Anomia: Description, Causes and Risk Factors:
An aphasia in which the principal deficit is difficulty in naming persons and objects seen, heard, or felt; due to lesions in various portions of the language area.
Anomia is the hallmark impairment of aphasia and can vary considerably based on aphasia type and severity. Given that nearly all persons with aphasia experience word retrieval difficulty, most comprehensive aphasia treatment approaches utilize some type of naming treatment. Several approaches for treating anomia have been described in the literature. These methods can vary significantly based on the theory that motivates the treatment.
This form of aphasia is caused by damage to either the parietal lobe or the temporal lobe of the brain. The parietal lobe is responsible for integrating sensory information, while the temporal lobe is responsible for processing auditory information, as well as semantics in speech and vision. The damage involves a breakdown in the neural pathways within the brain.
Although the main causes are not specifically known, many researchers have found contributing factors to anomic aphasia. It is known that people with damage to the left hemisphere of the brain are more likely to have anomic aphasia. Broca's area, the speech production center in the brain, was linked to being the source for speech execution problems, and with the use of functional magnetic resonance imaging (fMRI), Broca's area was connected with speech repetition problems, which is commonly used to study anomic patients. Other experts believe that damage to Wernicke's area, which is the speech comprehension area of the brain, is connected to anomia because the patients cannot comprehend the words that they are hearing.
Although many experts have believed that damage to Broca's area or Wernicke's area are the main causes of anomia, current studies have shown that damage in the left parietal lobe is the epicenter of anomic aphasia. One study was conducted using a word repetition test as well as magnetic resonance imaging (MRI) in order to see the highest level of activity as well as where the lesions are in the brain tissue. The researchers saw that damage to neither Broca's area nor Wernicke's area were the sole sources of anomia in the subjects. Therefore, the original model, which showed that damage occurred on the surface of the brain on the grey matter for anomia, was debunked and it was found that the damage was done in the white matter deeper in the brain on the left hemisphere. More specifically, the damage was done to a part of the nerve tract called the arcuate fasciculus, which the mechanism of action is unknown but it is shown to connect the posterior (back) of the brain to the anterior (front) and vice versa.
New data has shown that although the arcuate fasciculus's main function does not include connecting Wernicke's area and Broca's area, damage to the tract does create speech problems because the speech comprehension and speech production areas are connected by this tract. Some studies have found that in right-handed people the language center is 99% in the left hemisphere; therefore, anomic aphasia almost exclusively occurs with damage to the left hemisphere. However, in left-handed people the language center is about 60% in the left hemisphere; thus
, anomic aphasia can occur with damage to the right hemisphere in left-handed people. Therefore, the specific cause of anomia is unknown; however, research is bringing the answer into focus.
Risk Factors may include:
Being at risk for stroke or dementia.
- Having a history of transient ischemic attacks (TIA).
- Being middle to older age (more common in older people).
Patients with nominal aphasia
may use circumlocution, a roundabout way of speaking, to describe things that they cannot remember the word for. They typically recognize objects, and know what they are for or how to use them, even when they cannot recall their name. For example, a nominal aphasic may refer to scissors as "a tool used to cut paper or hair."
Your doctor will ask about your symptoms and medical history. He will do a physical exam and may do a neurological examination, tests to check brain function, and/or order the following:
Exam of muscles used in speech.
- Tests to assess language skills—for example, identifying objects, defining words, and writing.
- CT scan —a type of x-ray that uses a computer to make pictures of structures inside the head.
- MRI scan —a test that uses magnetic waves to make pictures of structures inside the head.
- Electroencephalogram (EEG) —a test that records the brain's activity by measuring electrical currents through the brain (may be done in some situations).
You may be referred to a Neurologist. This is a doctor who specializes in diseases of the Nervous System.
A number of behavioral approaches to rehabilitation of anomia have been described. Some are restitutive in nature and attempt to reactivate lexical-semantic or phonological representations to improve word retrieval. Others are intended to reorganize language functions by engaging alternative cognitive systems to mediate word retrieval or by exploiting residual abilities to circumvent the impairment. A better appreciation of the characteristics of an individual's naming deficit may assist the clinician in selecting appropriate interventions for restitution or substitution of function in the management of this disorder.
Several word retrieval treatment approaches spring from what proponents believe to be the underlying cause of the anomia. Many have dealt with anomia from either cognitive neuropsychological or cognitive neurolinguistic standpoint. Both perspectives, using either single-subject or group designs, have documented successful treatments for persons with anomia. Other treatment approaches have been developed with, perhaps, less emphasis on the underlying naming impairment. These include treatments in the spirit of Shuell's stimulation approach.
Other Treatment Options:
Speech-Language Therapy: The speech therapist will help you to:
Preserve the language skills you have.
- Try to restore those you have lost.
- Discover new ways of communicating.
Therapy may occur one-on-one or in a group. Activities may include:
Using flash cards with pictures and words to help you name objects.
- Repeating words back to the therapist.
- Working with computer programs designed to improve speech, hearing, reading, and writing.
Family Care and Counseling:
You will learn how to apply the lessons learned in speech therapy to your life. Counseling can help you to adjust to returning home. It can also help your family learn ways to better communicate with you.
NOTE: The above information is educational purpose. The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition.
DISCLAIMER: This information should not substitute for seeking responsible, professional medical care.