem to benefit the most, to seek criteria to identify them in advance, and to further improve the effect of their NF training.

Reason 2: Learning Processes
NF learning has been viewed as being a form of operant conditioning where the subject learns to regulate the underlying EEG trait in a somewhat automatic fashion. In the operant conditioning model, ADHD is viewed as following from an abnormality in the EEG, and treatment aims to normalize the neurophysiological dysfunction.23 It is not always clear what is reinforced, however, because conditioning can also occur on the basis of  more or less irrelevant behaviors during NF training such as breathing, eye movements or muscle activity.

Gevensleben et al24 contrast this ‘conditioning-and-repairing’ hypothesis with the so-called ‘skill-acquisition model’, which requires conscious effort and skill to change the EEG state.25 NF learning is then viewed as “a tool for enhancing specific cognitive or attentional states […]” irrespective of presumed neurophysiological deficits. This implies that motivational, attributional, and personality factors might play a stronger role.24 Strehl,26 in turn, attempts to bridge the two positions, arguing that both operant conditioning and conscious effort might be needed:20 as in Fitts’ theory of motor learning, where cognitive learning is a prerequisite for the successful automation of skills. 

Most studies that have been critical towards the efficacy of NF training have ignored various aspects of the learning process. For example, Schönenberg et al27 presented a sham-controlled trial of NF (sham, equivalent to placebo in a drug trial, has long been cited as the required gold-standard of evidence for NF to provide proper blinding of subjects). However, their study employed an operant conditioning technique based on auto-thresholding, which has been heavily criticized by, e.g. Pigott et al.28 Such aspects have been thoroughly addressed by two empirical research projects that are also among the few existing empirical studies that seek to understand how NF-related skills might be transferred to real-life contexts.29,30 

In future research, there should be more emphasis on the learning processes and particularly how NF-related skills can be transferred to other life contexts. A more thorough understanding of patient learning during NF training could also contribute to our understanding of ADHD itself.

Reason 3: Human Interaction
Also, in addition to the methodological challenges of studying success of NF learning, there might be various reasons for the failure to learn to self-regulate. These include psychological factors like “subjects’ beliefs regarding their ability to gain control over technological devices” and the lack of suitable mental strategies used in the learning process.31 Because psycho-education of such strategies and beliefs could enhance NF learning, it has been suggested that NF training itself could be viewed as a form of behavioral therapy,26 which has methodological implications for studying the efficacy of NF training that are ignored by most critics.24 Human engagement should be viewed as an important part of NF training, rendering it as a particular mode of behavioral therapy, and moving the discussion away from whether feedback of EEG signals alone has the claimed therapeutic effect, since such feedback cannot take place without a behavioural component (as also requested in Schönenberg et al’s32 response to Pigott et al’s28 criticism).

Yhteenveto

Existing evidence for the efficacy of NF training on reducing ADHD core symptoms is mixed and non-specific, with differing effect strengths for different NF protocols and even the different sub-types of ADHD. Future research on NF treatment must deal with three areas:
Difference of performers and non-performers
Learning processes
The role of human engagement
On all grounds we find that the clinical guidelines should reflect the ongoing scientific debate over NF, and not presuppose a conclusion that is not yet supported.

Lähteet

1. ADHD Current Care Guidelines: Review of evidence for biofeedback treatment of ADHD [Article in Finnish]. Duodecim, 2016. http://www.kaypahoito.fi/web/kh/suositukset/suositus?id=nak07651&suositusid=hoi50061, Accessed May 11, 2018. 2. Koskenvuo K Hiilamo H. Participation income can prevent young adults’ marginalization from the workforce. [Article in Finnish.] Sosiaalivakuutus 2017;4:33-35. 3. Firestone, P, Kelly MJ, Goodman JT, Davey J. Differential effects of parent training and stimulant medication with hyperactives: A progress report. Journal of the American Academy of Child Psychiatry 1981;20(1):135-147. 4. Conte R. Attention disorders. In Wong B (ed.) Learning about learning disabilities. New York: Academic Press 1991:60-96. 5. Gaddes WH, Edgell D. Learning Disabilities and Brain Function. New York: Springer-Verlag 1994. 6. Molina BS, Hinshaw SP, Arnold LE, Swanson JM, Pelham WE, Hechtman L, Lu B. Adolescent Substance Use in the Multimodal Treatment Study of Attention-Deficit/Hyperactivity Disorder (ADHD)(MTA) as a Function of Childhood ADHD, Random Assignment to Childhood Treatments, and Subsequent Medication. Journal of the American Academy of Child & Adolecent Psychiatry 2013;52(3):250-263. 7. Van der Oord, S, Prins PJ, Oosterlaan, J, Emmelkamp PM. Efficacy of methylphenidate, psychosocial treatments and their combination in school-aged children with ADHD: a meta-analysis. Clin Psychol Rev 2008;28(5):783-800. 8. Lubar JF, Shouse MN. EEG and behavioral changes in a hyperkinetic child concurrent with training of the sensorimotor rhythm (SMR): A preliminary report. Biofeedback and Self-regulation 1976;1(3):293-306.  9. Fuchs, T, Birbaumer, N, Lutzenberger, W, Gruzelier JH, Kaiser J. Neurofeedback treatment for attention-deficit/hyperactivity disorder in children: A comparison with methylphenidate. Applied Psychophysiology and Biofeedback 2003;28(1):1-12. 10. Monastra VJ, Monastra D M, George S. The effects of stimulant therapy, EEG biofeedback, and parenting style on the primary symptoms of attention- deficit/hyperactivity disorder. Applied Psychophysiology, and Biofeedback 2002;27(4):231-249. 11. Rossiter T. The effectiveness of neurofeedback and stimulant drugs in treating AD/HD: Part I. Review of methodological issues. Applied Psychophysiology, and Biofeedback 2004;29(2):95-112. 12. Rossiter TR, La Vaque TJ. A comparison of EEG biofeedback and psychostimulants in treating attention deficit/hyperactivity disorders. Journal of Neurotherapy 1995;1(1):48–59. 13. Arns M, De Ridder S, Strehl U, Breteler M, Coenen A. Efficacy of neurofeedback treatment in ADHD: the effects on inattention, impulsivity and hyperactivity: a meta-analysis. Clinical EEG and neuroscience 2009;40(3):180-189. 14. Cortese S, Ferrin M, Brandeis D, Holtmann M, Aggensteiner P, Daley D, Sanoths P, Simonoff E, Stevenson J, Stringaris, A, Sonuga-Barke EJ. Neurofeedback for attention-deficit/hyperactivity disorder: meta-analysis of clinical and neuropsychological outcomes from randomized controlled trials. Journal of the American Academy of Child & Adolescent Psychiatry 2016;55(6):444-455. 15. Micoulaud-Franchi JA, Geoffroy PA, Fond G, Lopez R, Bioulac S, Philip P. EEG neurofeedback treatments in children with ADHD: an updated meta-analysis of randomized controlled trials. Frontiers in human neuroscience 2014;8:906. 16. Sonuga-Barke EJ, Brandeis D, Cortese S, Daley D, Ferrin M, Holtmann M, Stevenson J, Danckaerts M, van der Oord S, Döpfner M, Dittmann RW, Simonoff E, Zuddas A, Banaschewski T, Buitelaar J, Coghill D, Hollis C, Konofal E, Lecendreux M, Wong ICK, Sergeant J. Nonpharmacological interventions for ADHD: systematic review and meta-analyses of randomized controlled trials of dietary and psychological treatments. American Journal of Psychiatry 2013;170(3):275-289. 17. Arns M, Heinrich H, Strehl U. Evaluation of neurofeedback in ADHD: the long and winding road. Biological psychology 2014;95:108-115. 18. Singh I. Beyond polemics: Science and ethics of ADHD. Nature Reviews Neuroscience 2008;9(12):957-964. 19. Meisel V, Servera M, Garcia-Banda G, Cardo E, Moreno I. Neurofeedback and standard pharmacological intervention in ADHD: A randomized controlled trial with six-month follow-up. Biological Psychology 2013;94(1):12-21. 20. Alkoby O, Abu-Rmileh A, Shriki O, Todder D. Can we predict who will respond to neurofeedback? A review of the inefficacy problem and existing predictors for successful EEG neurofeedback learning. Neuroscience 2017;378:155-164. 21. Doehnert, M, Brandeis, D, Straub, M, Steinhausen H-C, Drechsler R. Slow cortical potential neurofeedback in attention deficit hyperactivity disorder: Is there neurophysiological evidence for specific effects? Journal of Neural Transmission 2008;115(10):1445-1456. 22. Wan F, Nan W, Vai MI, Rosa A. Resting alpha activity predicts learning ability in alpha neurofeedback. Frontiers in Human Neuroscience 2014;8:500. 23. Gevensleben H, Holl B, Albrecht B, Schlamp D, Kratz O, Studer P, Wangler S, Rothenberger A, Moll GH, Heinrich H. Distinct EEG effects related to neurofeedback training in children with ADHD: A randomized controlled trial. International Journal of Psychophysiology 2009;74(2):149-157. 24. Gevensleben H, Moll GH, Rothenberger A, Heinrich H. Neurofeedback in attention-deficit/hyperactivity disorder – different models, different ways of application. Frontiers in human neuroscience 2014;8:846. 25. Bakhshayesh A R, Hansch S, Wyschkon A, Rezai MJ, Esser G. Neurofeedback in ADHD: a single-blind randomized controlled trial. Eur. Child Adolesc. Psychiatry 2011;20:481-491. 26. Strehl U. What learning theories can teach us in designing neurofeedback treatments. Frontiers in human neuroscience 2014;8:894. 27. Schönenberg, M, Wiedemann, E, Schneidt, A, Scheeff, J, Logemann, A, Keune PM, Hautzinger M. Neurofeedback, sham neurofeedback, and cognitive-behavioural group therapy in adults with attention-deficit hyperactivity disorder: a triple-blind, randomised, controlled trial. The Lancet Psychiatry 2017;4(9):673-684. 28. Pigott HE, Trullinger, M, Harbin, H, Cammack, J, Harbin, F, Cannon R. Confusion regarding operant conditioning of the EEG. The Lancet Psychiatry 2017;4(12):897. 29. Janssen TW, Bink M, Weeda WD, Geladé K, van Mourik R, Maras A, Oosterlaan J. Learning curves of theta/beta neurofeedback in children with ADHD. European Child & Adolescent Psychiatry 2017;26(5):573-582. 30. Cowley, B, Holmström, É, Juurmaa, K, Kovarskis, L, Krause CM. Computer enabled neuroplasticity treatment: a clinical trial of a novel design for neurofeedback therapy in adult ADHD. Frontiers in Human Neuroscience 2016:10:205. 31. Kober SE, Witte M, Ninaus M, Neuper C, Wood G. Learning to modulate one’s own brain activity: the effect of spontaneous mental strategies. Front Hum Neurosci 2013;7:695. 32. Schönenberg M, Wiedemann E, Schneidt A, Scheeff J, Logemann A, Keune PM, Hautzinger M. Confusion regarding operant conditioning of the EEG–Authors’ reply. The Lancet Psychiatry 2017;4(12):897-898.