For a num­ber of rea­sons, there remains an impor­tant need to develop research sup­ported treat­ments for ADHD in addi­tion to med­ica­tion and behav­ior therapy.

Regard­ing med­ica­tion, not all chil­dren ben­e­fit from tak­ing it, some expe­ri­ence intol­er­a­ble side effects, and many con­tinue to strug­gle even when med­ica­tion pro­vides some ben­e­fit. Behav­ior ther­apy can be dif­fi­cult for par­ents and teach­ers to con­sis­tently imple­ment, and often helps but does not elim­i­nate a child’s behav­ioral prob­lems. Fur­ther­more, nei­ther treat­ment yields pos­i­tive changes that per­sist when the treat­ment is dis­con­tin­ued. Finally, despite numer­ous stud­ies doc­u­ment­ing the short– and inter­me­di­ate term ben­e­fits of these treat­ments, evi­dence of their impact on children’s long-term suc­cess is less evident.

One rel­a­tively recent devel­op­ment in the realm of ADHD treat­ments is work­ing mem­ory train­ing. Work­ing mem­ory (WM) refers to the abil­ity to hold and manip­u­late infor­ma­tion in mind for sub­se­quent use and is crit­i­cally impor­tant for a vari­ety of learn­ing activ­i­ties. For exam­ple, when a child is asked ques­tions about a story he has read, work­ing mem­ory allows the child to retain and review the story infor­ma­tion in mind to answer the ques­tions. In doing men­tal math, work­ing mem­ory is used to hold the dig­its in mind and manip­u­late them, e.g., add or sub­tract, to gen­er­ate the answer.

Work­ing mem­ory is also impor­tant in the con­trol of atten­tion and is a strong pre­dic­tor of aca­d­e­mic suc­cess. It is defi­cient in many indi­vid­u­als with ADHD; in fact, some researchers believe that work­ing mem­ory deficits are cen­tral to ADHD and under­line the inat­ten­tive and hyperactive-impulsive behav­ior that char­ac­ter­izes the dis­or­der. You can learn more about work­ing mem­ory and ADHD here.

Sev­eral years ago I reviewed a study of work­ing mem­ory train­ing for ADHD that yielded promis­ing find­ings. Chil­dren were ran­domly assigned to receive either high inten­sity (HI) or low inten­sity WM train­ing. The HI treat­ment involved per­form­ing com­put­er­ized WM tasks, e.g., remem­ber­ing the sequence in which lights appeared in dif­fer­ent por­tions of a grid, recall­ing a sequence of num­bers in reverse order, where the dif­fi­culty level was reg­u­larly adjusted to match the child’s per­for­mance by increas­ing or decreas­ing the items to be recalled. This is described below as ‘adap­tive’ train­ing because the dif­fi­culty level adapts to match the child’s capa­bil­ity. In this train­ing con­di­tion, chil­dren are con­sis­tently chal­lenged to expand their work­ing mem­ory capacity.

In the LI con­di­tion, the tasks were sim­i­lar but the dif­fi­culty remained low through­out, i.e., the num­ber of items did not increase when chil­dren responded cor­rectly. For these chil­dren, their work­ing mem­ory capac­ity was not con­sis­tently chal­lenged and was not expected to grow as a result. This served as the con­trol condition.

Train­ing was con­ducted 5 days a week over a 5 week period; each ses­sion lasted approx­i­mately 30 to 40 min­utes. Fol­low­ing treat­ment, chil­dren who received high inten­sity train­ing showed stronger work­ing mem­ory per­for­mance than chil­dren in the con­trol con­di­tion; these gains were evi­dent on work­ing mem­ory tasks that had not been trained and remained evi­dent 3 months after train­ing ended. Fur­ther­more, only chil­dren who received high inten­sity train­ing showed sig­nif­i­cant declines in par­ent rat­ings of ADHD symp­toms showed sig­nif­i­cant and mean­ing­ful declines for chil­dren. These declines remained evi­dent 3 months later.

Although these were very pos­i­tive find­ings, a lim­i­ta­tion was that no treat­ment effects were found for teacher rat­ings of children’s behav­ior. Thus, there was no indi­ca­tion that ben­e­fits observed by par­ents, and mir­rored in the work­ing mem­ory assess­ments, had gen­er­al­ized to the class­room. Given the need to improve behav­ior at school for chil­dren with ADHD, it is con­cern­ing that a sim­i­lar pat­tern of find­ings, i.e., train­ing related gains in work­ing mem­ory per­for­mance and in par­ent rat­ings of children’s behav­ior, but less evi­dence of ben­e­fits observed by teach­ers, has emerged in sub­se­quent studies.

Newly Pub­lished Study

A study pub­lished online recently in Neu­rother­a­peu­tics [Green et. al., (2012). Will work­ing mem­ory train­ing gen­er­al­ize to improve off-task behav­ior in chil­dren with attention-deficit/hyper­ac­tiv­ity dis­or­der? Neu­rother­a­peu­tics. DOI 10.1007/s13311-012‑0124-y] is encour­ag­ing in that it pro­vides that strongest evi­dence to date that ben­e­fits from work­ing mem­ory train­ing can gen­er­al­ize to aca­d­e­mic settings.

Par­tic­i­pants were 26 chil­dren (18 males; ages 7 to 14 years old) who were ran­domly assigned to receive adap­tive work­ing mem­ory train­ing or the low inten­sity con­trol train­ing. Ten chil­dren were on med­ica­tion and remained on meds dur­ing the study; this was con­trolled for in the analyses.

The train­ing pro­gram used was Cogmed Work­ing Mem­ory train­ing (the researchers had no affil­i­a­tion with Cogmed). The stan­dard train­ing pro­to­col of 5 ses­sions per week over 5 weeks was employed. Per stan­dard Cogmed pro­ce­dures, train­ing was done at home and was mon­i­tored remotely by a qual­i­fied coach to help ensure the pro­to­col was followed.

The main study out­come was children’s behav­ior dur­ing the Restricted Aca­d­e­mic Sit­u­a­tions Task (RAST). Dur­ing the RAST, which takes place in a lab set­ting, chil­dren are instructed to com­plete a series of aca­d­e­mic work sheets for 15 min­utes, and not to leave their seat, or touch any of the toys or games in the room, dur­ing that time. The child is left alone to com­plete the work and their behav­ior is observed from behind a one-way mir­ror. The child’s behav­ior is coded for the amount of off task behav­ior, e.g., look­ing away from the paper, get­ting out of his or her seat, fid­get­ing, vocal­iz­ing, or play­ing with objects unre­lated to the task.

The task thus allows for highly con­trolled behav­ioral obser­va­tions and is fre­quently used to eval­u­ate the effect of med­ica­tion on ADHD behav­iors in phar­ma­ceu­ti­cal tri­als. It is sen­si­tive to moment to moment off task behav­ior that a teacher or par­ent might not detect.

The main ques­tion asked in this study was whether chil­dren who received adap­tive train­ing would show less off task behav­ior dur­ing the RAST than chil­dren in the con­trol con­di­tion. If so, it would indi­cate a pos­i­tive treat­ment effect of work­ing mem­ory train­ing that gen­er­al­ized to a set­ting highly rel­e­vant to behav­ior in school. Obser­va­tions of treat­ment and con­trol chil­dren was made by a trained observer who did not know which group — adap­tive treat­ment or con­trol — each child was in.

In addi­tion to the RAST, children’s work­ing mem­ory per­for­mance on tasks that dif­fered from those used in train­ing (the Work­ing Mem­ory Com­pos­ite from the WISC-IV) and par­ent behav­ior rat­ings were obtained.

Results

Impact on Work­ing Mem­ory - Con­sis­tent with what has been reported in prior work­ing mem­ory train­ing stud­ies, chil­dren receiv­ing adap­tive train­ing showed a sig­nif­i­cant increase in the work­ing mem­ory score on the WISC-IV after train­ing; chil­dren in the con­trol con­di­tion did not.

Rat­ing scales - Both groups showed a decline on par­ents’ rat­ings of ADHD behav­iors and this did not dif­fer between the groups. Base­line scores for chil­dren in the adap­tive train­ing group were lower than in the con­trol group so they may have had less room for improvement.

Behav­ior dur­ing the RAST - The main out­come mea­sure from the RAST was the amount of off task behav­ior, i.e., look­ing away from the work sheet rather than focus­ing on it, dur­ing the 15 minute seat work period. At base­line, scores for each group were equiv­a­lent. Fol­low­ing train­ing, when the RAST was read­minin­stered, off-task behav­ior for chil­dren in the con­trol group remained at their base­line level. For the adap­tive train­ing group, there was a pro­nounced and sta­tis­ti­cally sig­nif­i­cant decline. Adap­tively trained chil­dren were also less likely to play with objects dur­ing the task. Dif­fer­ences in the other behav­ior cat­e­gories — fid­get­ing, leav­ing the seat, and vocal­iz­ing — were not significant.

Sum­mary and Implications

This is an impor­tant study — both for Cogmed Work­ing Mem­ory Train­ing specif­i­cally and the cog­ni­tive train­ing field in gen­eral. The results strongly sug­gest that work­ing mem­ory train­ing can yield reduc­tions in off task behav­ior dur­ing aca­d­e­mic work for chil­dren with ADHD. This has not been pre­vi­ously demon­strated and begins to address an impor­tant gap in the research base on work­ing mem­ory train­ing for ADHD, i.e., the lim­ited indi­ca­tion of train­ing effects that gen­er­al­ize to the class­room. While the RAST reflects a con­trolled obser­va­tion set­ting rather than an actual class­room, behav­ior dur­ing the RAST does cor­re­late with in class behav­ior. And, it is a fre­quently used and accepted mea­sure for deter­min­ing med­ica­tion treat­ment effects for ADHD.

The study has sev­eral strengths includ­ing a care­fully diag­nosed sam­ple, the use of ran­dom assign­ment, an appro­pri­ate con­trol group, the use of mul­ti­ple out­come mea­sures, and observers who were blind to children’s treat­ment assign­ment. These are all key ele­ments of a care­fully designed inter­ven­tion trial.

As with any sin­gle study, there are also lim­i­ta­tions to note. Key among these is a rel­a­tively small sam­ple size. Thus, repli­ca­tion with a larger sam­ple would cer­tainly be war­ranted. And, although the RAST pro­vides a valid and highly con­trolled set­ting to observe behav­ior, future stud­ies should also include obser­va­tions of children’s behav­ior in their actual class­room. Although this makes for a more com­plex study, the class­room is ulti­mately the set­ting where increases in focused, on task behav­ior dur­ing aca­d­e­mic work needs to occur. Finally, this study did not fol­low par­tic­i­pants beyond the end of treat­ment so the dura­tion of ben­e­fits observed is not known.

These lim­i­ta­tions not with­stand­ing, the authors have pre­sented impor­tant new data on the poten­tial ben­e­fits of work­ing mem­ory train­ing by demon­strat­ing gen­er­al­iza­tion of train­ing ben­e­fits to a rel­e­vant set­ting for aca­d­e­mic work. Given the grow­ing inter­est in work­ing mem­ory train­ing — and other forms of cog­ni­tive train­ing — it is likely that results from a num­ber of addi­tional stud­ies on these approaches will become avail­able over the next sev­eral years.

– Dr. David Rabiner is a child clin­i­cal psy­chol­o­gist and Direc­tor of Under­grad­u­ate Stud­ies in the Depart­ment of Psy­chol­ogy and Neu­ro­science at Duke Uni­ver­sity.  His research focuses on var­i­ous issues related to ADHD, the impact of atten­tion prob­lems on aca­d­e­mic achieve­ment, and atten­tion train­ing.  He also pub­lishes Atten­tion Research Update, a com­pli­men­tary online newslet­ter that helps par­ents, pro­fes­sion­als, and edu­ca­tors keep up with the lat­est research on ADHD.
Pre­vi­ous arti­cles by Dr. Rabiner:

• Study: Promis­ing New Neu­rocog­ni­tive Inter­ven­tion for Preschool­ers with ADHD (TEAMS)
• Study: Fam­i­lies’ Per­spec­tives on ADHD and its Treatment
• Self-Regulation and Barkley’s The­ory of ADHD

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