Hearing and music in unilateral spatial neglect neuro-rehabilitation

Abstract

Unilateral spatial neglect (USN) is an attention deficit in the contralesional side of space which occurs after a cerebral stroke, mainly located in the right hemisphere. USN patients are disabled in all daily activities. USN is an important negative prognostic factor of functional recovery and of socio-professional reinsertion. Thus, patient rehabilitation is a major challenge. As this deficit has been described in many sensory modalities (including hearing), many sensory and poly-sensory rehabilitation methods have been proposed to USN patients. They are mainly based on visual, tactile modalities and on motor abilities. However, these methods appear to be quite task-specific and difficult to transfer to functional activities. Very few studies have focused on the hearing modality and even fewer studies have been conducted in music as a way of improving spatial attention. Therefore, more research on such retraining needs is neccessary in order to make reliable conclusions on its efficiency in long-term rehabilitation. Nevertheless, some evidence suggests that music could be a promising tool to enhance spatial attention and to rehabilitate USN patients. In fact, music is a material closely linked to space, involving common anatomical and functional networks. The present paper aims firstly at briefly reviewing the different procedures of sensory retraining proposed in USN, including auditory retraining, and their limits. Secondly, it aims to present the recent scientific evidence that makes music a good candidate for USN patients’ neuro-rehabilitation.

Improving left spatial neglect through music scale playing

“…The exploration of a music keyboard by right‐brain‐damaged patients with left spatial neglect improves when the pressed keys produce the sounds of the music scale, as compared to a silent keyboard or a keyboard producing randomly ordered pitches. Recent investigations have been increasingly considering the potential of sounds and music for ameliorating left spatial neglect (Guilbert et al ., for a review). So far, sounds have been shown to be effective in reducing spatial neglect through two main mechanisms.…”

“…Owing to this commonality, the impaired spatial exploration of patients with neglect could be improved by the ancillary use of non‐spatial feedback, so long as a common magnitude coding is implied. In music therapy settings, sounds are frequently used to support spatial awareness, leveraging on various mechanisms such as the combined spatial–auditory mapping offered by musical instruments, the increase of arousal due to auditory stimulation, and the positive effect on cognitive performance of positive emotions elicited through music (see Guilbert, Clément, & Moroni, for a review). For example, a recent study has provided evidence of improvement in spatial neglect following a 4‐week music therapy intervention: Patients practiced scales and melodies on a custom chime‐bar instrument, in which the spacing between the bars could be progressively enlarged, thus inviting increasingly wide exploration (Bodak, Malhotra, Bernardi, Cocchini, & Stewart, ).…”

Viewing of figurative paintings affects pseudoneglect as measured by line bisection

“…This pattern may depend on art viewing recruiting righthemisphere resources important for visuospatial exploration of the image (Cela-Conde et al, 2009;Di Dio et al, 2016;Lutz et al, 2013), regardless of reward apprehension (at least when images do not evoke strong emotional reactions leading to polarized like/dislike judgements). Our findings may be potentially of interest also from a clinical perspective, for rehabilitation programs of spatial attentional deficits (see Guilbert et al, 2014).…”

Exogenous orienting of attention in hearing: a virtual reality paradigm to assess auditory attention in neglect patients

“…We argue that assessing the auditory modality may lead to a better understanding of patients' behaviours in their ecological environment. A better understanding of attentional mechanisms in hearing could also help to develop rehabilitation strategies (Guilbert et al 2014). Moreover, as USN is frequently associated with a left homonymous hemianopsia (HH), which could prevent from using the visual Posner paradigm, testing attentional orienting in the auditory modality could be an alternative choice for patients with a HH.…”