Impaired comprehension of metaphorical expressions in very mild Alzheimer’s disease

Figures & data

Table 1 Demographic and neuropsychological data of the participating groups

	Normal controls	Very mild AD	Mild AD	P-value
Age (years)	73.6±4.7	72.3±4.0	74.5±3.9	nsa
Sex (male/female)	9/11	9/11	6/14	nsb
SLTA: Auditory word comprehension (/10)	–	8.8±1.2	9.0±1.2	nsc
Visual word comprehension (/10)	–	9.4±0.9	9.1±1.1	nsc
Picture naming (/20)	–	19.4±0.9	18.9±1.3	nsc
MMSE (/30)	–	25.2±1.1	20.8±1.9	<0.001c

Note: Values are mean±SD or numbers;

a one-way analysis of variance;

b chi-squared test;

c t-test.

Abbreviations: AD, Alzheimer’s disease; MMSE, Mini-Mental State Examination; ns, not significant; SLTA, Standard Language Test of Aphasia.

Table 2 Examples of the simile comprehension test

Items	Choices
	Correct	Tenor	Vehicle	Magical
Perfume is like a bouquet.	Perfume smells good.	Perfume is a fragrant liquid.	Perfume is a bundle of flowers.	Perfume becomes a bouquet.
A rumor is like a snowball.	A rumor grows rapidly.	A rumor spreads widely.	A rumor is cold and white.	A rumor becomes a snowball.
Wheat fields are like the sea.	Wheat fields are very big.	Wheat fields grow grain.	Wheat fields are full of water.	Wheat fields become the sea.
The earth is like a mother.	The earth creates life.	The earth is a large land.	The earth is a woman.	The earth becomes a mother.

Table 3 Percentages of correct responses on the simile comprehension test and the Token Test in each group

	Normal controls	Very mild AD	Mild AD	P-value
Simile comprehension test	87.5±9.1 (70.0–100.0)	76.3±10.0 (60.0–100.0)	54.8±14.9 (23.3–76.7)	<0.001a
Token Test	98.9±1.0 (96.4–100.0)	96.7±1.8 (92.2–100.0)	94.3±5.1 (82.0–100.0)	<0.001b

Note: Values are mean±SD (minimum–maximum);

a one-way analysis of variance: significant difference between normal controls and very mild AD (P=0.01) and very mild AD and mild AD (P<0.001) with the Tukey HSD;

b one-way analysis of variance: significant difference between normal controls and mild AD (P<0.001) with the Tukey HSD.

Abbreviation: AD, Alzheimer’s disease.

Table 4 Total numbers of error responses on the simile comprehension test in each group

	Normal controls	Very mild AD	Mild AD	P-value
Tenor	44 (59%)	84 (55%)	130 (44%)b	<0.001a
Vehicle	28 (37%)	57 (37%)	90 (31%)
Magical	3 (4%)b	13 (8%)b	73 (25%)c

Note:

a chi-squared test;

b significantly fewer than the predicted value (P<0.01) with the residual analysis;

c significantly more than the predicted value (P<0.01) with the residual analysis.

Abbreviation: AD, Alzheimer’s disease.

Table S1 Questions of the simile comprehension test

Items	Choices
	Correct	Tenor	Vehicle	Magical
A smile is like a flower.	A smile is beautiful and lovely.	A smile is a kind of facial expression.	A smile bears fruit.	A smile becomes a flower.
A problem is like a wall.	A problem obstructs my way.	A problem is a suffering.	A problem surrounds something.	A problem becomes a wall.
A train is like a matchbox.	A train has a square shape.	A train runs with steam.	A train is small.	A train becomes a matchbox.
Perfume is like a bouquet.	Perfume smells good.	Perfume is a fragrant liquid.	Perfume is a bundle of flowers.	Perfume becomes a bouquet.
Cigarettes are like time bombs.	Cigarettes cause physical problems in the future.	Cigarettes smoke badly.	Cigarettes explode on time.	Cigarettes become time bombs.
A demonstration march is like an avalanche.	A demonstration march is a surging crowd.	A demonstration march is a citizen protest.	A demonstration march flows downwards.	A demonstration march becomes an avalanche.
A rumor is like a snowball.	A rumor grows rapidly.	A rumor spreads widely.	A rumors is cold and white.	A rumor becomes a snowball.
Fate is like a phantom killer.	Fate appears unexpectedly.	Fate exceeds one’s will.	Fate can injure a person.	Fate becomes a phantom killer.
Delight is like a fountain.	Delight is a rising emotion.	Delight is a great joy.	Delight has a lot of water.	Delight becomes a fountain.
Hope is like a light.	Hope makes people’s hearts bright.	Hope reflects what people want to happen.	Hope dazzles people’s eyes.	Hope becomes a light.
A suspicion is like a tumor.	A suspicion can spread.	A suspicion is doubt.	A suspicion is a kind of disease.	A suspicion becomes a tumor.
Power is like drugs.	Power drives people mad.	Power dominates people.	Power is a kind of poison.	Power becomes drugs.
Labor is like a prison.	Labor restricts people’s freedom.	Labor is performed by adults.	Labor is a facility to shut people in.	Labor becomes a prison.
A kitten is like a princess.	A kitten is a cute and beautiful animal.	A kitten is a frisky animal.	A kitten is an animal of high rank.	A kitten becomes a princess.
A dictionary is like a gold mine.	A dictionary is a treasure of knowledge.	A dictionary is a book in which one can look up words.	A dictionary is a mountain that produces gold.	A dictionary becomes a gold mine.
Loneliness is like a wintry blast.	Loneliness is very painful.	Loneliness is unsatisfactory.	Loneliness is a strong wind.	Loneliness becomes a wintry blast.
A shock is like electricity.	A shock is transmitted in a moment.	A shock is a kind of force.	A shock is invisible.	A shock becomes electricity.
A referee is like a balance.	A referee is unbiased.	A referee decides victory or defeat.	A referee measures weight.	A referee becomes a balance.
Wheat fields are like the sea.	Wheat fields are very big.	Wheat fields grow grain.	Wheat fields are full of water.	Wheat fields become the sea.
A man is like a wolf.	A man is dangerous and frightening.	A man can never bear a child.	A man is a canine.	A man becomes a wolf.
Roads are like blood vessels.	Road extends everywhere.	Roads are passageways.	Roads are tubes that carry blood.	Roads become blood vessels.
The earth is like a mother.	The earth creates life.	The earth is a large land.	The earth is a woman.	The earth becomes a mother.
Criticism is like a scalpel.	Criticism hurts people sharply.	Criticism points out a problem.	Criticism is used by a doctor.	Criticism becomes a scalpel.
A flying fish is like a grasshopper.	A flying fish can jump.	A flying fish has a strange shape.	A flying fish eats plants.	A flying fish becomes a grasshopper.
Charm is like a magnet.	Charm attracts people’s hearts.	Charm makes people crazy.	Charm attracts iron.	Charm becomes a magnet.
Fog is like a cloak.	Fog obscures objects.	Fog contains many drops of water.	Fog is a type of clothing without sleeves.	Fog becomes a cloak.
A sunset is like a copper coin.	A sunset shines red.	A sunset glows in the evening.	A sunset is money.	A sunset becomes a copper coin.
A theory is like a building.	A theory is a carefully constructed matter.	A theory is a carefully considered matter.	A theory is a type of man-made object.	A theory becomes a building.
Shooting stars are like raindrops.	Shooting stars fall downwards.	Shooting stars burn and disappear.	Shooting stars are composed of water.	Shooting stars become raindrops.
An old man is like a piece of furniture.	An old man does not move.	An old man is a senior citizen.	An old man is in a house.	An old man becomes a piece of furniture.