Differences and Relations Between Chrono-Biological and

Motor-Functional Characteristics of Infants

Jelena Marunica Karšaj

and Igor Gruić

University Department of Rheumatology, Physical and Rehabilitation Medicine,

University Hospital Centre “Sestre milosrdnice”, Vinogradska cesta 29, 10000, Zagreb, Croatia

Faculty of Kinesiology University of Zagreb, Horvaćanski zavoj 15, 10 000, Zagreb, Croatia

Keywords: Muscle Tone, Neurodevelopment, Jaundice, Infants, Obstetric Mode of Delivery.

Abstract: Differences and relationships between chrono-biological (body weight-BW, body length-BL, gestational age-

GA) and motor-functional characteristics (e.g., muscle tone) of infants with relation to different obstetric

mode of delivery and jaundice were analysed. The assessment of muscle tone is an integral part of neuromotor

evaluation. The study included 179 infants of both genders (AS±SD: age 158,36±110,91 days; BW

3267,78±708,69 grams; and BL of 49,33±3,09 cm) due to muscle tone disorders with the presence of mild

and moderate neurodevelopmental disorders as a sequelae of immature brain impairment. Study revealed

statistically significant differences in chrono-biological variables depending upon the different obstetric mode

of delivery (BW, BL, and GA), as well upon neonatal jaundice (BW, BL, and possibly GA). Also, there is a

statistically significant correlation among chrono-biological variables (BW, BL, GA: 0,62-0,88). When

compared to infant’s age at first physiatrist examination (AFE), individually and combined with GA,

correlations imply importance of further inter-parametrial insights – in this case with relation to muscle tone

classified in 4 groups (normal-, hypo-, hyper-, and changing-). Findings confirm statistically significant

differences between infants differently categorized by muscle tone and infant’s AFE- among hypertonic and

hypotonic infants as well among hypertonic and alternating ones respectively. Although there are no

correlations between the AFE with BW, BL (with GA they are very little correlated – 0,19), there is an

indication that the existing categorization by tone demands more frequent or earlier 'screening' - embedded

into existing communication for a balanced development overall.

1 INTRODUCTION

The assessment of muscle tone is an integral part of

the routine neuromotor evaluation of new-borns,

infants and children. Observation of a fluctuation in

muscle tone aids in setting up a diagnosis, is used as

justification for therapeutic approach, and is

considered as an indicator of neurological change

(Kathrein, 1990). It is well-known that many infants

show one or two signs of atypical neuromotor

performance, and that, generally, only an aggregation

of multiple signs of atypical neuromotor performance

is associated with elevated risk of

neurodevelopmental disorders (Hadders-Algra et al.,

2010). We addressed the alteration of muscle tone in

infants and described the functional characteristics of

muscle tone as follows: lowered (hypotonia),

https://orcid.org/0000-0001-6680-8940

increased (hypertonia), changing muscle tone and

normal mostly of a central etiology which happens to

emerge antenatally, intrapartum, or postnatally.

Muscle tone alterations are often represented in the

so-called “risky children” (children who were

exposed to one or more risk factors for

neurodevelopmental disorders in their medical

history), and those can be an implication of a primary

disorder of the central nervous system (CNS) in terms

of a prior brain disturbances (Lindahl et al., 1988).

The changed muscle tone in terms of hypotonia,

hypertonia and changing muscle tone is considered to

be a symptomatic risk and it stands in need for the

proper and prompt habilitation treatment, even

though the spontaneous normalization is often

achievable (Lazić et al., 2011). Thus, obtaining a

comprehensive medical history is crucial in

Marunica Karšaj, J. and Grui

c, I.

Differences and Relations Between Chrono-Biological and Motor-Functional Characteristics of Infants.

DOI: 10.5220/0012268300003587

In Proceedings of the 11th International Conference on Sport Sciences Research and Technology Support (icSPORTS 2023), pages 237-246

ISBN: 978-989-758-673-6; ISSN: 2184-3201

237

consolidation the extensive list of differential

diagnoses due to muscle tone alternations. Worldwide

shortly after birth, more than 80% of all term and late

preterm infants develop some extent of neonatal

jaundice or hyperbilirubinemia (Keren et al., 2008).

Many studies pointed out that the GA was

significantly associated to jaundice. It has been

described that the risk of jaundice significantly

heightens with lowering GA (Sarici et al., 2004).

Moderate jaundice turned out to be linked with a

significant increase in minor neuromotor disorder

throughout the infancy (Soorani-Lunsing et al.,

2001). Further inspections of muscle tone may be

assessed within sEMG approach (presented in

e.g.(Cifrek et al., 2021).

Bobaths’ methodology gave definition on muscle

tone as “the speed and the degree of resistance to

passive external manipulation of the extremities for a

period of time without interfering with length. It is a

function of the tactile, vestibular and proprioceptive

arrangement enabling an individual to preserve body

posture against the pull of gravity in a resting

position- static as well as the attainment of movement

patterns-dynamic” (Bobath K, 1984). So, tone is

defined as the resistance of muscles to stretch;

therefore, hypotonia is diminished resistance of

muscles to passive stretching (Crawford, 1992).

However, a more appropriate definition of hypotonia

is an impairment of the ability to sustain postural

control and movement against gravity. Thus, floppy

infants exhibit poor control of movement with

prolonged head lag within arm pull test,

procrastinated motor skills, and hypotonic motor

movement patterns. The atypical motor patterns

consist of alterations in postural control, increased

range of motion of joints, and inadequate stability and

movement biomechanics (Peredo et al., 2009). The

critical feature of hypotonia refers to head and neck

control. Mild or benign head lag is a common finding

in new-borns and generally resolves by itself;

however, the presence of severe relentless head lag

beyond three to four months of age typically points to

disorders related to hypotonia and muscle weakness

in infancy (Linder et al., 1998). On the other hand,

hypertonia is defined as an irregularly high resistance

at the time of externally imposed passive movement.

Increased muscle tone is usually characterized by stiff

and inflexible muscles which happen to be hardly

stretched, difficulty in moving from one position to

another, involuntary crossing of lower extremities

when lifted vertically, abrupt tremors or jerks which

aggravate during periods of stress, coordination

deficiency and delay in motor skills maturation. It is

associated with opisthotonus which is assigned to

aberrant axial extension and arching of the trunk

produced by excessive contractions of the paraspinal

musculature (Sanger et al., 2003). Recurrence-wise,

hypertonia is less common in infants than hypotonia

(Sanger et al., 2003).

Final goal of this research is to analyse and

recognize differences between infants differently

categorized by muscle tone and infant’s AFE

(normal-, hypo-, hyper-, and changing-), correlations

among chrono-biological variables, differences in

chrono-biological variables depending upon the

different obstetric mode of delivery and neonatal

jaundice.

2 METHODS

2.1 Sample of Entities

The sample of entities is comprised of 179 infants in

age of 158,36±110,91 days at first physiatrist

examination (as inclusion criterion), with BW

3267,78±708,69 grams and BL of 49,33±3,09 cm,

without special exclusion criterion.

2.2 Sample of Variables

Anthropometric measures and data from antenatal,

intrapartum and postnatal history were obtained on

the first visit either based upon parental report or

collected from documented medical history. Sample

of variables is comprised of 3 independent (grouping)

variables– tone (normal-, hypo-, hyper-, changing),

jaundice (yes/no), birth delivery technique

(spontaneously throughout birth canal/Caesarean

section-CS), and 5 item battery of dependent

variables, 4 basic and one derived – BW (grams), BL

(cm), GA (days), AFE (days), GA and first

examination summed (days).

2.3 Experimental Design

A series of comparisons of (two) independent

variables (groups) were performed. The set of

dependent variables covers chrono-biological

characteristics of entities at birth, with age when first

physiatrist examination was added. The set of

grouping variables was determined by obstetric

modes of delivery, jaundice, and muscle tone. The

study included infants of both genders, aged 0-24

months, who were examined by a physiatrist due to

the muscle tone disorders with the presence of mild

and moderate neurodevelopmental signs and

symptoms as a sequelae of immature brain lesion. The

K-BioS 2023 - Special Session on Kinesiology in Sport and Medicine: from Biomechanics to Sociodynamics

238

modality of habilitation was prescribed

corresponding to infant's clinical indication. Due to

experience follow up shows those infants

predominantly accomplished normal muscle tone and

typical development in further childhood. Our study

is the result of the continuous monitoring of the

development assessed by physical examination of

infants who were at risk due to their antenatal,

intrapartum and postnatal medical history.

Monitoring was carried out methodically, and a

physiatrist examination was conducted in the

outpatient polyclinic of the University Department of

Rheumatology, Physical Medicine, and

Rehabilitation.

While assessing muscle tone, an infant should be

alert and relaxed but not sobbing. Extremity tone is

readily assessed by externally imposed passive

movements. Muscle tone is clinically evaluated by

observation, and palpation during passive

examination of the range of movement of

appendicular and peripheral skeleton. Observation

gives insight into both the global posture of the body

and the acquirement and maintenance of the

antigravity position in the supine and prone position

of an infant. Besides examination is performed

separately in the nuchal, truncal region and on the

upper and lower extremities. In the neck, muscle tone

is evaluated when testing resistance during passive

rotation of the head to the right and left side. The

muscle tone in the shoulder girdle is done by

anteflexion with elevation and adduction of the flexed

arm to the opposite shoulder (“scarf sign”); on the

upper extremities’ pronation and supination, flexion

of the wrist, opening of the hands. Passive examining

of the flexion and lateral flexion of the truncal region

is also involved. Hip flexion, hip abduction and

adduction, knee extension and flexion and foot

dorsiflexion are passively examined on the lower

extremities. Besides the engagement of locomotor

system to assess muscle tone, inevitably are observed

the expression of the infant's face, making eye

contact, social smile and cry, the way of reacting to

auditory, visual stimulus and qualitatively how infant

initiates and performs movement (Goo et al., 2018).

Truncal and nuchal muscle tone may be best

examined using arm traction test, horizontal and

vertical suspension tests. In assessing arm traction

test in supine position no head lag is expected after

the age of three months. On vertical suspension, a

healthy infant should maintain the head perpendicular

and mid-line without descending through the

examiner’s hands. On horizontal suspension, the

infant should maintain a straight back with the head

upright and extremities in flexion position. In

comparison, hypotone infants may wrap over the

examiner’s arms (Leyenaar et al., 2005).

2.4 Data Processing

Descriptive statistics were presented via parameters

of central tendency and dispersion, followed by K-S

tests for distribution normality. Even with existence

of a certain frame for inferential statistics, all analyses

follow nonparametric rules, due to consistency

towards experimental design and results leading to

conclusions based on the nature of analysed and

hypothesized phenomena.

Spearman Rank Correlations among variables and

Mann-Whitney U Test for comparisons of two

independent variables were assessed in TIBCO

Software Inc., ver 14.0.0.15. Power analyses and

sample size calculations were performed via TIBCO

Software Inc., ver 14.0.0.15., and G*Power version

3.1.9.6. Univeresity Kiel, Germany.

2.5 Ethical Issues

Research was approved by Ethical Committee of

University Hospital Centre “Sestre milosrdnice”;

Vinogradska cesta 29, 10000 Zagreb, Croatia, ICH

GCP and Helsinki Declaration; C: 003 06/22-03/003;

No: 251-29-11-22-01-7.

3 RESULTS

Table 1 Descriptive statistics and normality

distribution test (in Appendices).

Table 2 Spearman Rank Order Correlations (in

Appendices).

In addition to basic information about BW and

BL, GA at birth for processing the general health of

infants, obstetric mode (spontaneous, CS), jaundice

(has/none), Apgar score (Casey et al., 2001), which

represents the 10-point score has been used to assess

the condition and prognosis of new-borns worldwide

for the past 70 years, succession of previous

pregnancies and born children, etc. are also

registered.

Table 3 Descriptive statistics analysis according

to obstetric mode of delivery and jaundice (in

Appendices).

The obstetric mode of delivery as a previous

decision of the physician, and manifested neonatal

jaundice as a subsequently established condition,

show different statistical strength for distinguishing

infants by the results of the measured BW and BL,

GA and therefore have impact on decision concerning

Differences and Relations Between Chrono-Biological and Motor-Functional Characteristics of Infants

239

age at which the infant should be included in

habilitation treatment.

Different disorders from normal tone pattern are

shown through results in the observed variables in the

Table 3.

Table 4 Descriptive statistical analysis according

to muscle tone (in Appendices).

According to the average AFE

(Mean±SD:158,36±110,91 for the whole sample,

Mean±SD:151,34±127,59 for normal tone) within

hypertonic infants a deviation is presented

(Mean±SD: 115,67±51,86), which cumulatively with

GA (Mean±SD:387,275±55,3798) presents valid

information to be furtherly analysed.

Table 5 Mann-Whitney U Test by variable

obstetric mode of delivery (in Appendices).

Table 6 Mann-Whitney U Test by variable

jaundice (in Appendices).

Table 8 Mann-Whitney U Test by variable muscle

tone (between groups 1 and 3) (in Appendices).

Box plo t b

Gr ou p

Variable: body weig ht

Median

25%-75%

Min -Ma x

obstetr i c mode of delivery

1000

1500

2000

2500

3000

3500

4000

4500

5000

body wei ght

Bo x plo t b

Group

Variabl e: body leng th

Median

25%-75%

Min -Ma x

obstetri c mode of deli very

body l ength

Box plot b

Group

Variable: g estational age

Median

25%-75%

Min -Max

obstetr i c mode of del ivery

100

120

140

160

180

200

220

240

260

280

300

320

gestational age

Figure 1: Boxplot by Group (obstetric mode of delivery).

Bo x pl ot b

Gr ou p

Variabl e: body weig ht

Median

25%-75%

Min -Ma x

jaundi ce

1000

1500

2000

2500

3000

3500

4000

4500

5000

body weight

Box p lot b

Gr ou p

Variable: body l ength

Median

25%-75%

Mi n- Ma x

jaundice

body l ength

Box p lot b

Gr ou p

Variable: gestational age

Median

25%-75%

Mi n- Ma x

jaundi ce

100

120

140

160

180

200

220

240

260

280

300

320

gestational age

Figure 2: Boxplot by Group (jaundice).

Within series of Mann-Whitney U Tests by

variable tone, among all groups 0-3 (0: hypo-,

1:hyper-, 2:normal-; 3:changing), relevant findings

are presented in table 7 and graph 3 (between groups

0 and 1), and Table 8 and Graph 4 (between groups 1

and 3).

Table 7 Mann-Whitney U Test by variable muscle

tone (between groups 0 and 1) (in Appendices).

4 DISCUSSION AND

CONCLUSIONS

Infants with hypotonia, hypertonia and changing

muscle tone are frequently associated with adjuvant

issues concerning developmental milestones and they

pose challenges for clinicians because they may

appear be the contributing sign of both benign and

serious conditions.

K-BioS 2023 - Special Session on Kinesiology in Sport and Medicine: from Biomechanics to Sociodynamics

240

AFE

B oxplot by Group

Variable: a

e at 1st

siat ric ex aminat ion

Median

25% -75%

Min-Max

muscle tone

-200

200

400

600

800

1000

1200

age at 1st physiatric examination

GA+AFE

B oxpl ot by Group

Variable:

est at ion a

e*a

e at 1st

.exam.

Median

25% -75%

Min-Max

muscle tone

200

400

600

800

1000

1200

1400

1600

gest at ion age*age at 1st phy. exam.

Figure 3: Boxplot by Group (muscle tone).

AFE

B oxplot by Group

Variable: a

e at 1st

siat ric examinat ion

Median

25% -75%

Min-Max

muscle tone

100

150

200

250

300

350

age at 1st physiat ric examination

GA+AFE

B oxplot by G roup

Variable:

est at ion a

e*a

e at 1st

.exam.

Median

25% -75%

Min-Max

muscle tone

250

300

350

400

450

500

550

600

650

gest at ion age*age at 1st phy. exam.

Figure 4: Boxplot by Group (muscle tone).

At first glance, the magnitude of the differential

diagnosis, the oddness of associated disturbances, and

the ongoing advances in diagnostic interpretation and

management may appear overwhelming (Leyenaar et

al., 2005). In prospective observational study infants

born by prelabour CS were compared with a group of

spontaneously born infants. Follow-up assessments

were performed at four and twelve months. Prelabour

CS (n = 66) had significantly lower results in „Ages

and Stages Questionnaire”; adverse

neurodevelopmental outcomes in infants born by

prelabour CS may be apparent already a few months

after birth (Zaigham et al., 2020). Taiwan Birth

Cohort Study was designed to assess the

developmental trajectories of 24 200 infants born in

2005. Their results implied that the association

between CS birth and infant’s neurodevelopmental

disorders was significantly influenced by GA. Infants

born by CS had significant increases in

neurodevelopmental disorders (20% compared with

infants born by spontaneous delivery) (Chen et al.,

2017). In this Swedish population-based birth cohort

study of more 1.1 million infants, births via planned

or intrapartum CS were associated with a moderately

increased risk of neurodevelopmental disorders in

infants, but these associations were attenuated after

adjusting for familial factors (Zhang et al., 2021). In

the representative sample of 4621 singleton infants

the objective of analyses was to determine whether

there are independent effects of BW and GA on motor

and social development (MSD) and the magnitude of

effects. Low BW status and preterm delivery are

associated independently with small, but measurable,

delays in MSD through early childhood and should be

considered along with other known risk factors for

development delays in determining the need for

developmental evaluation (Hediger et al., 2002). In

Irish study within the national sample represented of

73,662, infants born by elective or emergency CS

may face a delay in cognitive and motor development

at age of nine months (Khalaf et al., 2015). In a

systematic review there were 28 studies of small for

gestational (SGA), with a total of 7861 SGA and 91

619 control appropriate for gestational age (AGA)

babies, and three studies of fetal grow restriction

(FGR), with a total of 119 FGR and 49 control AGA

babies. The findings of the study demonstrate that

among infants born at term, being SGA is associated

with lower scores on neurodevelopmental outcomes

compared to AGA controls (Arcangeli et al., 2012).

Developmental changes in the immature central

nervous system have a large impact on the expression

of atypical motor development. It may happen that a

lesion of the developing brain results in neuromotor

dysfunction in infancy but is followed by a typical

developmental outcome. The reverse may also occur

e.g., an apparently typical development in the early

phases of infancy may be followed by the

development of worst neurodevelopmental outcome-

cerebral paralysis (Hadders-Algra, 2004). In infancy,

Differences and Relations Between Chrono-Biological and Motor-Functional Characteristics of Infants

241

atypical motor development may be conveyed by a

delay in the acquiring of developmental milestones

(which may be associated to impaired selection of

neurons), by mild, moderate or severe alteration in

muscle tone (velocity-dependent resistance to

stretch), by a persistence of infantile reflexes (e.g., the

Moro or Galant reflex), and by a reduced variation in

motor repertoire. The following manifestation may be

the most explicit expression of an early lesion of the

brain (Hadders-Algra, 2000), (Prechtl, 2001) whereas

the other signs may be the outcome of a lesion of the

brain but also may be complementary to other types

of adversities during early phase of development,

such as low-risk preterm delivery (Kostović & Judaš,

2007). Results of this study go in line with previous

findings regarding differences in BM (p<0,01), BL

(p<0,02), and GA (p<0,01), for CS vs spontaneously

born infants (Table 5).

Neurodevelopmental maturation may be impacted

by the ability of bilirubin to promote alterations in

synaptogenesis, neuritogenesis, and neurogenesis,

notably in the premature infant. These clinical

manifestations are characterized by the following

domains: neuromotor implications; muscle tone

abnormalities; hyperexcitable neonatal reflexes;

variety of neurobehavior manifestations, expression

and language articulation irregularities; and evolving

cluster of central processing abnormalities, such as

sensorineural, hearing, and visuomotor dysfunctions

(Bhutani & Johnson-Hamerman, 2015). In the study

among two groups of 20 infants’ moderate jaundice

is clearly associated with an increase in minor

neurologic disorder throughout the infancy in terms

of mild irregularities in muscle tone in combination

with indicative postural and reflex dysfunction at the

age of one year (Soorani-Lunsing et al., n.d.). Thirty-

nine term infants with moderate jaundice shortly after

delivery, were assessed and compared to 36 infants

born at term who did not develop neonatal jaundice.

The results of this prospective study demonstrate no

significant differences in neurodevelopmental

outcome parameters with respect to moderate

jaundice between the study groups at age of 3.

(Heimler & Sasidharan, 2010). The Dutch study

which enrolled 43 healthy term infants showed that

up to 18 months of age, term infants with moderate

degrees of hyperbilirubinemia have rates of minor

neurologic dysfunction similar to those of

comparison infants. (Soorani-Lunsing et al., n.d.).

The findings of I Soorani-Lunsing et al., study, which

used sensitive measures for neurodevelopmental

outcome, are in line with the results of three previous

studies among 41324 singleton infants that indicated

that moderate jaundice (bilirubin<342 µmol/l) in

healthy term infants does not affect subsequent

neuromotor outcome (Newman & Klebanoff, 1993).

The subtler symptoms of bilirubin-induced

neurodevelopmental dysfunction (BIND) may be

under-recognized and contribute to increased risk of

motor impairment such as developmental

coordination disorder and learning disabilities

(Johnson & Bhutani, 2011). It has been assumed that

preterm infants may be more predisposed to develop

hearing impairments, whereas on the other hand term

infants may more recurrently develop cerebral palsy

with associated motor disorders and cerebellar

impairment, due to the timing of the bilirubin toxicity

in relation to the developing brain area (Shapiro,

2003). Mild kernicterus may manifest with motor

symptoms including dystonia with or without

athetosis and mild gross motor delays such as late

developmental milestones such as age of initiation of

walking. These infants generally can ambulate well

on their own later in childhood and can speak with

some clarity. Infants exposed to lower TB levels, not

severe enough to cause kernicterus, may have mild

damage to the basal ganglia and cerebellum that may

manifest as mild hypotonia, lack of coordination, or

generalized clumsiness – not severe enough to be

classified as a specific movement disorder (Rose &

Vassar, 2015). However, the influence of exposure to

low-moderate levels of total bilirubin on the

developing CNS is not well understood. Further

analysis is needed to identify the range of motor

impairments that may result from neonatal jaundice,

to perceive the interplay between perinatal risk

factors and bilirubin toxicity, and to develop

enhanced neuroprotective treatment for motor

disorders related to jaundice (Bhutani & Johnson-

Hamerman, 2015). Numerous retrospective studies

have tried to support or refute the relationship of

neonatal jaundice with neurodevelopmental

outcomes. A specific objective in understanding this

correlation has been the use of differing measures of

neurodevelopment. Although neonatal jaundice is

quite common, affecting 60%-80% of new-borns

overall (Chou et al., 2003), observational data have

implicated neonatal jaundice with an elevated risk of

later NDI, though these findings have not always been

reproduced in following studies (Wusthoff & Loe,

2015).

Results of this study also go in line with previous

findings regarding jaundice (Table 6) and differences

in BM (p<0,01), BL (p<0,01), and, with limited

statistical power, in GA (p=0,00).

Within current research, transversal contextual

insights are also necessary to empower understandings

of the main findings. E.g. when analysing the

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242

succession of the child in a family (especially between

second and forth) statistically significant differences

for BW p<0,01, BL p<0,01 and AFE p<0,02 may be

pointed out, as well with regard to succession of

pregnancy (first and second) for BW p<0,001, BL

p<0,001, and with limited statistical power to GA

p<0,022). In line with statistically significant

differences in chrono-biological variables depending

upon the different obstetric modes of delivery (Table

5, Graph 1), as well upon neonatal jaundice (Table 6,

Graph 2) importance of correlations among chrono-

biological variables is also introduced (Table 2) -

statistically significant for BW, BL&GA: 0,62-0,88).

When broadened with and compared to infant’s AFE,

individually and combined with GA (Table 2),

correlation matrix (SB: 0,15-0,95) implies the

importance of further inter-parametrical insights – in

this case with relation to muscle tone classified in 4

groups (normal-, hypo-, hyper-, and changing-).

The most relevant information for the

understanding goal of this research regarding

representative sample is that - infants with diagnosed

increased muscle tone appear to be much earlier

referred from primary care to a physiatrist

(AS±SD:115,68±51,86 days, in Table 4, compared to

average total AS±SD:158,36±110,91 days, in Table

1). The main findings confirm statistically significant

differences between infants differently categorized by

muscle tone and infant’s AFE - among hypertonic and

hypotonic (AFE: p=0,00; GA+ AFE: p<0,01; Table 7;

Graph 3) as well among hypertonic and changing tone

respectively (AFE: p=0,00; GA+ AFE: p<0,01; Table

8; Graph 4).

Conclusively - although there are no correlations

between the AFE of the infant with BW, BL (and with

GA they are very little correlated - 0.19; Table 2),

based on previously presented and discussed findings,

it seems that there is a quantitative and measurable

indication that the existing categorization by muscle

tone indicates the need for more frequent or earlier

short 'screening'. It should be embedded into existing

official protocols and communication by which it is

possible to intervene early enough towards a balanced

overall health of the infant.

The main limitation of the study is not

predominantly within a variability of clinical practices,

but due to different patterns of reference of infants with

diagnosed increased muscle tone - from primary care

to a physiatrist. Also, future studies must be adequately

powered to examine neurodevelopmental impairments

due to immature brain lesion among preterm infants

separately from term infants. The next step within

neurodevelopmental disorders would be stratification

obstetric mode of delivery in terms of spontaneous or

instrumental vaginal delivery, elective or urgent

caesarean section and accompanying severity of

manifested neonatal jaundice.

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APPENDIX

Table 1: Descriptive statistics and normality distribution test.

All (N=179) Mean±SD

Minimu

Maximu

Skewness Kurtosis

Normality

3267,77±708,69 1575,00 4850,00 -0,16 -0,31

K-S d=0,06, p> 0.20;

49,33±3,09 40,00 58,00 -0,38 0,50

K-S d=0,13, p<0,01

268,46±23,05 38,00 294,00 -5,84 55,57

K-S d=0,17, p<0,01

GA+ AFE

426,83±114,58 256,00 1375,00 3,73 26,22

K-S d=0,15, p<0,01

AFE

158,36±110,91 18,00 1095,00 3,94 28,49

K-S d=0,16, p<0,01

Table 2: Spearman Rank Order Correlations.

BL GA AFE GA+AFE

1,00 0,87* 0,67* 0,04 0,19*

0,87* 1,00 0,61* 0,02 0,15*

0,67* 0,61* 1,00 0,18 0,39*

AFE

0,04 0,02 0,18* 1,00 0,95*

GA +AFE

0,19* 0,15* 0,39* 0,95* 1,00

*Marked correlations are significant at p <,05.

Table 3: Descriptive statistics analysis according to obstetric mode of delivery and jaundice.

Mean±SD

0(spontaneous): (n=113) 1(CS): (n=66) 0(no jaundice): (n=92 1(jaundice): (n=87)

BW 3381,48±670,93* 3073,09±734,01* 3409,39±713,59* 3118,02±675,69*

BL 49,75±3,031 48,61±3,07* 49,89±3,29 48,74±2,75

GA 272,03±13,92 262,38±32,57 270,50±28,28 266,32±15,62

GA+ AFE 428,58±124,58 423,83±95,92* 428,39±127,82 425,18±99,42

AFE 156,56±122,32 161,45±88,84 157,89±125,11 158,86±94,33

*Normally distributed results K-S test: d, for p> .20.

Table 4: Descriptive statistical analysis according to muscle tone.

Mean±SD 0:hypo (n=88) 1:hyper (n=40) 2:normal (n=23) 3:changing (n=28)

3248,52±694,44* 3297,70±741,39* 3398,57±831,78* 3178,12±611,63*

49,28±3,22 49,20±3,12 49,96±3,23 49,14±2,52*

266,47±29,09 271,60±14,94 271,00±16,74 268,21±13,81

GA + AFE

442,89±133,53 387,28±55,38* 422,35±135,14* 436,57±80,76*

AFE

176,42±129,90 115,68±51,86* 151,35±127,59* 168,36±75,28*

*Normally distributed results K-S test: d, for p> .20.

Differences and Relations Between Chrono-Biological and Motor-Functional Characteristics of Infants

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Table 5: Mann-Whitney U Test by variable obstetric mode of delivery.

Rank Sum

Group 1

Rank Sum

Group 2

-value

Zad

uste

-value

Valid N

Group 1

Valid N

Group 2

11056,00 5054,00 2843,00 2,64 0,01 2,65 0,01 113 66

10931,50 5178,00 2967,50 2,26 0,02 2,29 0,02 113 66

10987,50 5122,50 2911,50 2,44 0,01 2,48 0,01 113 66

*AFE

9874,50 6235,50 3433,50 -0,88 0,37 -0,88 0,38 113 66

*GA+AFE

10164,50 5945,00 3723,50 -0,01 0,99 -0,014 0,99 113 66

*Interpretations are limited due to results of power/sample size analyses/calculations.

Table 6: Mann-Whitney U Test by variable jaundice.

Rank Sum

Group 1

Rank Sum

Group 2

-value

uste

-value

Valid N

Group 1

Valid N

Group 2

6896,00 9214,00 3068,00 -2,69 0,01 -2,69 0,01 87 92

6854,50 9255,50 3026,50 -2,81 0,01 -2,83 0,01 87 92

6769,50 9340,50 2941,50 -3,06 0,00 -3,10 0,00 87 92

*AFE

7885,00 8225,00 3947,00 0,16 0,88 0,16 0,87 87 92

*GA+AFE 7722,500 8387,50 3894,50 -0,31 0,76 -0,31 0,76 87 92

*Interpretations are limited due to results of power/sample size analyses/calculations.

Table 7: Mann-Whitney U Test by variable muscle tone (between groups 0 and 1).

Rank

Sum Group 1

Rank

Sum Group 2

-value

Zad

uste

-value

Valid N

Group 1

Valid N

Group 2

2*1sided

exact p

AFE

6329,50 1926,50 1106,50 3,36 0,00 3,36 0,00 88 40 0,00

GA+ AFE 6213,00 2043,00 1223,00 2,76 0,01 2,76 0,01 88 40 0,01

Table 8: Mann-Whitney U Test by variable muscle tone (between groups 1 and 3).

Rank

Sum Group 1

Rank

Sum Group 2

-value

uste

-value

Valid N

Group 1

Valid N

Group 2

2*1sided

exact p

AFE

1128,00 1218,00 308,00 -3,130,00 -3,14 0,00 40 28 0,00

GA+AFE 1158,00 1188,00 338,00 -2,760,01 -2,76 0,01 40 28 0,01

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