While it has been suggested that music is processed by music-specific neural networks in the brain, this view has been broadened to show that music processing also encompasses generic cognitive functions, such as memory, attention, and executive processes. A study was published in 2009 which investigated the neural and cognitive mechanisms that underlie acquired amusia and contribute to its recovery. The study was performed on 53 stroke patients with a left or right hemisphere middle cerebral artery (MCA) infarction one week, three months, and six months after the stroke occurred. Amusic subjects were identified one week following their stroke, and over the course of the study, amusics and non-amusics were compared in both brain lesion location and their performances on neuropsychological tests.Results showed that there was no significant difference in the distribution of left and right hemisphere lesions between amusic and non-amusic groups, but that the amusic group had a significantly higher number of lesions to the frontal lobe and auditory cortex. Temporal lobe lesions were also observed in patients with amusia. Amusia is a common occurrence following an ischemic MCA stroke, as evidenced by the 60% of patients who were found to be amusic at the one-week post-stroke stage. While significant recovery takes place over time, amusia can persist for long periods of time. Test results suggest that acquired amusia and its recovery in the post-stroke stage are associated with a variety of cognitive functions, particularly attention, executive functioning and working memory. Neuroanatomy
Neurologically intact individuals appear to be born musical.
Juvenile myoclonic epilepsy (JME), also known as Janz syndrome, is a common form of genetic generalized epilepsy (previously known as idiopathic generalized epilepsy), representing 5-10% of all epilepsy cases. This disorder typically first presents between the ages of 12 and 18 with myoclonic seizure manifesting as sudden brief involuntary single or multiple episodes of muscle(s) contractions caused by an abnormal excessive or synchronous neuronal activity in the brain. These events typically occur after awakening from sleep, during the evening or upon sleep deprivation. JME is also characterized by generalized tonic-clonic seizures and a minority also have absence seizures. The genetics of JME are complex and rapidly evolving as over 20 chromosomal loci and multiple genes have been identified thus far. Given the genetic and clinical heterogeneity of JME some authors have suggested that it should be thought of as a spectrum disorder. Epidemiology
The prevalence of JME is approximately 0.1-0.2 per 100,000 and constitutes approximately 5-10% of all epilepsies. Some studies suggest that JME is slightly more common in females than males. The onset of symptoms ranges between the ages of 8 and 36 years and has a peak between the ages of 12 and 18 years. Approximately 15% of children with childhood absence epilepsy and juvenile absence epilepsy subsequently develop JME. In most cases, myoclonic jerks precede the first generalized tonic-clonic seizure by a mean of 3.3 years.