CRITICALLY APPRAISED PAPER (CAP) Söderlund, G. B. W., Björk, C., & Gustafsson, P. (2016). Comparing auditory noise treatment with stimulant medication on cognitive task performance in children with attention deficit hyperactivity disorder: Results from a pilot study. Frontiers in Psychology, 7, 1331. https://doi.org/10.3389/fpsyg.2016.01331 CLINICAL BOTTOM LINE Executive function and working memory deficits among children with attentiondeficit/hyperactivity disorder (ADHD) can affect their occupational performance at home and at school. Occupational therapists often recommend environmental modifications to improve performance. This case-control study examined the effect of white noise delivered at 80 db through headphones to children ages 9 15 with ADHD. The authors compared the children s performance during standardized tests of verbal memory, visual spatial working memory, and vigilance-based working memory processing with noise versus with stimulant medications. The study results provide early support for the use of white noise during verbal memory and visual spatial working memory tasks but not for tasks that require vigilance and working memory processing. Study limitations include convenience sampling and lack of blinding. The authors did not report the validity or reliability of the measures used, and the measures were not comparable to home or school activities. Generalizability is limited by age and academic performance. Children with ADHD had a mean rating of average for school performance, determined by their teachers. Further research is warranted to explore the intervention s application to occupational performance and address the limitations in this study. RESEARCH OBJECTIVE(S) To examine the effects of white noise versus stimulant medication on a cognitive test battery To examine the effects of white noise on the scores of typically developing children (TDCs) on the same measures. DESIGN TYPE AND LEVEL OF EVIDENCE Level II, case control 1
PARTICIPANT SELECTION How were participants recruited and selected to participate? The authors used a convenience sample of children with ADHD and TDCs. Children with ADHD were recruited through a national organization. TDCs were approached by their school headmaster. The authors used a purposeful selection to match the TDCs with the children with ADHD on the basis of age, gender, and teacher-reported school performance. Inclusion criteria: ADHD group: Diagnosis of ADHD per Diagnostic and Statistical Manual of Mental Disorders (5th ed.) criteria before the study Prescribed stimulant medication TDC group: Rated as average or above average on school performance by their teacher Score of less than 5 on an ADHD symptom criteria rating scale (36 54 indicates ADHD) Exclusion criteria: N/A PARTICIPANT CHARACTERISTICS N= 40 #/ % Male: 27/(68%) #/ % Female: 13/(32%) Ethnicity: All participants lived in Sweden; ethnicity not reported Disease/disability diagnosis: ADHD group: 13 diagnosed with ADHD, combined type 7 with ADHD, inattentive type TDC group: 20 typical children INTERVENTION AND CONTROL GROUPS Group 1: ADHD group 2
Brief description of the intervention White noise was provided through headphones at a level of 80 db, and a cognitive battery was conducted on a 15-in. laptop. Children completed a cognitive battery with and without the noise; condition order was randomized. Children completed the batteries twice: 1 day on medication, and 1 day off medication. How many participants in the group? Where did the intervention take place? Who delivered? How often? For how long? 20 children with ADHD At the participants school, between 9 a.m. and 11 a.m. All instructions and tasks were completed on a computer. The intervention was completed on 2 days 1 day on stimulant medications, and 1 day off medications (for at least 24 hours) with 3 6 days between. Each task took 5 minutes, with the time counterbalanced between the noise and no-noise conditions. NA Group 2: TDC group Brief description of the intervention How many participants in the group? Where did the intervention take place? Who delivered? White noise was provided through headphones at a level of 80 db, and a cognitive battery was conducted on a 15-in. laptop. Children completed a cognitive battery with and without the noise; the condition order was randomized. Children completed the batteries twice. 20 TDCs At the participants school, between 9 a.m. and 11 a.m. All instructions and tasks were completed on a computer. How often? The intervention was completed on 2 days. Each task took 5 minutes, with the time counterbalanced between the noise and nonoise conditions. For how long? NA INTERVENTION BIASES Contamination: Co-intervention: The computer program controlled whether white noise or no additional noise was playing during each task, which decreased the risk of contamination. 3
The intervention period was brief, which decreased effects of any cooccurring remediation interventions. Timing of intervention: Site of intervention: YES NO The researchers used a washout period of at least 24 hours before the unmedicated trials to ensure that medication was no longer in the participants bloodstream. Interventions were brief, which decreased the risk of maturation effects. The researchers counterbalanced noise and no-noise conditions during each task to decrease order effects. The authors counterbalanced the order of medication versus no-medication conditions between the 2 testing days across participants to decrease any order-based learning effects. Interventions were conducted at each student s school. Environmental conditions were not described. Lighting, background noises, and temperature are examples of how the environments might have been different. Use of different therapists to provide intervention: Intervention was provided through a computer program; the same researcher collected data for all participants. Baseline equality: Participants were matched for age, gender, and academic performance. MEASURES AND OUTCOMES (Only on measures relevant to occupational therapy practice) Measure 1: Word recall Name/type of Word recall measure used: What outcome is measured? Is the measure reliable (as reported in the article)? Is the measure valid (as reported in the article)? Verbal episodic memory Lists of 12 nouns were provided verbally and visually at a rate of one word every 5 seconds. Each list included six low-frequency and six highfrequency words, and lists were matched for word frequency, word length, and syllable number. Immediately after seeing each list, participants were asked to recall the words in any order. NO Not Reported NO Not Reported 4
When is the measure used? Tasks were completed during each intervention condition. Measure 2: Span-board task Name/type of Span-board task measure used: What outcome is Recall of dots on a 4 4 grid: visuospatial working memory measured? Participants were shown dots appearing and disappearing on a grid every 3 seconds. They were instructed to click the locations the dots had appeared on the grid, in sequential order. The number of dots increased until the participants made errors on two consecutive trials for that Is the measure reliable as reported in the article? Is the measure valid as reported in the article? When is the measure used? number. NO Not Reported NO Not Reported Tasks were completed during each intervention condition. Measure 3: Verbal 2-back task Name/type of Verbal 2-back task measure used: What outcome is Verbal working memory measured? Thirty words were presented visually, one at a time, every 4.25 seconds. Participants were instructed to press a button every time a word matched Is the measure reliable as reported in the article? Is the measure valid as reported in the article? When is the measure used? MEASUREMENT BIASES the one provided two words prior. NO Not Reported NO Not Reported Tasks were completed during each intervention condition. Were the evaluators blind to treatment status? Evaluators were not blind to treatment condition or diagnosis. Was there recall or memory bias? Counterbalanced order of presentation was used, and different word lists were used in each session. 5
RESULTS Effect of White Noise Versus No Additional Noise on Memory Tasks There were differences between the white noise and no-noise conditions, without regard to participant group (ADHD or TDC). The authors found a small main effect for noise condition, F(1, 38) = 5.71, p =.022, ƞ² =.131, using a mixed analysis of variance (ANOVA) assessed variance based on group (ADHD or TDC), noise condition, and task. Among children with ADHD, white noise improved performance on memory tasks. The authors found a moderate main effect for noise, F(1, 19) = 16.64, p =.001, ƞ² =.467, using an ANOVA to assess noise condition, medication condition, and task. Among children with ADHD, the noise condition had differing impacts on the three tasks. The authors found a moderate effect size on an interaction between noise condition and task, F(2, 18) = 11.40, p =.003, ƞ² =.375, using an ANOVA for noise condition, medication condition, and task in the ADHD group. They used post hoc analyses to determine differences between the task conditions. Among children with ADHD, white noise improved span-board task performance. The authors conducted paired t tests for noise versus no noise while participants were unmedicated, t(19) = 3.18, p =.005, and medicated, t(19) = 2.28, p =.034. The interaction between noise and medication was not statistically significant, F(1, 19) = 3.51, p =.077. Among children with ADHD, white noise improved word recall task performance. The authors conducted paired t tests for noise versus no noise, t(19) = 4.92, p <.0005, while participants were unmedicated. Noise condition did not affect performance on the verbal 2-back task. There was no main effect of noise on ADHD (p = 0.136) and no interaction between group and noise. Comparison of Effect for Children With ADHD Versus TDCs The authors found no statistically significant differences when comparing groups across noise conditions, without regard to task. They found no statistically significant interactions between group and noise, F(1, 38) = 3.10, p =.086, using a mixed ANOVA assessed variance based on group (ADHD or TDC), noise condition, and task. This analysis did not account for whether the children with ADHD were on or off medication. The authors used post hoc analyses to further explore group differences. TDCs scored higher on the span-board task than unmedicated children with ADHD when no additional noise was presented. An independent t test showed that the TDC group performed better than the ADHD group on the span-board task without noise, t(38) = 2.52, p =.016, but not during the no-noise condition, t(38) = 0.68, p =.504. Mean scores show that TDCs scored slightly but insignificantly lower during the noise condition as compared with the no-noise condition. Children with ADHD scored significantly higher during the noise condition as compared with the no-noise condition, whether on medications (p =.034) or off medications (p =.005). TDCs scored higher on the word recall task than unmedicated children with ADHD when no additional noise was presented, but addition of noise decreased this gap. The authors conducted an independent t test for TDCs and unmedicated children with ADHD in the no-noise condition, t(38) =2.45, p =.019. They found no statistical difference between TDCs and unmedicated children with ADHD during the white noise condition. They also found no statistical difference between TDCs and medicated children, although the TDCs had slightly higher scores during both noise conditions. Children with ADHD and TDCs scored similarly on the verbal 2-back test, with a faster response time for TDCs (noise condition). The authors compared accuracy on the verbal 2-back test for ADHD and TDC groups, F(1, 38) = 0.07, p =.787. They also conducted an independent t test for speed of TDCs and children with ADHD, t(38) = 2.81, p =.0008. TDCs had increased speed during the white noise condition, t(19) = 2.17, p =.043. 6
Comparison of White Noise Versus Medication on Memory Tasks for Children With ADHD White noise was more effective than medication, without regard to specific tasks. The authors found a moderate main effect for noise, F(1, 19) = 16.64, p =.001, ƞ² =.467, using an ANOVA to assess noise condition, medication condition, and task. They found no significant main effect for medication, F(1, 19) = 0.63, p =.436. There was a small interaction effect between noise and medication conditions, F(1, 19) = 4.88, p =.040, ƞ² =.204. On the span-board task, white noise was significant, but medication was not. The authors found no statistically significant difference during the no-noise condition for children on medication or off medication (p =.71), although those on medication scored slightly higher than those off medication. They found statistically significant improvements during the noise condition, as compared with the nonoise condition, for children on medication (p =.034) or off medication (p =.005). On the word recall task, white noise was significant for unmedicated children, whereas medication did not positively affect performance. The authors conducted a paired t test for unmedicated children, with higher scores for noise versus no noise, t(19) = 4.21, p <.0001. Medicated children scored slightly, although insignificantly, higher than unmedicated children in the no-noise condition but scored lower than the unmedicated children (not significantly) in the noise condition. No significant difference was found for the medicated children between noise conditions. Medication had no statistically significant effect on the verbal 2-back task. Was this study adequately powered (large enough to show a difference)? YES Sample size and power were determined on the basis of previous research. NO Were the analysis methods appropriate? YES NO The authors used ANOVAs to compare main effects and interactions for the within- and between-groups factors. They used paired t tests to determine within-subject differences between the noise and no-noise conditions and the medication and no-medication conditions. The authors used independent t tests to determine specific differences between the TDC and ADHD groups. Were statistics appropriately reported (in written or table format)? YES Statistical analyses and graphical representations were used. NO Was participant dropout less than 20% in total sample and balanced between groups? YES NO No participants dropped out. What are the overall study limitations? 7
Convenience sampling introduced bias. The Level II study design is a limitation. The raters were not blinded. Outcomes were not reported as valid or reliable and were not related to in-class or home performance. CONCLUSIONS Application of white noise at 80 db improved word recall (p <.005) and performance on spanboard tasks (p =.005) among individuals with ADHD. White noise influenced performance more than stimulant medication (ps =.001 and.436, respectively). White noise improved performance for those with ADHD but not for TDCs. It is unclear whether the verbal tasks were in Swedish or English, which may limit generalizability. Additionally, children were between the ages of 9 and 15, and age was not specifically assessed during this study. Occupational therapy practitioners should use caution when generalizing the results beyond this age range. Further research is needed to determine conditions that affect performance on the verbal 2-back task for children with ADHD. Future research should be conducted to determine the influence white noise has on performance in more functional tasks, in varied contexts, and with delayed recall. This work is based on the evidence-based literature review completed by Sarah McMillan, MOT, OTR/L, and Faculty Advisor Alison Bell, OTD, OTR/L, Jefferson University. CAP Worksheet adapted from Critical Review Form Quantitative Studies. Copyright 1998 by M. Law, D. Stewart, N. Pollack, L. Letts, J. Bosch, and M. Westmorland, McMaster University. Used with permission. For personal or educational use only. All other uses require permission from AOTA. Contact: www.copyright.com 8