TONGUE PROTRUSION IN DOWNS.
AN EPIDEMIOLOGICAL SURVEY ON 510 SUBJECTS.
Renato Cocchi, a neurologist and medical
psychologist.
Summary.
In a consecutive
series of 510 Downs, selected by the exclusion of the psychotic subjects, 141
subjects = 27.65%, showed tongue protrusion during the first visit. This group
has 73 M and 66 F, with M/F ratio = 110.60; normal distribution of the
chromosomal diagnoses; average age at the first visit = 46.10 +/- 41.59 months.
When compared with
314 Ss without any tongue protrusion, being both groups divided by age bands of
one year till twenty years, there is a high inverse correlation with the age (p
<0.0009). Nevertheless, a subject of twenty-two years with still tongue
protrusion was found.
The tongue protrusion
in the Downs is an aspecific symptom, without any link with the chromosome 21.
Probably it is a symptom of an internal metabolic stress with irritability of
the hypoglossus nerve nucleus and overstimulation of the genioglossus and
ioglossus muscles, with repetition of the tongue protrusion movement, without
any apparent purpose.
Key words: Syndrome of Down, tongue
protrusion, epidemiology, stress.
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The tongue protrusion is a frequent symptom
in the Down syndrome, but it is not exclusive. Such a symptom can also be
induced by drugs, antipsychotic therapies, but even antidepressant ones,
especially with the use of tricyclic compounds. We find again it in the
scleredema, in the oromandibular dystonias, among which the Meige syndrome. The
tongue protrusion is elicited by the action of the genioglossus and ioglossus
muscles.
Although the tongue protrusion in Downs is a
well-known symptom, I did not find till now (by searching on Google, and on
Medline from 1960, key words used: Down syndrome, tongue protrusion) any
epidemiological investigation on of it.
Since it attracted at once my attention when
I started to follow these persons, I went to verify its presence in the
clinical reports of 510 Down subjects.
Materials and methods
This investigation used the clinical
cards referring to a consecutive, series of home reared and home living Downs as
seen in outpatients' clinic by the present author. Psychotic subjects were
excluded .
During their 1st consultation I reported
the presence of tongue protrusion the related card.
From all the records I discarded those
pertaining to autistic or PDD Down Ss because I saw that this second heavier
pathology can modify every sympotm or behaviour.
From the remaining records I collected:
- gender;
- chromosomal diagnosis;-
- age at 1st consultation;
- positive or negative presence of the
symptom "tongue protrusion" .
I processed data by gender, chromosomal
anomalies, age bands and I applied Chi Square Test, when suitable, or the test
of correlation.
Results
I reported the data pertaining to the
subjects of the clinical records in the following tables.
Tab. 1: Epidemiological data of the whole cohort.
|
Nr. of Ss |
510 |
100.00% |
|
Malesi |
292 |
57.25% |
|
Females |
218 |
42.57% |
|
M/F ratio |
133.94/100 |
|
|
|
|
|
|
Chromosomal diagnoses |
|
|
|
Standard trisomy 21 |
461 |
90.39% |
|
Mosaicisms |
16 |
3.14% |
|
Translocations |
16 |
3.14% |
|
Unknown, only clinical diagn. |
17 |
3.33% |
|
|
|
|
|
Age at 1st consultation (months) |
|
|
|
Range |
6-510 |
|
|
Mean +/- SD |
71.37 +/- 69.71 |
|
As we can see in the Table 1, the M/F
ratio overlaps the same known ratio of Italian live-born Down babies. Even the
distribution of chromosomal anomalies fitted the variance range for Italian and
International samples.
For these reasons we ought to maintain
the present sample as representative at least of the Italian Downs population.
Tab. 2. Distribution of the prevalence of
the symptom "tongue protrusion".
|
. |
No. of Ss |
% |
|
The whole sample |
510 |
100.00 |
|
|
||
|
Not investigated (?) |
55 |
10.78 |
|
Evident tongue protrusion (+) |
136 |
26.86 |
|
Rare tongue protrusion (+/-) |
5 |
0.78 |
|
No tongue protrusion (-) |
314 |
61.57 |
The tongue protrusion accounts for 27.64% of
subjects. It is much unlikely that the not investigated persons (10.78%) belonged
to the group with the evident symptom.
Tab. 3: Epidemiological data of the
subsample of subjects with tongue protrusion.
|
|
No. of Ss |
% |
|
Symptom present |
141 |
100.00 |
|
Males |
74 |
52.48 |
|
Females |
67 |
47.52 |
|
M/F ratio |
110.45 |
|
|
|
||
|
Chromosomal diagnosis |
|
|
|
Standard trisomy 21 |
130 |
92.21 |
|
Translocations |
5 |
3.54 |
|
Mosaicisms |
5 |
3.54 |
|
Only clinical diagnosis |
1 |
0.71 |
|
|
||
|
Age at first consultation. |
|
|
|
Average +/- SD (months) |
46.10 +/- 41.59 |
|
|
Range (months) |
6-266 |
|
The usual male prevalence is maintained,
even if clearly lesser than Camera and Mastroiacovo, 1984, found at birth for
Italian children. The distribution of the chromosomal anomalies is not far from
what reported for Italian and international Down populations.
Here, the average age at the first
consultations is much lower than that of the whole sample, and the age range is
narrower.
It is to notice that even one subject of
more of twenty-two years (266 months) showed tongue protrusion.
Tab. 4. Epidemiological data of the subgroup
of subjects without tongue protrusion.
|
. |
No. of Ss |
% |
|
Without tongue protrusion |
314 |
100.00 |
|
Males |
192 |
61.15 |
|
Females |
122 |
38.85 |
|
M/F ratio |
157.38 |
|
|
|
||
|
Chromosomal diagnosis |
|
|
|
Standard trisomy 21 |
282 |
89.81 |
|
Translocations |
9 |
2.87 |
|
Mosaicisms |
8 |
2.55 |
|
Only clinical diagnosis |
15 |
4.78 |
|
|
||
|
Age at first consultation. |
|
|
|
Average +/- SD (months) |
84.82 +/- 78.72 |
|
|
Range (months) |
6-510 |
|
The table 4 shows certainly interesting
data. The male prevalence is larger than the usual prevalence and than that of the
total sample. If we split the fifteen cases with only clinical diagnosis by
rates, the distribution of the chromosomal anomalies parallels what known for
Italians and international populations. The average age at first consultations
is nearly the double of that of the subjects with tongue protrusion, and it is
the same as for the Standard Deviation. Here, the age range has its maximum
limit that approaches the double of the maximum limit found in subjects with
tongue protrusion.
Tab. 5: Epidemiological data of the subgroup
of Ss not investigated as for the tongue protrusion.
|
|
No. of Ss |
% |
|
Sympt. not investigated |
55 |
100.00 |
|
Males |
31 |
56.36 |
|
Females |
24 |
43.94 |
|
M/F ratio |
129.17 |
|
|
|
||
|
Chromosomal diagnosis |
|
|
|
Standard trisomy 21 |
48 |
87.28 |
|
Translocations |
3 |
5.45 |
|
Mosaicisms |
3 |
5.45 |
|
Only clinical diagnosis |
1 |
1.82 |
|
|
||
|
Age at first consultation |
|
|
|
Average +/- SD (months) |
68.78 +/- 60.98 |
|
|
Range (months) |
6 - 310 |
|
The not investigated subgroup has a reduced
M/F ratio, nearer to the normalcy and to the whole series of 510 cases. It has
also a distribution of the chromosomal anomalies that is put out from the
normal distribution for a modest deficit of the standard trisomies 21, and a
modest excess of mosaicisms and of translocations. The average age at first
visits approaches that of the subgroup without tongue protrusion. The age
maximum limit is intermediary between that of the subjects with tongue
protrusion and that of the subjects without it.
Tab.6: Comparison among rates for age bands,
between the subgroup with tongue protrusion and that surely without it.
|
Age bands (months) |
With tongue protrusion |
% |
Without tongue protrusion |
% |
|
1-12 |
24 |
17.02 |
29 |
9.24 |
|
13-24 |
29 |
20.56 |
43 |
13.68 |
|
25-36 |
22 |
15.60 |
42 |
13.38 |
|
37-48 |
18 |
12.77 |
15 |
4.78 |
|
49-60 |
12 |
8.51 |
27 |
8.60 |
|
61-72 |
5 |
3.55 |
19 |
6.05 |
|
73-84 |
11 |
7.80 |
10 |
3.18 |
|
85-96 |
3 |
2.13 |
14 |
4.46 |
|
97-108 |
3 |
2.13 |
11 |
3.50 |
|
109-120 |
8 |
5.67 |
22 |
7.01 |
|
121-132 |
2 |
1.42 |
12 |
3.82 |
|
133-144 |
2 |
1.42 |
16 |
5.10 |
|
145-156 |
0 |
0.00 |
10 |
3.18 |
|
157-168 |
0 |
0.00 |
7 |
2.23 |
|
169-180 |
0 |
0.00 |
8 |
2.55 |
|
181-192 |
1 |
0.71 |
9 |
2.87 |
|
193-204 |
0 |
0.00 |
3 |
0.95 |
|
205-216 |
0 |
0.00 |
0 |
0.00 |
|
217-228 |
0 |
0.00 |
1 |
0.32 |
|
229-240 |
0 |
0.00 |
2 |
0.64 |
|
241+ |
1 |
0.71 |
14 |
4.46 |
|
Totals |
141 |
100.00 |
314 |
100.00 |
Chi Square (with 0 = 0.01
by need of calculation) = 1387.199 with 20 df and p < 0.0001.
The test suggests a very high probability
that the two subgroups belong to two different populations, but it is possible
that the tongue protrusion has some relationship with the age. The presence of
the symptom in a person whose age was higher than twenty years does not deny
such a possibility.
Graph 1
Correlation: r
= -0.856; t = -7.025, with 18 df and p < 0.0009.
There is a statistically significant highly reverse
correlation with the age. The tongue protrusion strongly inclines to disappear
with the age.
Discussion.
I repeat here that, as for what I could verify,
this is the first epidemiological survey on the prevalence of the tongue
protrusion in a cohort of 510 Down subjects, already personally seen.
The first result, already reported by other
researchers, is that the tongue protrusion is not a common symptom in Down
persons, on the contrary I could find it only fewer more than a quarter of them
(27.65%).
From that it comes out that this symptom
cannot directly depend on the trisomy 21, otherwise all Downs should have it.
As I said in the introduction, it is not an
exclusive symptom of the Down syndrome. On the contrary it may be a side-effect
of therapies with neuroleptic or tricyclic antidepressant drugs, beyond its
presence in the oromandibular dystonias.
For what concerns the subsample of Ss with
tongue protrusion, here I found a lowering of the usual male prevalence, which
however it is kept as such.
The average age at first consultation is
much lower than that of the whole sample, and the age range is narrower.
In the subsample of Ss without tongue protrusion
the male prevalence becomes larger than that of the whole sample, and the
average age at the first consultation is much higher, and the age range widens.
The comparison between these two subsamples
pointed out a very high statistic probability that they belong to two different
populations. In other words the Down persons with tongue protrusion, at least
until this symptom is present, are not equal to
those without tongue protrusion, even if their two chromosomal diagnoses
distributions are closely overlapping.
The analysis of the time course of the
symptom, as evident till twenty years in the graph 1, has shown an inverse
correlation with the age, statistically very significant. The symptom inclines
to disappear as the child grows. Here, the presence of a subject with more than
twenty-two years and still having tongue protrusion points out that, although
very close, this inverse correlation is not however absolute. At least it is
not so till the age of this subject.
On the origin of this symptom we can only do
hypotheses. Since it comes out by the action of the genioglossus and ioglossus
muscles, the more probable hypothesis is that both receive unintentional
stimulations from the hypoglossus nerve, the XII bilateral cranial nerve, with
exclusive motor function. It originates with a series of roots that escape from
the bulb, between the pyramid and the inferior olivary complex (Adams and
Victor, 1989).
The tongue protrusion is one of the first
gestures learned from the child of 3-4 weeks of life, by imitation (Abravanel
and Sigafoos, 1984 ). This proves that we are dealing with a perfectly
developed and already functional neuromotory structure. It seems to be excluded
that the unintentional tongue protrusion is something that follows monolaterali
troubles of the neuronal pathway, or of one or both genioglossus and ioglossus
muscles. Similar events exist, and the result is a monolaterale paresis with
asymmetry of the tongue protrusion, and consequent lingual atrophy.
The appearance of tongue protrusion during
therapies with neuroleptic or antidepressant drugs directs or to a toxicity
phenomenon or to overstimulation, not excluding both together. In Down children
it is more probable that we are dealing with overstimulation of the hypoglossus
nerve nucleus, with unintentional repetition of the tongue protrusion.
For my experiences on the squint in these
children ( Cocchi, 1991) this not seems to me an air-built hypothesis.
Conclusions.
In a consecutive series of 510 Down,
selected with the exclusion of the psychotic subjects, 141 subjects = 27.65 %,
showed tongue protrusion during the first consultation.
The symptom has a very high inverse
correlation with the age. Nevertheless, I found a twenty-two-years person
presenting it.
The tongue protrusion in Downs is an
aspecific symptom, without any link with the chromosome 21. Probably is a
symptom of internal metabolic stress with irritability of the hypoglossus nerve
nucleus and overstimulation of the genioglossus and ioglossus muscles, with
repetition of the tongue protrusion movement, without any apparent purpose.
References.
Abravanel E, Sigafoos
AD. Exploring the presence of imitation during early infancy. Child Dev. 1984,
55: 381-392.
Adams
RG, Victor M. Principles of Neurology. McGraw-Hill, New York, 1989.
Camera G., Mastroiacovo
P.: Epidemiologia della sindrome di Down. In. Ce.Pi.M. (ed): Aspetti
epidemiologici, genetici, clinici, riabilitativi e sociali della sindrome di
Down. Ce.Pi.M., Genova 1984: 225-230.
Cocchi R.: Drug therapy of squint in Down syndrome subjects. Results according to the length of drug taking: Report on 125 cases. Ital. J. Intellect. Impair. 1991, 4: 9-14. <www.stress-cocchi.net/Symptoms2.htm>.
Cocchi R. Forme a mosaico
nella sindrome di Down: indagine su 16 casi. Riv. It. Disturbo Intellet. 1996,
9: 107-116. <www.stress-cocchi.net/Down23.htm>.
Posted on Internet on April 2004. Copyright by Renato Cocchi,
2004.
Author's address: Renato Cocchi, via Rabbeno, 3
42100 Reggio Emilia (Italy)
renatococchi@libero.it
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