Hand skill asymmetry in professional musicians

Establishing hand preference: why does it matter?

Hand preference has been associated with psychological and physical well-being, risk of injury, pathological irregularities, longevity, and cognitive function. To determine hand preference, individuals are often asked what hand they use to write with, or what hand is used more frequently in activities of daily living. However, relying only on one source of information may be misleading, given the strong evidence to support a disassociation between self-reported hand preference and outcomes of hand performance assessments. This brief communication is intended to highlight the various methods used to determine hand preference, to discuss the relationship between hand preference inventories and performance measures and to present some recent findings associated with hand preference and musculoskeletal disorders.

Distinct Inter-Joint Coordination during Fast Alternate Keystrokes in Pianists with Superior Skill

Musical performance requires motor skills to coordinate the movements of multiple joints in the hand and arm over a wide range of tempi. However, it is unclear whether the coordination of movement across joints would differ for musicians with different skill levels and how inter-joint coordination would vary in relation to music tempo. The present study addresses these issues by examining the kinematics and muscular activity of the hand and arm movements of professional and amateur pianists who strike two keys alternately with the thumb and little finger at various tempi. The professionals produced a smaller flexion velocity at the thumb and little finger and greater elbow pronation and supination velocity than did the amateurs. The experts also showed smaller extension angles at the metacarpo-phalangeal joint of the index and middle fingers, which were not being used to strike the keys. Furthermore, muscular activity in the extrinsic finger muscles was smaller for the experts than for the amateurs. These findings indicate that pianists with superior skill reduce the finger muscle load during keystrokes by taking advantage of differences in proximal joint motion and hand postural configuration. With an increase in tempo, the experts showed larger and smaller increases in elbow velocity and finger muscle co-activation, respectively, compared to the amateurs, highlighting skill level-dependent differences in movement strategies for tempo adjustment. Finally, when striking as fast as possible, individual differences in the striking tempo among players were explained by their elbow velocities but not by their digit velocities. These findings suggest that pianists who are capable of faster keystrokes benefit more from proximal joint motion than do pianists who are not capable of faster keystrokes. The distinct movement strategy for tempo adjustment in pianists with superior skill would therefore ensure a wider range of musical expression.

Handedness Effects on Playing a Reversed or Normal Keyboard

A group of left-handers, approaching the piano for the first time, showed better performance in playing a reversed keyboard (where the pitch decreased from left to right) than a normal keyboard. By testing a separate group of "experienced" left-handers, it was also found that this observed preference that naive left-handers had for the reversed keyboard can disappear with a few years of practice on a normal keyboard. The initial preference for the reversed keyboard shown by left-handers appeared to be specific for this handedness group, as groups of right-handers, regardless of their level of experience with the piano, performed better with the regular keyboard. Finally, based on these results it was hypothesised that left-handers would encounter considerable frustration in learning the "right-handed" piano. However, an informal demographic study of piano students enrolling at a school of music did not reveal a substantially low prevalence of left-handed pianists.

Intrinsic constraint of asymmetry acting as a control parameter on rapid, rhythmic bimanual coordination: a study of professional drummers and nondrummers

Expert musicians show experience-dependent reduced asymmetry in the structure of motor-related brain areas and in the maximum tapping frequency between the hands. Therefore we hypothesized that a reduced hand-skill asymmetry is strongly related to rapid and rhythmical bimanual coordination and developed a dynamical model including a symmetry-breaking parameter Δω, for human bimanual coordination. We conducted unimanual and bimanual drumming experiments to test the following model predictions. 1) The asymmetry in the maximum tapping frequency is more pronounced in nondrummers than that in drummers. If so, 2) a larger number of phase wanderings (i.e., succession of taps by the same hand), 3) larger SD of the relative phase between the hands (SD ), and 4) larger deviation of mean relative phase (mean ) from 180° would be observed in nondrummers than that in professional drummers during antiphase bimanual drumming at the maximum speed. In a unimanual tapping task, the asymmetry in maximum tapping frequency of nondrummers was more pronounced than that of professional drummers. In a bimanual coordination task, phase wanderings were observed only in nondrummers and SD of the nondrummers is significantly larger than that of professional drummers. On the other hand, there was no significant difference between the mean of the two groups. All these observations were successfully reproduced by changing Δω, which corresponded to the asymmetry in the maximum tapping frequency. These results support the hypothesis indicating that the prominent bimanual coordination pattern emerges spontaneously after a nonspecific change in Δω or symmetry restoration of the nonlinear dynamical systems.

Effect of stick use on rapid unimanual tapping in drummers

Drummers achieve impressive musical performance by using drumsticks. The present study investigated the effect of drumstick use on rapid unimanual tapping performance. 17 drummers tapped a force transducer as fast as possible for 10 sec. with a finger and a drumstick. No significant difference between finger and stick tapping was found for tapping speed and variability of peak force, but there were significant differences in contact time with the tapping surface, mean peak force, and intertap interval variability: Stick tapping had a shorter contact time, a larger peak force, and more stable intertap interval than did finger tapping. Thus, stick use makes it possible to produce a larger impact force and enhances the ability to control timing during rapid manual movement, allowing drummers to play drums powerfully and stably, which is clearly important for the role they have in controlling or enhancing musical rhythm.

New Information about Albert Einstein's Brain

In order to glean information about hominin (or other) brains that no longer exist, details of external neuroanatomy that are reproduced on endocranial casts (endocasts) from fossilized braincases may be described and interpreted. Despite being, of necessity, speculative, such studies can be very informative when conducted in light of the literature on comparative neuroanatomy, paleontology, and functional imaging studies. Albert Einstein's brain no longer exists in an intact state, but there are photographs of it in various views. Applying techniques developed from paleoanthropology, previously unrecognized details of external neuroanatomy are identified on these photographs. This information should be of interest to paleoneurologists, comparative neuroanatomists, historians of science, and cognitive neuroscientists. The new identifications of cortical features should also be archived for future scholars who will have access to additional information from improved functional imaging technology. Meanwhile, to the extent possible, Einstein's cerebral cortex is investigated in light of available data about variation in human sulcal patterns. Although much of his cortical surface was unremarkable, regions in and near Einstein's primary somatosensory and motor cortices were unusual. It is possible that these atypical aspects of Einstein's cerebral cortex were related to the difficulty with which he acquired language, his preference for thinking in sensory impressions including visual images rather than words, and his early training on the violin.

Long-term motor training induced changes in regional cerebral blood flow in both task and resting states

Neuroimaging studies of functional activation often only reflect differentiated involvement of brain regions compared between task performance and control states. Signals common for both states are typically not revealed. Previous motor learning studies have shown that extensive motor skill training can induce profound changes in regional activity in both task and control states. To address the issue of brain activity changes in the resting-state, we explored long-term motor training induced neuronal and physiological changes in normal human subjects using functional magnetic resonance imaging (fMRI) and positron emission tomography (PET). Ten healthy subjects performed a finger movement task daily for four weeks, during which three sessions of fMRI images and two sessions of PET images were acquired. Using a classical data analysis strategy, we found that the brain activation increased first and then returned to the pre-training, replicating previous findings. Interestingly, we also observed that motor skill training induced significant increases in regional cerebral blood flow (rCBF) in both task and resting states as the practice progressed. The apparent decrease in activation may actually result from a greater increase in activity in the resting state, rather than a decrease in the task state. By showing that training can affect the resting state, our findings have profound implications for the interpretation of functional activations in neuroimaging studies. Combining changes in resting state with activation data should greatly enhance our understanding of the mechanisms of motor-skill learning.

Practicing a musical instrument in childhood is associated with enhanced verbal ability and nonverbal reasoning

BACKGROUND

In this study we investigated the association between instrumental music training in childhood and outcomes closely related to music training as well as those more distantly related.

METHODOLOGY/PRINCIPAL FINDINGS

Children who received at least three years (M = 4.6 years) of instrumental music training outperformed their control counterparts on two outcomes closely related to music (auditory discrimination abilities and fine motor skills) and on two outcomes distantly related to music (vocabulary and nonverbal reasoning skills). Duration of training also predicted these outcomes. Contrary to previous research, instrumental music training was not associated with heightened spatial skills, phonemic awareness, or mathematical abilities.

CONCLUSIONS/SIGNIFICANCE

While these results are correlational only, the strong predictive effect of training duration suggests that instrumental music training may enhance auditory discrimination, fine motor skills, vocabulary, and nonverbal reasoning. Alternative explanations for these results are discussed.

Musical training influences linguistic abilities in 8-year-old children: more evidence for brain plasticity

We conducted a longitudinal study with 32 nonmusician children over 9 months to determine 1) whether functional differences between musician and nonmusician children reflect specific predispositions for music or result from musical training and 2) whether musical training improves nonmusical brain functions such as reading and linguistic pitch processing. Event-related brain potentials were recorded while 8-year-old children performed tasks designed to test the hypothesis that musical training improves pitch processing not only in music but also in speech. Following the first testing sessions nonmusician children were pseudorandomly assigned to music or to painting training for 6 months and were tested again after training using the same tests. After musical (but not painting) training, children showed enhanced reading and pitch discrimination abilities in speech. Remarkably, 6 months of musical training thus suffices to significantly improve behavior and to influence the development of neural processes as reflected in specific pattern of brain waves. These results reveal positive transfer from music to speech and highlight the influence of musical training. Finally, they demonstrate brain plasticity in showing that relatively short periods of training have strong consequences on the functional organization of the children's brain.

In search of the loci for sex differences in throwing: the effects of physical size and differential recruitment rates on high levels of dart performance

Contemporary accounts of sex differences in perceptual-motor performance differ in their emphasis on nature and nurture. Study 1 examined the effect of extensive training on one of the largest sex differences, namely accuracy in dart throwing, and found that physical differences in height and reach could not explain sex differences in regional/national level dart players. Study 2 rejected accounts of sex differences based on participation rates by showing that male players recruited from a relatively small pool of club players were superior to the best female players selected from a much larger pool at the international level. Alternative accounts of the source of sex differences in darts, based on male and female players' differential development and practice histories, are discussed.

A high-precision, low cost system for evaluating finger-tapping tasks

Finger-tapping test is extensively employed to assess motor asymmetry in brain damaged patients and also to study the relationship between handedness and performance in normal subjects. The aim of this study was to develop a computer based finger-tapping system that could provide quantitative measures of finger-tapping performance. The system is designed to be used in a standard personnel computer without the need of any other hardware. The software is written in Borland Delphi 6.0 for Microsoft Windows 98 and higher operating systems. Beginning with the Pentium processor, it could be possible to access a time-stamp counter. The time-stamp counter is a 64-bit machine specific register that is incremented by every clock cycle, and keeps an accurate count of every cycle that occurs on the processor. By using a computer with 1 GHz processor speed it is possible to reach a high precision time resolution of 1 mus in finger-tapping tests. Our future prospects for the system are to improve it with various tools such as synchronized recording of electromyography, tapping force monitoring, monitoring of finger angle, and the response to different stimulus parameters by adding appropriate hardware and procedure.

How finger tapping practice enhances efficiency of motor control

Maximum-speed movements have been suggested to put maximum neural control demands on the primary motor cortex; hence, we are asking how primary motor cortex function changes to enable enhanced maximum movement rates induced by long-lasting practice. Cortical function was assessed by recording task-related spectral electroencephalogram alpha-power. Low-resolution brain electromagnetic tomography was used to localize intracortical neuronal sources. The main result is a decrease in neural activity in the left hemisphere (ipsilateral to trained hand) from pretraining to posttraining, whereas right hemispheric activity remained constant across training. This likely reflects the initially limited capacity of the right hemisphere to control demanding left-hand movements, but also highlights its ability to become more efficient with training, indicated by reduced involvement of the left primary motor cortex after training.

Developmental differences in drawing performance of the dominant and non-dominant hand in right-handed boys and girls

This paper addresses the development of fine motor skills in the dominant and non-dominant hand. A total of 60 right-handed children, aged 4-12 years old, were divided in five groups of 12 children, with six girls and six boys in each group. The children were presented with drawing tasks that had to be performed with the dominant and non-dominant hand. Small or large targets had to be connected by lines making either a zigzag (discrete) or slalom (continuous) movement. For each task, effects of age group, gender, hand, and target size were examined for drawing time, percentage of stop time, drawing distance, velocity, and errors. Comparison of stop times in both tasks showed that the zigzag task was performed in a discrete way while the slalom task was performed more continuously, except in the youngest children, who performed both tasks in a discrete manner. With increasing age the children performed the tasks faster, more accurate and with shorter stops. No significant differences were found between boys and girls. While a shorter drawing distance and less errors were observed for the dominant hand in both tasks, drawing time and velocity were not significantly different between both hands. However, the percentage of stop time was higher for the dominant hand. Moving to smaller targets resulted in slower and less accurate performance. A significant interaction of age group and hand was found for errors in both tasks, and for stop time and velocity in the slalom task, suggesting differential maturational changes for both hands in discrete and continuous drawing tasks.

What can studying musicians tell us about motor control of the hand?

Most standard accounts of human anatomy and physiology are designed to meet the requirements of medical education and therefore consider their subject matter from the standpoint of typical rather than outstanding levels of performance. To understand how high levels of skill are developed and maintained, it is necessary to study elite groups such as professional athletes or musicians. This can lead to the rediscovery of arcane knowledge that has fallen into neglect through a lack of appreciation of its significance. For example, although variability in the muscles and tendons of the hand was well known in the nineteenth and early twentieth centuries, it is through recent studies of musicians that its practical significance has become better appreciated. From even a cursory acquaintance with the training methods of sportsmen and women, dancers and musicians, it is clear that sophisticated motor skills are developed only at the cost of a great deal of time and effort. Over a lifetime of performance, musicians arguably spend more time in skill acquisition than almost any other group and offer a number of unique advantages for the study of motor control. Such intensive training not only modifies cortical maps but may even affect the gross morphology of the central nervous system. There is also evidence that in certain individuals this process can become maladaptive. Recent studies of musicians suggest that intensive training can lead to the appearance of ambiguities in the cortical somatosensory representation of the hand that may be associated with the development of focal dystonia; a condition to which musicians are particularly prone. The realization that changes in cortical maps may underlie dystonia has led to the development of new approaches to its treatment, which may ultimately benefit musicians and non-musicians alike.

Converging evidence of ERD/ERS and BOLD responses in motor control research

In this chapter we summarize findings of our group in which we studied the neural underpinnings of finger tapping control using different methods (functional magnetic resonance imaging: fMRI, electroencephalography: EEG, transcranial magnetic stimulation: TMS, and behavioural experiments). First, we found that maximum finger tapping speed is a matter of training as shown for professional musicians. Secondly, we demonstrated that different finger tapping speeds are accompanied by different hemodynamic responses in the primary hand motor area (M1), the cerebellum and partly in pre-motor areas. With increasing tapping speed there is an increase of hemodynamic response in these areas (rate effect). Thirdly, the effect measured with fMRI is substantiated by rate effects measured by means of task-related power decreases in the upper alpha-band (10-12 Hz) over the primary motor cortex. In case of sequential finger movement learning, we observed decreases in task-related alpha-power in lateral PMC (event-related desynchronization: ERD) and simultaneous alpha-power increases in SMA (event-related synchronization: ERS) that came along with training-induced increases in movement rate. This pattern is discussed in relation to the "focal ERD/surround ERS" phenomenon suggested by Pfurtscheller and Lopes da Silva. Finally, we demonstrated that finger tapping speed was slowed by selectively inhibiting the primary hand motor area using TMS. Taken together, these studies demonstrate on the basis of converging evidence that the primary hand motor area is the basic control centre for controlling the movement parameter tapping speed. However, the neural efficiency to control finger tapping speed (as measured with hemodynamic responses or ERD/ERS patterns) is a matter of training.

Lateral preferences in children with intellectual deficiency of idiopathic origin

The goal of this study was to evaluate lateral preferences in a population of children with intellectual deficiency of idiopathic origin, compared with those of typically developing (TD) children. Two groups of children with mild or moderate intellectual deficiency were observed. Handedness (using a 10-item test and Bishop's card-reaching task), eyedness and footedness were studied. The younger group consisted of sixteen 10- to 11-year olds; the older group comprised fourteen 12- to 14-year olds. A control group of fifteen TD children was matched for age with the younger group of intellectually deficient (ID) children. The results show that the occurrence of left-handedness is not higher in children with ID of unknown origin than in age-matched TD children. However, we observed a marginally reduced tendency toward right-handedness in ID than in TD children: more mixed-handers among ID than TD children; test-retest consistency of hand preference significantly lower in the 10- to 11-year-old ID children than in the age-matched TD children; greater tendency of ID children to use their nonpreferred left hand when the card was presented to the left, as compared with TD children. Left-eyedness and crossed hand-eye preference were also more frequent in ID than in age-matched TD children. No age-related difference in laterality was found in ID children. These results partially support other studies indicating that less rightward asymmetry is associated with intellectual deficiency in children.

Gender and Limb Differences in Healthy Elite Dancers: Passé Kinematics

Symmetry of skill development is emphasized in dance training, and many movements are well learned by both genders. The authors conducted a 2-dimensional kinematic analysis of a complex dance movement, the passé, in 12 healthy professional male and female dancers to determine whether there are differences between genders or limbs during the performance of that task. Only peak hip angular displacement differed in men and women. No differences were found between limbs in any of the dependent variables. Dancers displayed consistent temporal and spatial proximal-to-distal sequencing of movement coordination. Despite an indication of limb preference, as defined by gesture or stance limb, there were no differences in proficiency.

Are there pre-existing neural, cognitive, or motoric markers for musical ability?

Adult musician's brains show structural enlargements, but it is not known whether these are inborn or a consequence of long-term training. In addition, music training in childhood has been shown to have positive effects on visual-spatial and verbal outcomes. However, it is not known whether pre-existing advantages in these skills are found in children who choose to study a musical instrument nor is it known whether there are pre-existing associations between music and any of these outcome measures that could help explain the training effects. To answer these questions, we compared 5- to 7-year-olds beginning piano or string lessons (n=39) with 5- to 7-year-olds not beginning instrumental training (n=31). All children received a series of tests (visual-spatial, non-verbal reasoning, verbal, motor, and musical) and underwent magnetic resonance imaging. We found no pre-existing neural, cognitive, motor, or musical differences between groups and no correlations (after correction for multiple analyses) between music perceptual skills and any brain or visual-spatial measures. However, correlations were found between music perceptual skills and both non-verbal reasoning and phonemic awareness. Such pre-existing correlations suggest similarities in auditory and visual pattern recognition as well a sharing of the neural substrates for language and music processing, most likely due to innate abilities or implicit learning during early development. This baseline study lays the groundwork for an ongoing longitudinal study addressing the effects of intensive musical training on brain and cognitive development, and making it possible to look retroactively at the brain and cognitive development of those children who emerge showing exceptional musical talent.

Repetitive motion in perception of tactile sensation in the fingers of string players

Little is known about the mechanisms that underlie the pathophysiology involved in the development of cumulative trauma disorders. Musicians, specifically string players, may be a useful model to examine the cumulative effects of repetitive motion given the highly attended movements of their left hands and the stereotypical grasp of their right hands. Musculoskeletal disorders related to playing are experienced by 39% to 87% of musicians, making musicians a potentially good model for the study of factors involved in development of cumulative trauma disorders. Sensory thresholds for two-point discrimination and light touch were measured in all phalanges of each digit, of each hand. Comparisons were made within and between a control group of 10 nonmusicians who did not engage in repetitive motion and 10 healthy musicians who did. There were 5 violinists, 2 violists, and 3 cellists. The Non-musician group perceived two-points and light touch at significantly lower thresholds in the proximal phalanges of the left hand than the right hand. Significant differences were not present between right and left hands for the means of distal, middle, and proximal phalanges of the Musician group. This lack of significant difference may be due to higher sensory thresholds associated with repetitive use of the left hand of the musicians.

Asymmetry of cortical activation during maximum and convenient tapping speed

An effect of finger tapping rate on the hemodynamic response in primary motor cortex and the cerebellum has been well established over the last years (the rate effect). The present study compares the magnitude of this effect when either the dominant or subdominant hand is used by right and left handers. In contrast to previous studies maximum and convenient tapping rate for both hands are used as tapping tasks. The results confirm "rate effects" for the primary motor cortex and the cerebellum. In addition, a "rate effect" was found for the cingulate motor area. A novel finding is that the cortical and cerebellar "rate effects" are similar for the subdominant and for the dominant hand even though tapping rates are lower for the subdominant hand. This result demonstrates that the subdominant motor cortex and neurally connected cerebellar areas operate at suboptimal control levels although maximum neurophysiological activation has been reached during the maximum tapping task.

Musical Training Enhances Automatic Encoding of Melodic Contour and Interval Structure

In music, melodic information is thought to be encoded in two forms, a contour code (up/down pattern of pitch changes) and an interval code (pitch distances between successive notes). A recent study recording the mismatch negativity (MMN) evoked by pitch contour and interval deviations in simple melodies demonstrated that people with no formal music education process both contour and interval information in the auditory cortex automatically. However, it is still unclear whether musical experience enhances both strategies of melodic encoding. We designed stimuli to examine contour and interval information separately. In the contour condition there were eight different standard melodies (presented on 80% of trials), each consisting of five notes all ascending in pitch, and the corresponding deviant melodies (20%) were altered to descending on their final note. The interval condition used one five-note standard melody transposed to eight keys from trial to trial, and on deviant trials the last note was raised by one whole tone without changing the pitch contour. There was also a control condition, in which a standard tone (990.7 Hz) and a deviant tone (1111.0 Hz) were presented. The magnetic counterpart of the MMN (MMNm) from musicians and nonmusicians was obtained as the difference between the dipole moment in response to the standard and deviant trials recorded by magnetoencephalography. Significantly larger MMNm was present in musicians in both contour and interval conditions than in nonmusicians, whereas MMNm in the control condition was similar for both groups. The interval MMNm was larger than the contour MMNm in musicians. No hemispheric difference was found in either group. The results suggest that musical training enhances the ability to automatically register abstract changes in the relative pitch structure of melodies.

Motoric dominance and sporting excellence: training versus heredity

In the past two decades, laterality in sports has become clearly established. In particular, the concept of motoric dominance in sports has been a fertile area for laterality research. The literature is consistent with the view that in certain sporting skills, sporting competitors with specific motoric-dominance patterns enjoy an advantage over other competitors and are overrepresented in some sports. Two theoretical interpretations have been offered to explain this imbalance of motoric-dominance distribution among sporting individuals: hypotheses of "innate superiority" and "strategic advantage." This paper presents an overview the two hypotheses, along with relevant work so far reported and identifies directions for further empirical research. The theoretical and practical implications of research on laterality in human motor performance are discussed.

A voxel-based approach to gray matter asymmetries

Voxel-based morphometry (VBM) was used to analyze gray matter (GM) asymmetries in a large sample (n = 60) of male and female professional musicians with and without absolute pitch (AP). We chose to examine these particular groups because previous studies using traditional region-of-interest (ROI) analyses have shown differences in hemispheric asymmetry related to AP and gender. Voxel-based methods may have advantages over traditional ROI-based methods since the analysis can be performed across the whole brain with minimal user bias. After determining that the VBM method was sufficiently sensitive for the detection of differences in GM asymmetries between groups, we found that male AP musicians were more leftward lateralized in the anterior region of the planum temporale (PT) than male non-AP musicians. This confirmed the results of previous studies using ROI-based methods that showed an association between PT asymmetry and the AP phenotype. We further observed that male non-AP musicians revealed an increased leftward GM asymmetry in the postcentral gyrus compared to female non-AP musicians, again corroborating results of a previously published study using ROI-based methods. By analyzing hemispheric GM differences across our entire sample, we were able to partially confirm findings of previous studies using traditional morphometric techniques, as well as more recent, voxel-based analyses. In addition, we found some unusually pronounced GM asymmetries in our musician sample not previously detected in subjects unselected for musical training. Since we were able to validate gender- and AP-related brain asymmetries previously described using traditional ROI-based morphometric techniques, the results of our analyses support the use of VBM for examinations of GM asymmetries.

Outstanding language competence and cytoarchitecture in Broca's speech region

Studies on brains of individuals with an exceptional mental capacity are of widespread interest. Here, we analyze the cytoarchitecture of areas 44 and 45 (anatomical correlates of Broca's speech region) of a person with a documented extraordinary competence in language performance (Emil Krebs, E.K.), and compared it with 11 control brains. Morphometry and multivariate statistical analysis revealed significant cytoarchitectonic differences between E.K. and the controls in left and right areas 44, in right 45, and in interhemispheric asymmetries. We conclude, that the exceptional language competence of E.K. may be related to distinct cytoarchitectonic features in Broca's region.

Focal dystonia: advances in brain imaging and understanding of fine motor control in musicians

This article reviews the neuroanatomic and neurophysiologic foundations of music performance and learning. Music performance is regarded as complex voluntary sensorimotor behavior that becomes automated during extensive practice with auditory feedback. It involves all motor, somatosensory, and auditory areas of the brain. Because of the life-long plasticity of neuronal connections, practicing a musical instrument results first in a temporary and later in a stable increase in the amount of nerve tissue devoted to various component tasks. Motor and somatosensory brain regions corresponding to specific subtasks of music performance are larger in musicians starting younger than age 10 years than in the general population. In rare cases, overuse of movement patterns may induce a degradation of motor memory that results in a loss of voluntary control of movements, called musician's cramp. Specific therapeutic options for this condition are reviewed.

Neuromuscular and musculoskeletal problems in instrumental musicians

Over the past 20 years, there has been increasing interest in the medical problems of performing artists. In this review, the major playing-related disorders seen in instrumental musicians are discussed. Among the 1353 instrumentalists personally evaluated, the major diagnoses included musculoskeletal disorders in 64%, peripheral nerve problems in 20%, and focal dystonia in 8%. Of these instrumentalists, 60% were women, although men were the majority in the group with focal dystonia. The average age at the time of evaluation was 37 years for men and 30 years for women. Among musculoskeletal disorders, regional muscle pain syndromes, particularly of the upper limb, upper trunk, and neck, were most common. Specific entities such as tendinitis and ligament sprain were less common. Frequent peripheral nerve disorders included thoracic outlet syndrome, ulnar neuropathy at the elbow, and carpal tunnel syndrome. Each instrument group showed a characteristic distribution of symptoms and signs that appeared to be directly related to the static and dynamic stresses inherent in the playing of the instrument. Electrodiagnostic studies are an important part of the evaluation of these disorders, particularly nerve entrapment syndromes. With carefully designed treatment, the majority of instrumental musicians can return to full and pain-free playing. Nerve entrapment syndromes have the highest treatment success rate, followed by musculoskeletal pain syndromes. Despite some recent innovative approaches, focal dystonia remains largely resistant to therapy.

Voxel-based morphometry reveals increased gray matter density in Broca's area in male symphony orchestra musicians

Broca's area is a major neuroanatomical substrate for spoken language and various musically relevant abilities, including visuospatial and audiospatial localization. Sight reading is a musician-specific visuospatial analysis task, and spatial ability is known to be amenable to training effects. Musicians have been reported to perform significantly better than nonmusicians on spatial ability tests, which is supported by our findings with the Benton judgement of line orientation (JOL) test (P < 0.001). We hypothesised that use-dependent adaptation would lead to increased gray matter density in Broca's area in musicians. Voxel-based morphometry (VBM) and stereological analyses were applied to high-resolution 3D MR images in male orchestral musicians (n = 26) and sex, handedness, and IQ-matched nonmusicians (n = 26). The wide age range (26 to 66 years) of volunteers permitted a secondary analysis of age-related effects. VBM with small volume correction (SVC) revealed a significant (P = 0.002) region of increased gray matter in Broca's area in the left inferior frontal gyrus in musicians. We observed significant age-related volume reductions in cerebral hemispheres, dorsolateral prefrontal cortex subfields bilaterally and gray matter density in the left inferior frontal gyrus in controls but not musicians; a positive correlation between JOL test score and age in musicians but not controls; a positive correlation between years of playing and the volume of gray matter in a significant region identified by VBM in under-50-year-old musicians. We suggest that orchestral musical performance promotes use-dependent retention, and possibly expansion, of gray matter involving Broca's area and that this provides further support for shared neural substrates underpinning expressive output in music and language.

Assessment of fine motor skill in musicians and nonmusicians: differences in timing versus sequence accuracy in a bimanual fingering task

While professional musicians are generally considered to possess better control of finger movements than nonmusicians, relatively few reports have experimentally addressed the nature of this discrepancy in fine motor skills. For example, it is unknown whether musicians perform with greater skill than control subjects in all aspects of different types of fine motor activities. More specifically, it is not known whether musicians perform better than control subjects on a fine motor task that is similar, but not identical, to the playing of their primary instrument. The purpose of this study was to examine the accuracy of finger placement and accuracy of timing in professional musicians and nonmusicians using a simple, rhythmical, bilateral fingering pattern and the technology that allowed separate assessment of these two parameters. Professional musicians (other than pianists) and nonmusicians were given identical, detailed and explicit instructions but not allowed physically to practice the finger pattern. After verbally repeating the correct pattern for the investigator, subjects performed the task on an electric keyboard with both hands simultaneously. Each subject's performance was then converted to a numerical score. While musicians clearly demonstrated better accuracy in timing, no significant difference was found between the groups in their finger placement scores. These findings were not correlated with subjects' age, sex, limb dominance, or primary instrument (for the professional musicians). This study indicates that professional musicians perform better in timing accuracy but not spatial accuracy while executing a simple, novel, bimanual motor sequence.

The musician's brain as a model of neuroplasticity

Studies of experience-driven neuroplasticity at the behavioural, ensemble, cellular and molecular levels have shown that the structure and significance of the eliciting stimulus can determine the neural changes that result. Studying such effects in humans is difficult, but professional musicians represent an ideal model in which to investigate plastic changes in the human brain. There are two advantages to studying plasticity in musicians: the complexity of the eliciting stimulus music and the extent of their exposure to this stimulus. Here, we focus on the functional and anatomical differences that have been detected in musicians by modern neuroimaging methods.

Effects of musical training on speech-induced modulation in corticospinal excitability

We investigated the effect of previous musical training on lateralization of language as indexed by the effects of reading aloud on the modulation of motor evoked potentials (MEPs) induced in the first dorsal interosseus muscles (FDI) by transcranial magnetic stimulation (TMS) of the primary motor cortex. We studied 13 right-handed subjects, seven musicians who had been playing a musical instrument for >10 years and six controls who had never studied a musical instrument. In all subjects, the amplitude of MEPs in the right FDI was facilitated by reading aloud. However, the musicians also showed significant facilitation in the left FDI, while controls did not. These results illustrate striking effects of musical training on lateralization of motor and language functions.

Specialist musical training and the octave illusion: analytical listening and veridical perception by pipe organists

The octave illusion is a useful tool for investigation of the contribution of specialist training to auditory perception. The stimulus that induces the illusion involves two tones with a frequency ratio of 2:1, presented dichotically, and with ear of presentation reversed every 250 ms. Most listeners report hearing a single tone that alternates from high in the right ear to low in the left ear [Scientific American 233 (1975) 92-104]. The first experiment investigated the hypothesis that musical training contributes to veridical perception of an ambiguous stimulus. As hypothesized, participants with the highest level of musical training were more likely to perceive the stimulus veridically. Exploring the effects of specialist training, Experiment 2 contrasted expert pipe organists with other instrumentalists. As hypothesized, participants expert in playing pipe organ--an instrument with harmonic and spatial features similar to those of the octave illusion--were more likely to perceive the stimulus veridically. The results have implications for plasticity of the auditory system and the analytical listening that accompanies specialist, intensive training and rehearsal.

Absolute pitch and planum temporale

An increased leftward asymmetry of the planum temporale (PT) in absolute-pitch (AP) musicians has been previously reported, with speculation that early exposure to music influences the degree of PT asymmetry. To test this hypothesis and to determine whether a larger left PT or a smaller right PT actually accounts for the increased overall PT asymmetry in AP musicians, anatomical magnetic resonance images were taken from a right-handed group of 27 AP musicians, 27 nonmusicians, and 22 non-AP musicians. A significantly greater leftward PT asymmetry and a significantly smaller right absolute PT size for the AP musicians compared to the two control groups was found, while the left PT was only marginally larger in the AP group. The absolute size of the right PT and not the left PT was a better predictor of music group membership, possibly indicating "pruning" of the right PT rather than expansion of the left underlying the increased PT asymmetry in AP musicians. Although early exposure to music may be a prerequisite for acquiring AP, the increased PT asymmetry in AP musicians may be determined in utero, implicating possible genetic influences on PT asymmetry. This may explain why the increased PT asymmetry of AP musicians was not seen in the group of early beginning non-AP musicians.

Comparative lateralisation patterns in the language area of human, chimpanzee, and rhesus monkey brains

Lateralised architectural differences in radial cell column structure were detected in the planum temporale of humans but were not found in homologous regions of ape or monkey brains. This study used a new computer imaging method to quantify the architecture of thousands of cortical minicolumns. A study of Lamina III in the left hemisphere of human brains revealed a wider separation between cell columns and more non-neuronal (empty) space within cell columns compared to the right hemisphere. This asymmetry was absent in the chimpanzee brains and weakly reversed in the rhesus monkey brains. The results imply an evolution towards more clearly defined columnar structures in the left hemisphere of human brains compared to those of monkeys.

Cortical activations in primary and secondary motor areas for complex bimanual movements in professional pianists

Hemodynamic responses were measured applying functional magnetic resonance imaging in two professional piano players and two carefully matched non-musician control subjects during the performance of self-paced bimanual and unimanual tapping tasks. The bimanual tasks were chosen because they resemble typical movements pianists have to generate during piano exercises. The results showed that the primary and secondary motor areas (M1, SMA, pre-SMA, and CMA) were considerably activated to a much lesser degree in professional pianists than in non-musicians. This difference was strongest for the pre-SMA and CMA, where professional pianists showed very little activation. The results suggest that the long lasting extensive hand skill training of the pianists leads to greater efficiency which is reflected in a smaller number of active neurons needed to perform given finger movements. This in turn enlarges the possible control capacity for a wide range of movements because more movements, or more 'degrees of freedom', are controllable.