Neurological diseases are diseases that cause “dysfunction and disharmony in the co-ordination of the body and the nervous system” (Santrock, 2001). The brain is most affected and targeted by these diseases whilst diseases that hinder motor control usually affect the spinal cord. These diseases are not necessarily fatal but are a threat to the well-being and normal functioning of the people who suffer from it (Santrock, 2001). Specific areas of the brain are responsible for certain functions.
Co-ordination of these different areas brings about movement, responses and cognitions. When a particular part of the cerebrum is attacked and damage is caused, functioning related to that particular area of the brain becomes impaired (Santrock, 2001). This essay seeks to explore 4 neurological diseases while focusing on which parts of the nervous system are affected as well as how they are affected, together with the exploration of possible cures for the diseases.
Aids Dementia: The term “dementia” describes a “group of symptoms that are caused by changes in brain function” (http://www.alzheimers.org/generalinfo.htm#whatisdem, 20/03/05). Dementia symptoms may include asking the same questions repeatedly; becoming lost in familiar places; being unable to follow directions; getting disoriented about time, people, and places; and neglecting personal safety, hygiene, and nutrition. (http://www.alzheimers.org/generalinfo.htm#whatisdem, 20/03/05).
Aids dementia is defined as “A degenerative neurological condition attributed to HIV infection, characterized by a group of clinical presentations including loss of coordination, mood swings, loss of inhibitions, and widespread cognitive dysfunctions” (http://aids.about.com/library/glossary/bldef-dementia.htm, 20/03/05). Aids dementia is a repercussion or consequence of the Human Immunodeficiency Virus (HIV), rather than a disease on its own. Aids Dementia is an inevitable reality for patients diagnosed with the HI virus with only a matter of time before symptoms begin to appear. Caused by the HIV virus, Aids dementia directly infects the brain and causes inflammation (encephalitis) in the brain (Gabuzda, D. 20/03/05).
The areas of the brain most affected are the central white and deep grey matter in sub cortical structures such as the Basal Ganglia and Thalamus (forebrain). In severe cases it causes neuron loss in the basal ganglia, occasionally in the cortex (caudate and putamen); it also causes intramyelin swelling and foamy macrophanges (http://www.neuro.wustl.edu/narc/adc.html, 20/03/05). The basal ganglia co-ordinates muscle movement and the thalamus is mostly responsible for receiving and filtering sensory information but also plays a role in memory and control of emotional behaviour (Santrok 2001).
Studies show that 70 – 90% of HIV positive patients suffer from neuropsychological impairment which resulst in symptoms such as slowness, clumsiness, confusion, impaired attention and concentration as well as the inability to perform simple calculations, loss of mental flexibility and poor insight. The patient may also shows signs of apathy, depression, loss of spontaneity and social withdrawal (http://www.aegis.com/topics/oi/oi-adc.html, 20/03/05). Motor defects, which the patient may experience, would be leg weakness, loss of balance and tripping. These symptoms have a very insidious start but progress at a constant rate over the months that follow (http://aids.about.com/library/glossary/bldef-dementia.html, 20/03/05).
The initial trigger that causes the emergence of AIDS dementia in some patients after years of silent brain infection is unknown. One key factor may be the development of certain “neurovirulent HIV strains due to genetic changes in the virus within an individual who has been infected with HIV for many years” (Gabuzda, D, 20/03/05). Cures: There are no cures for this disease although there are preventative measures and treatments that are available. Nevirapine, Kzt or any HIV treatment drug would help in treating and preventing HIV activity in the brain (http://www.aegis.com/topics/oi/oi-adc.html, 20/03/05).
Anxiety Disorders: Anxiety disorders can be explained as an “unpleasant and unjustifiable sense of fear and apprehension” (Santrock 2001). The person suffers severe distress and dysfunction due to the anxiety, which results in an irrational feeling of fear and dread (www.nimh.nih.gov, 20/03/05). The person isn’t necessarily afraid of a particular object or thought; rather it is a constant fear, which becomes a part of a person’s everyday life.
Their anxiety does not necessarily impair their ability to function in the world; however anxiety disorders are usually accompanied by depression (Santrock 2001). Five types of anxiety disorders have been noted. They are obsessive-compulsive disorder (OCD), phobic disorders, post – traumatic stress disorder (PTS), panic disorder as well as general anxiety disorder (GAD) (http://www.nimh.nih.gov/publicat/anxiety.cfm#anx9, 20/03/05).
These disorders are a result of some genetic predisposition, environmental and behavioural factors depending on the disorder. The two parts of the brain that are affected are the Amygdala and Hippocampus of the Limbic system as well as Frontal cortex of the brain (“What are anxiety disorders” http://www.mentalhealth.org/publications/allpubs/ken98-0045/default.asp#, 20/03/05). The Amygdala and Hippocampus of the Limbic system contribute to the control of emotional behaviour and are implicit in memory and learning, and the Frontal Cortex is responsible for motor control (Santrock 2001). The Amygdala stores emotional memories and serves as the “intermediary” between the parts of the brain that process incoming signals and the parts that interpret them (Santrock 2001).
It has the ability to trigger a fear response/anxiety in the case of a ‘threat’ being present. The Hippocampus is also responsible for processing threatening/traumatising stimuli (Santrock 2001). It helps ‘encode’ information into memories in the brain. When a person is exposed to vast amounts of stress, neurons die out and the size of the hippocampus is reduced thus explaining why PTS sufferers have fragmented memory and flashbacks of traumatic events in their lives, which sometimes come back as nightmares (http://www.neuro.wustl.edu/narc/adc.html, 20/03/05).
The obsessive component of OCD relate to the intrusion of “senseless, unwanted, unacceptable, and repetitive thoughts, which are perceived by the thinker as repugnant, blasphemous, and obscene” (http://www.neuro.wustl.edu/narc/adc.html, 20/03/05). The basal ganglia are the structure affected with this disorder. GAD is associated with a chronic sense of dread, fear, and paranoia. Insomnia is a likely symptom. It is an exaggerated sense of tension and worry (http://www.neuro.wustl.edu/narc/adc.html, 20/03/05).
Cures: There are no cures for these diseases but in general, two types of treatment are available for an anxiety disorder-medication and specific types of psychotherapy (http://www.nimh.nih.gov/publicat/anxiety.cfm#anx9, 20/03/05). Medication exists in the form of Anti – depressants, serotonin reuptake inhibitors (SRIs) e.g. Prozac, Venlaflaxine for GAD and anti-anxiety medications. Although medications won’t cure an anxiety disorder, they can keep the symptoms under control and enable you to lead a normal, fulfilling life (http://www.nimh.nih.gov/publicat/anxiety.cfm#anx9, 20/03/05).
Alzheimer’s Disease: Like Aids Dementia, Alzheimer’s disease too is a dementia, except it is of the cortical variety. It affects the older generation and speeds up the deteriorative process of the brain and cognitive functioning (http://www.alzheimers.org/generalinfo.htm#whatisdem, 20/03/05). In Alzheimer’s disease, there is an overall shrinkage of brain tissue. The grooves in the brain (sulci) are noticeably widened and there is shrinkage of the gyri (well-developed folds of the brain’s outer layer). In addition, the ventricles, or chambers within the brain that contain cerebrospinal fluid, are noticeably enlarged (http://www.alzheimersdisease.com/index.jsp, 20/03/05).