Infant Movement Types PDF

Lecture 6 Types of movement in infancy cont.  1. Primitive Reflexes Is a relatively stereotyped movement or response elicited by a stimulus, transmitted to CNS to produce it. Dominant movement starting at the last 4 months of prenatal life up to the first 4 months of postna...

Lecture 6 Types of movement in infancy cont.  1. Primitive Reflexes Is a relatively stereotyped movement or response elicited by a stimulus, transmitted to CNS to produce it. Dominant movement starting at the last 4 months of prenatal life up to the first 4 months of postnatal life Controlled sub-cortically  It is an involuntary response to specific stimulation that is often mediated by lower CNS centers newborns exhibit strong reflexes at birth; these reflexes tend to lose their strength over time until they disappear around the fourth month  Primitive reflexes, upon which all other functions stand, are the first neurological functions to develop. Motor development has its beginnings in reflexive movement Failure to appear at the appropriate age, or to persist beyond a certain age, implies some abnormal functioning of the nervous system.  As higher centers of the CNS mature, reflex activity evolves into volitional movement They never totally disappear By four to six months of age, most primitive reflexes modify and no longer evoke a stereotyped response With developmental maturation of higher neural structure, the primitive reflexes become inhibited and postural reactions emerge.  Spinal reflexes 1st level of reflexes according to CNS maturation Primitive reflexes Phasic coordination of movement where muscles do pattern of movement as total flexion or extension Apedal level e.g. flexor withdrawal, extensor thrust, crossed extension  Brainstem reflexes 2nd level of reflexes according to CNS maturation Apedal level Affect distribution of muscle tone due to change of position or head movements e.g. tonic labyrinthine, ATNR, STNR, +ve and –ve supporting reactions, associated reactions  How can we differentiate primitive reflexes from spontaneous movements? 1. Reflexes are responses to specific external stimuli, whereas spontaneous movements do not result from any apparent external stimuli. 2. Reflexive movements are specific and often localized, whereas spontaneous movements tend to be nonspecific and generalized.  Appearance and Disappearance of Reflexes In typically developing infants, infantile reflexes gradually show a less specific response with time; eventually, you can no longer stimulate these reflexes. If the reflexes appear and disappear at an age close to the average, infant is considered having typical development. whereas deviation from the typical pattern and typical execution of the response may signal a problem  A reflex that persists well after the average age of disappearance may indicate a pathological cerebral condition A nonexistent or very weak response on one side of the body compared with the other also could reflect a pathological condition of the lower motor neuron  2. postural reactions postural reactions, or gravity reflexes, help the infant automatically maintain posture in a changing environment Some of these responses keep the head upright, thereby keeping the breathing passages open. Others help the infant roll over Postural reactions generally appear after the infant is 2 months old. These reactions automatically provide for maintaining the body in an upright position through changes of muscle tone  Midbrain reactions Righting reactions (automatic reactions) Quadripedal level Aim to establish a normal head and body relationship Enable a person to assume the normal standing position and maintain stability when changing  Develop in the 1st year of life Enable the child to roll over, set up, creep Some of them is inhibited and others continue throughout life automatic reactions that enable a person to assume the normal standing position and maintain stability when changing positions  Involve complicated mechanisms and processes associated with the structures of the inner ear The activators of righting reactions are the proprioceptors, vestibular system and optic nerve impulses e.g. neck righting acting on body, body righting acting on body, optical righting and labyrinthine righting  Cortical reactions These reactions are mediated by the efficient interaction of cortex, basal ganglia and cerebellum Appears at the with the beginning of bipedal level of maturation It is divided into 2 types: 1. Equilibrium reactions 2. Protective reactions  They response to external disturbance of posture They continue to develop up to age of 5 years Equilibrium reactions: patterns which maintain balance of the whole body in the dynamic relationship between the shifting of one’s center of gravity through space and one’s base of support. Protective reaction: protect the body from the effects of falling down, characterized by extension of the extremities  3. Locomotor Reflexes: Moving in Place The locomotor reflexes appear much earlier than the corresponding voluntary behaviors and typically disappear months before the infant attempts the voluntary locomotor skill. There are three such locomotor reflexes: 1. Stepping 2. Swimming 3. Crawling. THANK YOU