Reflex: What You Need to Know About Your Muscle Stretch and Tendon Reflexes

Reflexes are involuntary movements or actions. Some movements are spontaneous and occur as part of the baby's normal activity. Others are responses to certain actions. Healthcare providers check reflexes to determine if the brain and nervous system are working well. Some reflexes occur only in specific periods of development. The following are some of the normal reflexes seen in newborn babies:

This reflex starts when the corner of the baby's mouth is stroked or touched. The baby will turn his or her head and open his or her mouth to follow and root in the direction of the stroking. This helps the baby find the breast or bottle to start feeding. This reflex lasts about 4 months.

Reflex

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Rooting helps the baby get ready to suck. When the roof of the baby's mouth is touched, the baby will start to suck. This reflex doesn't start until about the 32nd week of pregnancy and is not fully developed until about 36 weeks. Premature babies may have a weak or immature sucking ability because of this. Because babies also have a hand-to-mouth reflex that goes with rooting and sucking, they may suck on their fingers or hands.

When a baby's head is turned to one side, the arm on that side stretches out and the opposite arm bends up at the elbow. This is often called the fencing position. This reflex lasts until the baby is about 5 to 7 months old.

Stroking the palm of a baby's hand causes the baby to close his or her fingers in a grasp. The grasp reflex lasts until the baby is about 5 to 6 months old. A similar reflex in the toes lasts until 9 to 12 months.

Although the rooting reflex disappears typically after 4 to 6 months, its persistence after the expected resolution period may suggest congenital cerebral injury. Multiple reflexive abnormalities may be observed with the rooting reflex, as they are commonly regulated by the frontal lobe. Hyperreflexia responses may suggest neonatal withdrawal after in utero exposure to maternal substance abuse, such as heroin or opiate medications. Recurrence of the reflexes in adults suggests central nervous system pathologies. It may be related to neuronal loss related to normal aging or dementia. Persistence or reappearance of primitive reflexes may serve as an early sign of neurological dysfunction. Further testing should be performed to detect any underlying conditions. Early detection of disease will allow providers to plan out interventions promptly and prevent or slow down the progression of the disease.[6][7][8]

The persistence of the rooting reflex commonly with other primitive reflexes after 4 to 6 months may suggest congenital cerebral palsy. If the rooting reflex persists, the infant may have drooling and a tongue that sits too forward in the mouth. The child will have difficulty swallowing and chewing because of the dysfunctional tongue. Other clinical manifestations include hypotonic or hypertonic muscle tone, asymmetric posture and gait, and delayed developmental milestones. The persistence of primitive reflexes in infancy may also be an early sign of cognitive-developmental delay or autism. Patients with cerebral palsy often develop other conditions, such as learning disability, seizures, and visual or hearing impairment.[9][10][11]

The trigeminal cranial nerve (CN 5), which is responsible for facial sensation, is involved in the rooting reflex. In an infant with an intact CN 5, stroking or touching the corner of his or her mouth will initiate the rooting reflex. If the infant has CN 5 dysfunction, it may result in the absence of the rooting reflex. Congenital trigeminal anesthesia is a rare condition but can significantly impact multiple aspects of neonatal health.[12][13] Corneal epithelial injuries are common clinical manifestations because the afferent limb of the corneal reflex is innervated by the first branch of the CN 5. In contrast, the efferent limb of the reflex is innervated by the facial nerve (CN 7).[14] With the inability to blink appropriately, infants are at higher risk of recurrent corneal epithelial injuries. Loss of facial sensation and decreased lacrimation are also possible clinical manifestations.[15] In a 2002 study to evaluate the development of the corneal reflex in healthy full-term babies, 190 babies were examined in the nursery, and 200 babies were examined in the outpatient clinic. The babies in the nursery ranged between 1 to 3 days of age, and the babies examined in the clinics were ages 1 week to 12 weeks. The study reported that half of the infants developed tactile corneal reflex at 3.5 weeks, and all of the infants developed the corneal reflex at 12 weeks.[16]

Rooting reflexes can be observed in adult patients with frontal lobe pathology. They often present with other primitive reflexes that are normally suppressed by the frontal lobe of the cerebral cortex. Patients with a frontal lobe lesion are also incapable of making decisions, have different personalities, and are not able to control emotions or maintain social interactions. Causes of frontal lobe diseases include head trauma, frontal lobe tumor, multiple sclerosis, and dementia. Frontotemporal dementia most commonly occurs in patients between the ages of 45 and 65.[17] It affects both frontal and temporal lobes of the brain and results in multiple dysfunctions such as apathy, disinhibition, language disability, deficits in executive control.

The rooting reflex is crucial to initiate feeding and promote neonatal growth. Clinicians and nurses should perform thorough neonatal neurological examinations to ensure that all primitive reflexes, including the rooting reflex, are intact. The persistence of the reflex after 4 to 6 months may suggest several conditions, including congenital cerebral palsy and autism. The medical community should educate parents to pay close attention to the child and evaluate whether the reflexes disappear after 4 to 6 months. Parents should be reminded to set up a follow-up appointment after the resolution period. Regular visits may help with the early detection of the disease and the prevention of possible complications. If an infant has congenital trigeminal anesthesia, their clinician should refer the patient to an ophthalmologist to prevent serious corneal disease.

When adult patients present with the recurrence of primitive reflexes, clinicians should order appropriate tests to make a correct diagnosis. Because patients with frontal lobe lesions show impulsive and risky behaviors, family members may show frustration and inability to cope with the patient's disease. Clinicians and nurses should fully explain the situation to the family members about the effects of brain damage and any treatments that may reverse or slow down the progression of the disease. Social services and programs should be employed in these cases to help the patient and the family cope with the progression of the disease and to provide support in the home as much as possible.

Some people do outgrow their seizures, but the decrease in the chance for seizures may not happen for many years: 75% of people with photosensitive reflex epilepsy continue to have seizures after age 25 if not treated.

Clinically, the Bezold-Jarisch reflex is an inhibitory reflex usually denoted as a cardioinhibitory reflex defined as bradycardia, vasodilation, and hypotension resulting from stimulation of cardiac receptors.

The Bezold-Jarisch reflex (BJR) was initially used an eponym for the triad of responses (apnea, bradycardia, and hypotension) following intravenous injection of veratrum alkaloids in experimental animals. The triad depends on intact vagi and is mediated through cranial nervous medullary centers controlling respiration, heart rate, and vasomotor tone.

The Bezold-Jarisch reflex originates from inhibitory mechanoreceptors in the left ventricle (particularly the inferoposterior wall). Stimulation of these inhibitory cardiac receptors by stretch (poorly filled ventricle), chemical substances or drugs increases renin and vasopressin release and parasympathetic activity and inhibits sympathetic activity. These effects promote reflex bradycardia, vasodilation and hypotension (Bezold-Jarisch reflex).

1937-1940 Adolf Jarisch, Jr (1891-1965) and colleagues investigated the effects of viscum album and of veratrine. They confirmed that the depressor effect was reflex in origin. Like von Bezold and Hirt, Jarisch believed that the sensory receptors were in the heart because the effect could be produced after removal of one lung and section of the vagus nerves to the other. They termed the response the Bezold effect

You will notice it in a baby if you move their chin down toward their chest. The knees will bend. If you move the head up toward the back, the legs will straighten. Do not confuse this with the Landau Reflex. They are two separate reflexes.

Back twitching. Back trying to arch up when head is up. Arms bending or body weight shifting back toward their legs when head goes up. If any of these occur the reflex is most likely still present. Exercise needed!

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Your baroreceptor reflex includes neurons and the nerve fibers that carry their messages about your blood pressure. It also includes the cardiovascular system that receives those messages and acts on that information.

The reflex-dom package is a small wrapper around the reflex-dom-core package. It pulls in thecorrect set of dependencies for each target platform (GHCJS, WebKitGTK, WASM, mobile, etc.).Libraries should depend on reflex-dom-core and executables will usually depend on reflex-dom.All of reflex-dom-core's modules are re-exported by reflex-dom. 2ff7e9595c