Interhemispheric callosal transfer in adults with attention-deficit/hyperactivity disorder: an event-related potential study

Abstract

Although subtypes of attention-deficit/hyperactivity disorder have been recognized for some time, few studies have investigated neurophysiological differences that may reflect these. Here, adults with attention-deficit/hyperactivity disorder-inattentive type, attention-deficit/hyperactivity disorder-combined type and controls performed a simple reaction time laterality task (the Poffenberger) during 128-channel electroencephalography recording. Visual-evoked potentials were used to calculate interhemispheric transfer times. As expected for controls, mean right-to-left transfer time was faster than mean left-to-right transfer. No significant asymmetry was, however, found for clinical groups. Compared with controls, attention-deficit/hyperactivity disorder-combined participants demonstrated significantly faster left-to-right transfer, whereas attention-deficit/hyperactivity disorder-inattentive participants had significantly slower right-to-left transfer. These findings support the existence of functional differences between attention-deficit/hyperactivity disorder subtypes, and suggest that the right hemisphere dysfunction theory of attention-deficit/hyperactivity disorder may only be applicable to those without hyperactive symptoms.

Effects of trifluoromethylphenylpiperazine (TFMPP) on interhemispheric communication

“…In addition, there was a significant interaction between the time and treatment (F (1,28) =9.617, p<0.005), indicating that TFMPP reduced the IHTT. In agreement with our previous EEG work in right-handed males Iwabuchi and Kirk 2009;Rolfe et al 2007), these results show shorter IHTT from the right to the left hemisphere compared to left to the right hemisphere in both TFMPP and placebo groups (see Fig. 2a and b).…”

“…This fits with numerous reports of less lateralisation in these groups (Knecht et al 2000;Potter and Graves 1988;Shaywitz et al 1995). In addition, those with a variety of central nervous system (CNS) disorders Burnison et al 1995;Rolfe et al 2007) differ from the general asymmetric IHTT pattern also.…”

“…Poffenberger investigated the interhemispheric transfer time (IHTT), stating that it refers to the time taken for transfer of information from one hemisphere to the other hemisphere via the CC, hence reflecting the speed of human information transfer (Poffenberger 1912). Our previous EEG work ( Iwabuchi and Kirk 2009;Rolfe et al 2007), and that of others (Brown et al 1994;Jeeves and Moes 1996;Nowicka and Fersten 2001;Saron and Davidson 1989), have shown that IHTT from the right to the left hemisphere is shorter than that from left to right. It has been proposed, for example, that this is due to the right hemisphere having a greater number of fast-conducting corticocortical connections than the left hemisphere (Miller 1996).…”

Sex hormonal modulation of interhemispheric transfer time

“…At least this is the case for right-handed males. Left-handers (Iwabuchi & Kirk, 2009), musicians (Patston et al, 2007), those with a variety of neurological disorders Rolfe et al, 2007), and, of particular relevance here, females (Moes et al, 2007;Norwicka & Fersten, 2001) differ from this pattern and show more symmetrical IHTTs. This fits with numerous reports of less FCA in these groups (e.g.…”

“…Previous work employing visual-evoked potentials to measure IHTT, revealed a directional asymmetry in conduction velocities between hemispheres (e.g. Barnett, Corballis, & Kirk, 2005;Brown, Larson, & Jeeves, 1994;Iwabuchi & Kirk, 2009;Moes, Brown, & Minnema, 2007;Nowicka & Fersten, 2001;Patston, Kirk, Rolfe, Corballis, & Tippett, 2007;Rolfe, Kirk, & Waldie, 2007;Saron & Davidson, 1989; see also Marzi, 2010, andTacikowski, 2011, for reviews). The transfer of neural information from the right hemisphere to the left is faster than transfer from the left hemisphere to the right.…”