GENERAL MOVEMENTS (GMS): WHAT ARE THESE AND WHY THESE MATTER?

Let’s talk about How a Baby Moves!!

Curious?

Well I can say after reading the first sentence many of you must have started imagining and picturising a small baby in front of your eyes. Many questions will pop up in your mind like really should we bother about the actions a baby performs? When should we see a baby moving? What kind of movements is she talking about?

Read on as you will get answers to all such questions in my following blogpost…

Infants with brain lesion move differently compared to infants without brain lesion. An intact brain is a prerequisite for the normal quality of general movements.  General Movements (GMs) or movements in distinct motor patterns can be observed in foetuses as young as 8 weeks postmenstrual age (after first two months of pregnancy). In infants without neurological dysfunction, GMs continue in a similar pattern until about the end of the second month post term (8 weeks old baby), which is then followed by a gradually emerging new GM pattern aka GMs of FIDGETY character. [PRECHTL, 1990] 

These general movements deserve special interest as they are in their altered quality a most reliable indicator of brain (dys)function with a specific prediction of later developing CEREBRAL PALSY (CP).

As discussed in my earlier blog, CP is an umbrella term for conditions that are characterised by a non-progressive, but non unchanging, motor impairment related to brain injury early in development. The age however at which an accurate diagnosis of CP can be made is controversial. The misdiagnoses or false-positive diagnoses of CP are more commonly made before 18 months of age. Commonly reported false positive diagnoses include transient neurological signs of infancy (dystonia), and other neurodevelopmental disorders such as global developmental delay and cognitive impairment.

Differentiating these conditions from CP early on has genetic and treatment implications such as:

  • Surveillance programmes for musculoskeletal and other comorbidities can be instigated and early intervention programmes initiated if CP is diagnosed accurately and early.
  • From the child and family’s perspective, receiving a diagnosis of CP not only provides ‘an answer’ but also streamlines social support. 
  • Diagnosis before school age maximises opportunities for appropriate physical and learning support to be in place for the child’s transition to schooling.

The systematic review (Margot Bosanquet, et al, 2013) which evaluates the accuracy of predictive assessments used to assist in the diagnosis of CP implies, that the assessment with the best evidence and strength for predictive accuracy is the GMA: General Movements Assessment [PRECHTL, 1990], MRI can be used at term corrected age, Neurological examination in the older infant and to a lesser extent, Cranial Ultrasound (CUS) in infants of preterm age.

So now what exactly are Normal and Abnormal GMs?

Normal GMs involve the whole body in a variable sequence of arm, leg, neck and trunk movements. They wax and wane in intensity, force and speed, they have a gradual beginning and end, they are fluent and elegant and create the impression of complexity and variability.

At 6 to 9 weeks post term age (2 months old baby), Fidgety GMs gradually emerge. These are small movements of moderate speed and variable acceleration of neck, trunk and limbs, in all directions, continual in the awake infant, expect during fussing and crying. These are present until 20 weeks (5 months old baby), at which time intentional and antigravity movements start to dominate.

The fidgety general movements are scored as per their occurrence:

(++): Continual FMs, here FMs occur frequently but are interspersed with very short pauses;

(+): Intermittent FMs, FMs occur frequently but with prolonged pauses; and

(+/-): Sporadic FMs, these FMs occur only for 2-3 secs and are interspersed with very long pauses.

Abnormal GMs which can be seen during the prenatal period and during pre term, term and the first two months post term age are:

  • Poor Repertoire of GMs (PR):  The sequence of the successive movement components is monotonous, and the movements of the different body parts do not occur in the complex way as seen in the normal GMs. Infants who display PR will later become DYSKINETIC if characteristic ‘arm movements in circles’ and finger spreading are observed until 5 months post term.
  • Cramped Synchronized GMs (CS): Movements appear rigid and lack the normal smooth and fluent character; all limb and trunk muscles contract and relax almost simultaneously. If this abnormal pattern is observed consistently during several weeks, it is of high predictive value for the development of SPASTIC CP.
  • Chaotic GMs: Movements of all limbs are of large amplitude and occur in a chaotic order without any fluency nor smoothness. they consistently appear to be abrupt. Infants with chaotic GMs develop CS GMs a few weeks later and thus imply a poor prognosis.

Fidgety movements are judged abnormal if they are:

  • Absent (F-): If FMs are never observed from 9-20 weeks post term. This is highly predictive for later neurological impairments; particularly for CP.
  • Abnormal (AF): They look like normal FMs but their amplitude, speed and jerkiness and moderately or greatly exaggerated.

Consistent Cramped-Synchronised General Movements and the absence of Fidgety Movements predict Spastic CP.

The sooner after birth we see CS there are chances of developing severe spasticity (GMFCS level IV or V: CP). The infant which displays later occurrence of CS develops (GMFCS level I, II, III: CP). 

One more question here might bother you…

Is it possible to differentiate between later Spastic Diplegia and Tetraplegia and Hemiplegia?

YES!

Cases with later Diplegia had a later onset and short duration CS GMs along with segmental movements present in upper limbs, than cases with later tetraplegia along with absence of segmental movements in upper as well as lower limbs.

Infants with subsequent hemiplegia had an absence of fidgety movements after b/l CS or PR and asymmetric signs like absence of segmental movements which were reduced on the affected side.

Heinz F. R. Prechtl developed a diagnostic tool for the functional assessment of the young Nervous System; Prechtl’s Assessment of General Movements, which proved to be the most sensitive and specific test currently available to allow early prediction of CP.

Strengths and Benefits:

  • GMA can be performed at bedside or remotely including retrospectively by video recording.
  • GMA takes only 15 minutes of observation when compared with 1 hour of Motor assessment of infancy scoring. 
  • GMA stands out as the most cost effective and sensitive tools available for early prediction of CP.
  • The GMA also helps us to identify preterm infants at the risk for Cognitive Dysfunction, Attention Deficit Hyperactivity Disorder, and Boisterous and Disobedient Behaviour. 
  • Access to training courses is readily available in our country.

In conclusion, I would like to urge all the therapists working in the field of Neuro rehabilitation, Paediatric and NICU setups to empower themselves by learning this tool and thus enable making of a customised early intervention program for our babies.

Babies communicate with us through these movements and we can help them achieve the maximum level of functionality which they deserve.

*Special Thanks to Dr. Christa Einspieler (Prof. of Physiology at the Medical University of GRAZ) for giving me the permission to share this valuable information with you all.

 

REFERENCES:

  1. https://www.ncbi.nlm.nih.gov/pubmed/23574478
  2. http://general-movements-trust.info/.