Aphasia is a language disorder causing difficulty with communication, including speaking, understanding, reading, or writing. While aphasia does not directly cause difficulty swallowing, the two conditions frequently appear together due to shared neurological causes. The medical term for difficulty swallowing is dysphagia, which affects the physical ability to move food or liquid from the mouth to the stomach. When a brain injury, such as a stroke, impacts language regions, it often damages adjacent areas controlling the complex motor functions of swallowing. This close anatomical relationship explains why many individuals with aphasia also experience dysphagia.
Understanding Aphasia
Aphasia is an acquired communication impairment resulting from damage to the parts of the brain that manage language processing, typically located in the left hemisphere. This condition affects an individual’s ability to communicate or comprehend language but does not diminish their underlying intelligence. The most frequent cause of aphasia is a stroke, though other causes include traumatic brain injury, brain tumors, or progressive neurological diseases.
The specific symptoms depend on the location and extent of the brain damage, leading to different classifications. For example, expressive aphasia, often associated with frontal lobe damage, primarily affects the ability to produce speech. In contrast, receptive aphasia, often linked to temporal lobe damage, causes significant difficulty understanding spoken or written language.
Understanding Swallowing Difficulty
Swallowing, or deglutition, is a complex, coordinated physical process involving over 50 pairs of muscles and numerous cranial nerves. Dysphagia is the general term for difficulty moving food or liquids through the mouth, throat, and esophagus. This impairment is a physical or motor function issue, distinct from the cognitive and language deficits seen in aphasia.
Common signs of dysphagia include coughing or choking during or immediately after eating or drinking. Individuals may also experience a sensation that food is stuck in the throat or chest, excessive drooling, or a wet, gurgling voice quality after swallowing. Unmanaged dysphagia carries a serious risk of aspiration, where food or liquid enters the airway, potentially leading to aspiration pneumonia.
Why Aphasia and Swallowing Difficulties Co-Occur
The co-occurrence of aphasia and dysphagia is rooted in the shared neural pathways and proximity of the brain regions that control both functions. Both language and the voluntary phases of swallowing require fine motor control, sensation, and coordination, managed by areas of the cerebral cortex and brainstem. When a major event like a large stroke occurs, the resulting lesion may simultaneously encompass the language centers and the motor control centers for the mouth, tongue, and throat.
Specific areas of the brain are implicated in this overlap, including the insular cortex, the basal ganglia, and the superior temporal gyrus. Damage to these regions, particularly in the left hemisphere, is associated with the simultaneous presence of both communication and swallowing difficulties. It is the single underlying brain injury that produces both conditions, not a cause-and-effect relationship between aphasia and dysphagia.
Managing Swallowing Difficulties
Management of dysphagia is primarily handled by a Speech-Language Pathologist (SLP), who evaluates and treats swallowing disorders. The initial assessment often involves a bedside swallow examination to observe oral motor function and reaction to different food consistencies. If greater detail is needed, the SLP may recommend an instrumental assessment to visualize the swallowing mechanism directly.
Instrumental evaluations include the modified barium swallow study, which is a moving X-ray taken while the person swallows various consistencies mixed with barium. Another method is the fiber-optic endoscopic evaluation of swallowing (FEES), where a small, flexible camera is passed through the nose to view the throat during swallowing. Based on these findings, the SLP develops a plan that includes compensatory strategies and dietary modifications.
Compensatory techniques involve adjustments to body and head positioning, such as tucking the chin, or altering the amount of food taken per bite. Dietary modifications involve changing the texture of foods or the thickness of liquids to make them safer to swallow. Thickened liquids and pureed foods are frequently recommended to slow the transit time of the bolus and reduce the risk of material entering the airway. Swallowing exercises, designed to strengthen the muscles of the mouth and throat, are also incorporated into the rehabilitation plan.