Childhood-onset fluency disorder is the correct answer. It is a neurodevelopmental disorder characterized by disturbances in the normal fluency and time patterning of speech that is inappropriate for the child's age. It can also present with anxiety about speaking. The symptoms of frequent repetitions and other speech dysfluencies presented here characterize this disorder.

The correct answer is "s, z, and th." The presence of speech production difficulties that are outside normal limits and not due to congenital or acquired conditions is pathognomonic for speech sound disorder. Speech sound disorder may occur when children with speech production difficulties have difficulty with phonological knowledge of speech sounds or articulation.

"Broca's area," a small region of the posteriolateral frontal lobe, is responsible for the production of speech. Deficiencies in this area are associated with normal comprehension of words, syntax, and grammar, but an inability to form words for personal expression.

The other choices are incorrect. The "pons" is a part of the brainstem and not involved in language production. The "amygdala" is a part of the limbic system, while the the "corpus callosum" is a wide, flat bundle of neural fibers that connects the left and right hemispheres of the brain.

This individual most likely experienced injury to "Wernicke's area," the part of the brain that is responsible for language comprehension. Damage to this area can result in difficulty understanding speech, and while the ability to produce language may be unaffected, speech is often disordered, non-sensical, or interspersed with inappropriate words or phrases. This is known as Wernicke's aphasia.

The other choices are incorrect. Damage to "Broca's area" would result in impairment with producing words (i.e. getting the words out), with no effect on comprehension. Injury to the "cerebellum" may result in balance or physical coordination issues, while destruction of the "substantia nigra" is typically seen in Parkinson's disease.

Baddeley's Model of Working Memory consists of the following four parts: the central executive, phonological loop, episodic buffer, and visuospatial sketchpad. The semantic buffer does not exist in his model, and is the correct answer. The central executive acts like the "boss" of the other three components and directs our attention. The phonologial loop gives us the ability to temporarily hold spoken or written information in our memory through repetition; for example, you use this when trying to remember a phone number. The visuospatial sketchpad allows us to temporarily remember visuospatial information via mental images. For example, you may use this when navigating through a room to remember there is a chair to your left even when it is out of sight. Last, the episodic buffer is used to relate current experiences to memories of the past. For example, if you see a house and realize it looks similar to your childhood home.

The girl in the question only remembers the last few numbers, which is known as the "recency effect." The recency effect occurs when someone attempts to memorize information and can only recall the last pieces of information that they are attempting to memorize. This likely occurs because the information is still readily available in the phonological loop, and has not yet truly been committed to memory. On the other hand, the "primacy effect" describes the opposite phenomena, when only the first pieces of information are recalled. "Encoding" is the process of transferring information from our senses to memory, and is not descriptive enough to properly answer the question. Finally, "classical conditioning" involves pairing an arbitrary stimulus with a behavior, and has more to do with learned behaviors than memory.

Alzhemier's disease is the most common form of dementia. Nerve cells in the area of the brain associated with memory and cognition are disrupted by plaques and tangles. The disease begins with mild memory loss and progresses to a point where the patient is unable to perform necessary everyday tasks.

Parkinson's disease is associated with abnormal movements, tremors, and a shuffling gait. The symptoms of Parkinson's disease are caused by a lack of the neurotransmitter dopamine, which is caused by a degeneration of neurons.

Multiple sclerosis is a chronic, progressive disorder caused by the body's immune system attacking the myelin sheathes surrounding nerve fibers in the brain, spinal cord, and optic nerves. This damage leads to muscle weakness, numbness, and vision loss.

Amyotrophic lateral sclerosis, or Lou Gehrig disease, occurs when motor neurons progressively deteriorate. This leads to muscle weakness that can progress to paralysis.

A stroke, also called a cerebral vascular accident, occurs when the blood supply to the brain is suddenly interrupted and brain cells are deprived of oxygen. The symptoms of a stroke include sudden onset of weakness, especially on one side of the body, trouble speaking, and vision disturbrances.

The hippocampus is part of the limbic system of the brain—a system that is responsible for many aspects of human functioning, including emotions and memory. The frontal lobe, which controls inhibition and attention, helps regulate executive function. The basal ganglia are situated at the base of the forebrain and are mainly comprised of striatum, the globus pallidus, the substantia nigra, the nucleus accumbens, and the subthalamic nucleus. They are associated with voluntary movement, procedural learning, and emotions, but not associated with episodic memory as the hippocampus is. The occipital lobe of the brain is at the back of the head, and is primarily associated with vision. Last, the cerebral aqueduct is part of the ventricular system in the brain and has nothing to do with higher processing.

The stages of sleep include three non-rapid eye movement (NREM) stages and one rapid eye movement (REM) stage. The stages proceed in the following order and cycle such that N1 follows REM: N1, N2, N3, REM.

During N1, the individual loses sensation of his or her environment and becomes more relaxed, both mentally and physiologically. Brain waves slowly transition from alpha waves (characteristic of wakefulness) to lower frequency theta waves.

During N2, environmental awareness completely disappears. Brain waves are characterized by sleep spindles and K-complexes, which are short bursts of higher frequency waves. General wave patterns follow theta wave trends, with the exception of these interruptions.

During N3, the individual enters deep sleep. Brain activity is characterized by a high presence of very low frequency delta waves. Parasomnias, such as sleepwalking and night terrors, can occur during stage N3 sleep.

REM sleep is characterized by neural acetylcholine secretions, which cause brain waves to increase in frequency and resemble alpha forms. The body's muscles are paralyzed, though the brain's activity is elevated. Dreams occur during this stage, and muscle paralysis is thought to prevent the sleeping individual from attempting to interact with their dreams.

Delta waves are most concretely linked to the N3 stage of sleep.

The non-rapid eye movement stage of sleep, NREM or synchronized sleep, involves four stages. The transition from wakefulness to sleep occurs during stage 1. Eye movements are slow and the electroencepalogram (EEG) shows low brain wave activity. In stage 2, EEG activity is increased. Spikes called K complexes are recorded. In stage 3, eye movement ceases. Wave frequency is reduced and amplitude is increased. Delta activity is recorded on the EEG in stage 4. Stages 3 and 4 are considered deep sleep.