Elsevier

Appetite

Volume 55, Issue 3, December 2010, Pages 679-684
Appetite

Research report
Detrimental effects of gum chewing on vigilance in children with attention deficit hyperactivity disorder

https://doi.org/10.1016/j.appet.2010.10.001Get rights and content

Abstract

Impairments of attention are cardinal features of attention deficit hyperactivity disorder (ADHD) and can seriously affect the daily life of children with ADHD. Despite effective treatment strategies, there is a need of further treatment options that can be added to available and well established treatments. Further treatment options are needed since available treatments are often time consuming, expensive and limited regarding their external validity. Recent research demonstrated that gum chewing has beneficial effects on cognition including certain aspects of attention. Therefore, gum chewing may benefit children with ADHD in situations requiring particular cognitive efforts. In a crossover study, attentional functioning of 32 children with ADHD and 32 children without the condition was examined. All participants were assessed with chewing gum and without chewing gum. A computerized test was used for the assessment of vigilance and sustained attention. The findings of the present study suggest that gum chewing during task execution has detrimental effects on vigilance of both healthy children and children with ADHD. Sustained attention was not affected by gum chewing. Chewing gum, therefore, appears not to improve attentional performance in children with ADHD.

Introduction

Children with attention deficit hyperactivity disorder (ADHD) frequently experience difficulty paying attention in class and often experience social interaction problems, peer rejection, and academic failure or under-achievement (Barkley, 1998, Hoza and Pelham, 1993, Mannuzza et al., 1997). These problems have detrimental effects on the children's development and their inclusion into society. Residual symptoms of ADHD adversely affect the occupational and social life of adolescents and adults with ADHD (Kovner et al., 1998). In view of the far-reaching consequences of ADHD in terms of its disruptive symptoms and its persistence into adulthood, there is a clear need for an effective treatment of patients suffering from the disorder. Treatment of ADHD encompasses various aspects including educational, behavioural, psychological and pharmacological intervention (Anastopoulos et al., 1998, DuPaul et al., 1998, Ramirez et al., 2001, Robin, 1998, Sohlberg and Mateer, 2001, Spencer et al., 1998). The common pharmacological treatment of ADHD is stimulant drug therapy using methylphenidate. This drug, which is considered to be the most effective treatment for ADHD (Hoza and Pelham, 1993, Peeples et al., 1995, Solanto, 1998), has been shown to have beneficial effects on cognition, behaviour and both social and academic skills (DuPaul et al., 1998, Tucha et al., 2006a). Research data clearly indicate that pharmacological treatment is effective alone and appears to be the most effective part of a comprehensive multimodal treatment (Abikoff et al., 2004a, Abikoff et al., 2004b, Greenhill, 1992, Pelham et al., 1992, Wilens and Biederman, 1992). However, drugs used for pharmacological treatment of children with ADHD are associated with some disadvantages. For example, not all children with ADHD respond to pharmacological treatment. Approximately 30% of children and 22–75% of adults with ADHD do not respond satisfactorily to treatment with stimulant medication (Wigal et al., 1999, Wilens et al., 2002). Furthermore, side-effects of medication necessitate the discontinuation of pharmacological therapy in some children. The most common side effects of methylphenidate therapy occur even at low doses and include headache, stomach-ache, insomnia, decreased appetite and dizziness (Ahmann et al., 1993, Shaywitz et al., 1997). Moreover, the effects of stimulants are limited to the period in which the medication is physiologically active and even in drug responders stimulant therapy is not sufficient to bring children with ADHD into a normal range of cognitive, academic and social functioning (Gualtieri and Johnson, 2008, Tucha et al., 2006a). There is also a consensus that a multimodal approach to the management of ADHD is desirable (Cantwell, 1996, Shaywitz et al., 1997) and that non-pharmacological treatment strategies are effective in certain areas such as family functioning or cognition (Anastopoulos et al., 1998, Kerns et al., 1999, Pisterman et al., 1992, Semrud-Clikeman et al., 1999). The main disadvantages of these strategies are that they are often time consuming and expensive and that the generalisation of skills and effects is very often very limited (e.g., Sheridan, Dee, Morgan, McCormick, & Walker, 1996). Therefore, there is a need of additional treatments (1) that can be given in addition to the effective medication (no interactions with pharmacological treatments), (2) that are time and cost effective, (3) that have no detrimental side effects, (4) that can be taken flexibly, for example in situations in which an improved functioning is required, such as exams at school, and (5) that are effective on symptoms that are most detrimental to the patients’ functioning, such as inattention.

In recent years, a small number of studies has examined the effects of gum chewing on cognitive functioning. It has repeatedly been found that chewing a piece of sugar-free chewing gum significantly improves memory and attention functions in healthy children and adults (e.g., Baker et al., 2004, Houcan and Li, 2007, Scholey et al., 2009, Stephens and Tunney, 2004b, Tucha et al., 2004b, Wilkinson et al., 2002). The observed improvement of cognitive functioning has been discussed in terms of a chewing-related increase of regional cerebral blood flow and an enhanced release of insulin (Hirano et al., 2008, Stephens and Tunney, 2004b, Wilkinson et al., 2002). However, there is some controversy regarding the facilitative effect of gum chewing on cognition (Scholey, 2004, Stephens and Tunney, 2004a, Tucha et al., 2004a), because some studies found no effects or even detrimental effects of gum chewing on some aspects of memory and attention (e.g., Johnson and Miles, 2007, Tucha et al., 2004b, Wilkinson et al., 2002).

Since disturbances of vigilance are considered to be the most prominent disturbance of attention in children with ADHD and since a positive effect of gum chewing on cognition has been found in healthy adults (Tucha, Mecklinger, Maier, et al., 2004), it might be expected that chewing gum would improve performance on attention tasks in children with ADHD. In the present study, we will test whether in fact chewing gum improves vigilance and sustained attention in children with ADHD as compared to a control group of children with no attention deficits. To the best of our knowledge, the present study is the first examination in which chewing gum is used in a clinical sample to improve cognitive deficits.

Section snippets

Participants

Thirty-two children with a diagnosed ADHD (Diagnostic and Statistical Manual of Mental Disorders, DSM-IV) participated in the present study (8 girls, 24 boys; mean age = 10.8 years, SEM = 0.4 years). The diagnosis was based on clinical assessment (DSM-IV) including observations, questionnaires and/or interviews with parents and children. Interviews and assessments were performed by experienced clinicians (e.g., child psychiatrists). At the time of the study, all children with ADHD were being

Differences between groups (healthy children versus children with ADHD)

Statistical comparison using the Mann–Whitney U-test revealed that children with ADHD made significantly more commission errors (Z = −2.64, p = .008) and omission errors (Z = −3.27, p = .001) in the no-gum-condition than healthy children. No difference was found between groups in reaction time (Z = −0.91, p = .364). The same pattern of differences between groups was found in the gum-condition (number of commission errors: Z = −2.18, p = .029; number of omission errors: Z = −5.39, p < .001; reaction time: Z = −0.57, p

Discussion

In the present study, attentional functioning of children diagnosed with ADHD and healthy children was assessed. Children with ADHD were on stimulant medication during assessment, since the primary interest of the study was to examine whether gum chewing has an additional beneficial effect on the attention deficit of children with ADHD. Recent studies already demonstrated that cognitive impairments such as attention deficits persist in children with ADHD despite optimal pharmacological

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