Biofeedback Association for Applied Psychophysiology & Biofeedback Volume 34, Issue 3, pp. 99-105 www.aapb.org SPECIAL ISSUE Improving Attention in Adults and Children: Differing Electroencephalography Profiles and Implications for Training Michael Thompson, MD, DPsych, and Lynda Thompson, PhD, CPsych ADD Centres Ltd. and the Biofeedback Institute of Toronto, Canada Keywords: adult ADHD, EEG patterns, ADHD subtypes, EEG assessment, neurofeedback Retrospective examination of electroencephalography children to ascertain whether these EEG patterns differed (EEG) assessment findings demonstrates that adult and, if they did, whether the differences corresponded to clients who present with attention deficit disorder differences in clinical presentation. Clinical experience require a somewhat different approach than that com- spanning more than 12 years at the ADD Centre/ monly used with children. Initial findings based on 1- Biofeedback Institute of Toronto suggested that adults channel samples at Cz were reviewed and supplemented with attentional problems (attention deficit hyperactivity with observations based on 19-channel samples. Two disorder [ADHD], inattentive or combined types) often main EEG patterns were found in adults. One pattern, had more complex presentations than children did and that with elevated theta-beta ratios, corresponds to the most the EEG patterns correspondingly showed more than one common pattern seen in children. The second pattern is deviation from normal patterns. The subjects for this pilot characterized by high-amplitude, high-frequency beta, study were consecutive clients whose EEGs were recorded which may include beta spindling at frequencies above and assessed in one of seven training offices of the ADD 20 Hz, either with or without excess theta. The two Centre. This office was often used for a second EEG assess- groups present with different symptom pictures: Those ment in children (a reliability check) and was also the with beta spindling have anxiety in addition to prob- office where the majority of adults coming to the center lems sustaining attention. Case examples highlight dif- had assessments done, because stress assessments incorpo- fering assessment findings and appropriate interven- rating regular biofeedback modalities as well as EEG tions. Regardless of age, each client is unique, and the assessments and training were done on this computer. intervention needs to be customized. Most children are initially assessed in a different office, and those who have a classic pattern of high theta-beta Method ratios are not usually given a second EEG assessment, The goal of this pilot study was to investigate electroen- which accounts for the higher number of adults as com- cephalography (EEG) patterns in a sample of adults and pared to children in this review. Thus, the subjects for this Table. Electroencephalography ratios referenced in this study Descriptive Label Frequency Range (Hz) Amplitude ratios (ratios of amplitudes in microvolts) Hi-beta–SMR 26-34/13-15 Mid-beta–SMR 21-25/13-15 Theta–beta 4-8/16-20 Thalpha–beta 6-10/16-20 Biofeedback Power ratios (ratios of power, defined as amplitude squared) Theta power/beta power (4-8)2/(13-21)2 ⎪ Note. Sensorimotor rhythm (SMR) = 13–15 for adults. 2006 Fall 99 Improving Attention in Adults and Children study comprised 154 adults (aged 18 to 65 years) and 92 than 1.5 was used to identify subjects who would be children (aged 6 to 17 years) seen consecutively in one placed in what we would call the hi-beta ADHD group. office at the ADD Centre. EEG data collected during each After the first results were calculated, an additional person’s initial session were reviewed. In addition to sample including most of the adults was taken, and two clients, on the same computer, there were 25 EEG records different ratios were calculated: 19-22/11-12 Hz and 23 from adults who were not clinical cases. These persons -35/13-15 Hz. The reason for this change was that ten- were used as a comparison group. This group contained sion and anxiety were sometimes clinically correlated professionals who were taking a training course in neuro- with a decrease in hi-alpha (11-12 Hz) and an increase in feedback, ADD Centre staff, and two individuals who did beta somewhere between 19 and 22 Hz. In addition, indi- not display inattention but came to optimize performance. vidual clients demonstrated spindling beta at 24, 25, or These individuals could be broadly described as calm, 35 Hz, which they subjectively associated with negative thoughtful, and successful. Interestingly, all their EEGs ruminations. This activity was missed by the original hi- demonstrated low theta-beta ratios and low hi-beta–senso- beta range of 26 to 34 Hz. rimotor rhythm ratios (SMR). The Table defines each of the EEG ratios referenced in this document quantitatively, Results showing the frequency range for each term in the ratio. In the adult population, two major groups emerged. The first group was labeled “the Drifters.” This group com- Hypotheses prised 74% of the adults with attentional problems (95 The main hypothesis, based on clinical observations, was of 129). In 89 cases, these adults demonstrated high that some adults with ADHD symptoms exhibit a “busy theta-beta ratios using both theta-beta ratios (in micro- brain” that correlates with high-amplitude bursts of hi- volts) and theta power–beta power ratios (in picowatts). beta activity, a corresponding dip in SMR, and a hi- Indeed, 80% of this group were more than two standard beta–SMR ratio greater than 1.5. A second hypothesis deviations above the norms from the multisite study for was that this pattern would be rare in children except theta-beta power ratios (Monastra et al., 1999). This those with high anxiety and/or Asperger’s syndrome. group contained a subgroup in which high theta-beta Most children were expected to fit the high theta-beta ratios were combined with elevated hi-beta–SMR ratios. power ratios that have been studied by Lubar for decades These individuals can tune out in two ways: drifting off and for which there are published norms (Monastra et al., or ruminating. This subgroup had 45 cases. Thus, 51% 1999). of the high theta-beta ratio group also had elevated hi- Other researchers have noted, in addition to children beta–SMR ratios. In six cases within the Drifters group, with excess theta, an ADHD sub-type with excess beta just the theta-beta ratio was high, and none of these (Clarke et al., 2001). individuals had elevated hi-beta–SMR ratios. Ratios were calculated for theta-beta, thalpha-beta, The second group was labeled “the Busy Brains.” This Lubar’s theta power–beta power ratio, mid-beta–SMR, group was composed of 30 adults who showed only and hi-beta–SMR. The Monastra-Lubar cutoff scores for high-amplitude hi-beta–SMR ratios without theta-beta ADHD of 1.5 standard deviations above normal for theta being high. The definition of high ratio was based on power–beta power ratios were used to categorize clients clinical observations and arbitrarily set at greater than into the high-theta ADHD group. In addition, a micro- 1.5 as a cutoff score for hi-beta/SMR ratios (>1.55 works volt ratio greater than 2.2, which we based on our clini- for 26-35/13-15 Hz). Twenty-six adults met this criteri- cal observations, was used as an ADHD indicator in on. In four cases, this ratio was not high, but 21-25/13- adults, for either theta-beta or thalpha-beta ratios. 15 Hz was >1. We found our most severe clinical cases (Lubar has noted when giving workshops that whereas had the highest ratios. Of the 121 cases reviewed that children usually show high theta, adults may show high showed high theta-beta and/or elevated hi-beta–SMR thalpha; hence the inclusion of the 6-10 range.) All the ratios, 22% showed only elevated hi-beta compared to children were previously diagnosed as ADHD, but some SMR. (The elevated hi-beta–SMR ratio group turned also demonstrated comorbidity, such as meeting the out to be virtually the same percentage of clients when a diagnostic criteria for other problems such as Asperger’s 23-35/13-15 Hz ratio was calculated.) With the excep- syndrome. All adults complained of difficulties with tion of a small number of optimal performance candi- Biofeedback attention span and impulsivity that interfered with mul- dates and athletes, the large majority of the high 26- ⎪ tiple aspects of their lives. A hi-beta–SMR ratio greater 34/13- 15Hz clients complained of intrusive, negative, Fall 2006 Fall 100 Thompson, Thompson circular thoughts or ruminations, which they felt were gle-channel EEG assessment was supplemented with a the reason they could not concentrate. This tendency to 19-lead assessment, and the results were analyzed using have a negative inner dialogue was responsible for their low-resolution brain electromagnetic tomography questionnaire responses meeting ADHD criteria and for (LORETA), a statistical procedure performing three- their poor results on the Test of Variable Attention dimensional projections to identify cortical sources for (TOVA) and the Integrated Visual Auditory (IVA) con- patterns measured with surface EEG. The origin of these tinuous performance tests. We should note, at this junc- bursts of beta proved to be the anterior cingulate ture, that we have seen occasional professionals who are (Brodmann Area 24), and some of the major clinical very successful, who comment that their brains are symptoms in these cases were anxiety, panic, and/or always “going at 100 mph,” and who show a high hi- obsessive compulsive disorder (OCD). Spindling beta beta–SMR ratio. It is for this reason that we have called was also seen in people with autistic spectrum disorders this group “the Busy Brains” and not given it a negative including Asperger’s syndrome.