short-term-memory

Work­ing mem­o­ry (WM) is the cog­ni­tive sys­tem respon­si­ble for the tem­po­rary stor­age and manip­u­la­tion of infor­ma­tion and plays an impor­tant role in both learn­ing and focus­ing atten­tion. Con­sid­er­able research has doc­u­ment­ed that many chil­dren and adults with ADHD have WM deficits and that this con­tributes to dif­fi­cul­ties asso­ci­at­ed with the dis­or­der. For an excel­lent intro­duc­tion to the role of WM deficits in ADHD, click here.

A sim­ple exam­ple illus­trates the impor­tance of WM for par­tic­u­lar aca­d­e­m­ic tasks. Try adding 3 and 9 in your head. That was prob­a­bly easy for you. Now try­ing adding 33 and 99. That was prob­a­bly more dif­fi­cult. Final­ly, try adding 333 and 999. This is quite chal­leng­ing for most adults even though each cal­cu­la­tion required is triv­ial­ly easy. The chal­lenge occurred because you need to store infor­ma­tion — the sum of 3+9 in the one’s col­umn and then ten’s col­umn — as you process the remain­ing part of the prob­lem, i.e., 3+9 in the hun­dred’s col­umn, and this taxed your WM. If your WM capac­i­ty was exceed­ed, you could not com­plete the prob­lem successfully.

This sim­ple prob­lem also illus­trates the dif­fer­ence between short-term mem­o­ry (STM) and WM. Short-term mem­o­ry sim­ply involves retain­ing infor­ma­tion in mind for short peri­ods of time, e.g., remem­ber­ing that the prob­lem you need to solve is 333+999. Work­ing mem­o­ry, in con­trast, involves men­tal­ly manip­u­lat­ing — or ‘work­ing’ with — retained infor­ma­tion and comes into play in a wide range of learn­ing activ­i­ties. For exam­ple, to answer ques­tions about a sci­ence chap­ter, a child not only has to cor­rect­ly retain fac­tu­al infor­ma­tion but must men­tal­ly work with that infor­ma­tion to answer ques­tions about it. Thus, when a child’s WM capac­i­ty is low rel­a­tive to peers, aca­d­e­m­ic per­for­mance is like­ly to be com­pro­mised in mul­ti­ple areas.

Because WM deficits play an impor­tant role in the strug­gles expe­ri­enced by many indi­vid­u­als with ADHD, it is impor­tant to con­sid­er how dif­fer­ent inter­ven­tions address this aspect of the dis­or­der. In this study, the authors were inter­est­ed in com­par­ing the impact of Work­ing Mem­o­ry Train­ing and stim­u­lant med­ica­tion treat­ment on the WM per­for­mance of chil­dren diag­nosed with ADHD.

Par­tic­i­pants were 25 8–11 year-old chil­dren with ADHD (21 boy and 4 girls) who were being treat­ed with stim­u­lant med­ica­tion. Chil­dren’s mem­o­ry per­for­mance was assessed on 4 occa­sions using the Auto­mat­ed Work­ing Mem­o­ry Assess­ment (AWMA), a com­put­er­ized test that mea­sures ver­bal short-term mem­o­ry, ver­bal work­ing mem­o­ry, visuo-spa­tial short-term mem­o­ry, and visuo-spa­tial work­ing memory.

At time 1, the assess­ment was con­duct­ed when chil­dren had been off med­ica­tion for at least 24 hours. The sec­ond assess­ment occurred an aver­age of 5 months lat­er and when chil­dren were on med­ica­tion. The third assess­ment occurred after chil­dren had com­plet­ed 5 weeks of Cogmed Work­ing Mem­o­ry Train­ing using the stan­dard train­ing pro­to­col (see below). The final assess­ment occurred approx­i­mate­ly 6 months after train­ing had end­ed. This design enabled the researchers to make the fol­low­ing comparisons:

- WM per­for­mance on med­ica­tion vs. off med­ica­tion (T1 vs T2)
— WM per­for­mance on med­ica­tion vs. after train­ing (T2 vs. T3)
— WM per­for­mance imme­di­ate­ly after train­ing end­ed vs. 6 months fol­low­ing train­ing (T3 vs. T4)

This final com­par­i­son pro­vid­ed infor­ma­tion on whether any ben­e­fits pro­vid­ed by the train­ing had endured.

In addi­tion to mea­sur­ing STM and WM at each time point, mea­sures of IQ were col­lect­ed at times 1, 2, and 3.

- Work­ing Mem­o­ry Train­ing -

WM train­ing was con­duct­ed using the stan­dard Cogmed train­ing pro­to­col with each child com­plet­ing 20–25 train­ing ses­sions with­in a 25 day peri­od. The train­ing requires the stor­age and manip­u­la­tion of sequences of ver­bal, e.g., repeat­ing back a sequence of dig­its in reverse order, and/or visuo-spa­tial infor­ma­tion, e.g., recall­ing the loca­tion of objects on dif­fer­ent por­tions of the com­put­er screen.

Dif­fi­cul­ty lev­el is cal­i­brat­ed on a tri­al by tri­al basis so the child is always work­ing at a lev­el that close­ly match­es their per­for­mance. For exam­ple, if a child suc­cess­ful­ly recalled three dig­its in reverse order, on the next tri­al he had to recall four. When a tri­al was failed, the next tri­al was made eas­i­er by reduc­ing the num­ber of items to be recalled. This method of ‘adap­tive train­ing’ is thought to be a key ele­ment because it requires the child to ‘stretch’ their WM capac­i­ty to move through the program.

- Results -

- Impact of Short-Term Mem­o­ry and Work­ing Mem­o­ry -

Med­ica­tion vs. no med­ica­tion — When test­ed on med­ica­tion, [Read more…] about Com­par­ing Work­ing Mem­o­ry Train­ing & Med­ica­tion Treat­ment for ADHD