Executive dysfunction in frontotemporal dementia and corticobasal syndrome

ties and Nicolelis et al. elicited a startle response with stimulation onset and akinesia and locomotion transiently improved. This result is reminiscent of paradoxical kinesis: the sudden ability to overcome akinesia in situations of intense arousal, such as the need to dodge an oncoming truck or escape a burning building.4 Paradoxical kinesis has already been demonstrated in dopamine-depleted rodents that were akinetic in their cages and then swam when placed in a bath of ice.5 However, like the startle reflex, paradoxical kinesis habituates and may not be directly translatable into chronic therapy for PD. Nicolelis et al. also controlled for an arousalrelated phenomenon with control experiments using air puffs and trigeminal stimulation. Unlike startling spinal stimulation, these did not alleviate akinesia, yet this may reflect the differing intensities or modalities. Nevertheless, the letter by Nicolelis et al. is encouraging and we agree that further work is needed in animal models to clarify whether spinal stimulation in some form may be useful as therapy for PD. We are particularly interested in whether continuous stimulation will afford the same results. Wesley Thevathasan, Peter Brown, Oxford, UK