The Complexity of Arnold-Chiari Malformation :: Biology Essays Research Papers

The Complexity of Arnold-Chiari Malformation To the medical doctor, Arnold-Chiari Malformation, which may have a genetic link, is characterized by a small or misshapen posterior fossa (the depression in the back of the skull), a reduction in cerebrospinal fluid pathways and a protrusion of the cerebellar tonsils through the bottom of the skull (foramen magnum) into the spinal canal resulting in a multitude of sensory-motor problems and even some autonomous malfunctions (1). These many symptoms can come in a variety of forms which often makes a clinical diagnosis difficult. To the patient this disorder can present not only physical difficulties but also mental distress. Treatment options and their success rates vary widely, and proponents of the cause are demanding more recognition, research, and success. The study of Arnold-Chiari malformations can lead to additional questions and new understandings about the I-function, sensory-motor input/output paths and the general make-up of the brain and nervous system, but a complete und erstanding of the disorder may be a long time coming. Impairment and sometimes loss of motor control of the body and its extremities is one of the many effects of this disorder. Patients may complain of headaches, neck pain, coughing, sneezing, dizziness, vertigo, disequilibrium, muscle weakness, balance problems, and loss of fine motor control (1). The senses (hearing, sight, smell etc.) may also be affected in deleterious ways. On can have blurred vision, decreased sensation of limbs, unable to locate them without looking, decreased sense of taste, ringing of the ears etc. (2). Two ideas about the nervous system that can be better understood from these observations are the concepts of having and locating the I-function. It seems that the I-function here is very often affected in terms of voluntary movement. A person with Arnold-Chiari malformation who has lost the feeling in and control of his arm for example will not be able to move it even upon someone's request and his or her own desire to do so. Some use of the I-function is definitely impaired. However, these observations do not seem to necessarily imply that some part of the I-function was damaged, because it may very well be located elsewhere- connections may have simply been lost. A person with Arnold-Chiari can still think and have a sense of self, but somehow can not connect with the various body parts that can be affected. Some uses and pathways of the I-function can be understood, but the exact location of it remains vague.