Beat deafness

Abstract: The condition of congenital amusia, commonly known as tone-deafness, has been described for more than a century, but has received little empirical attention. In the present study, a research effort has been made to document in detail the behavioural manifestations of congenital amusia. A group of 11 adults, fitting stringent criteria of musical disabilities, were examined in a series of tests originally designed to assess the presence and specificity of musical disorders in brain-damaged patients. The results show that congenital amusia is related to severe deficiencies in processing pitch variations. The deficit extends to impairments in music memory and recognition as well as in singing and the ability to tap in time to music. Interestingly, the disorder appears specific to the musical domain. Congenital amusical individuals process and recognize speech, including speech prosody, common environmental sounds and human voices, as well as control subjects. Thus, the present study convincingly demonstrates the existence of congenital amusia as a new class of learning disabilities that affect musical abilities.

Abstract: It is estimated that about 4% of the general population may have amusia (or tone deafness). Congenital amusia is a lifelong disability for processing music despite normal intellectual, memory, and language skills. Here we present evidence that the disorder stems from a deficit in fine-grained pitch perception. Amusic and control adults were presented with monotonic and isochronous sequences of five tones (i.e., constant pitch and intertone interval). They were required to detect when the fourth tone was displaced in pitch or time. All amusic participants were impaired in detecting the pitch changes, and showed no sign of improvement with practice. In contrast, they detected time changes as well as control adults and exhibited similar improvements with practice. Thus, the degraded pitch perception seen in the amusic individuals cannot be ascribed to nonspecific problems with the task or to poor hearing in general. Rather, the data point to the presence of a congenital neural anomaly that selectively impair...

Abstract: Congenital amusia is a neurogenetic disorder that affects the processing of musical pitch in speakers of non-tonal languages like English and French. We assessed whether this musical disorder exists among speakers of Mandarin Chinese who use pitch to alter the meaning of words. Using the Montreal Battery of Evaluation of Amusia, we tested 117 healthy young Mandarin speakers with no self-declared musical problems and 22 individuals who reported musical difficulties and scored two standard deviations below the mean obtained by the Mandarin speakers without amusia. These 22 amusic individuals showed a similar pattern of musical impairment as did amusic speakers of non-tonal languages, by exhibiting a more pronounced deficit in melody than in rhythm processing. Furthermore, nearly half the tested amusics had impairments in the discrimination and identification of Mandarin lexical tones. Six showed marked impairments, displaying what could be called lexical tone agnosia, but had normal tone production. Our results show that speakers of tone languages such as Mandarin may experience musical pitch disorder despite early exposure to speech-relevant pitch contrasts. The observed association between the musical disorder and lexical tone difficulty indicates that the pitch disorder as defining congenital amusia is not specific to music or culture but is rather general in nature.