MDA Publication titled When Neuromuscular Disease Affects the Brain

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QUEST Volume 9, Number 6, December 2002

WHEN

NEUROMUSCULAR DISEASE

AFFECTS THE BRAIN

Some

children with MD have

cognitive or emotional problems, along with physical disabilities.

by Margaret Wahl

Von Wald, director of the Turning Point School in Tucson, Ariz., asks a

child to put a group of cards in a sequence and to tell a story about

them. This kind of task tests aspects of abstract thinking.

If you’re the parent of a child with a neuromuscular

disease, you’ve probably heard something about learning disabilities,

mental

retardation or emotional problems that accompany some of the muscular

dystrophies and related diseases.

But this information is often expressed in vague, general

terms, leaving a parent wondering what specifically has gone wrong,

whether the

child’s school problem is directly related to his neuromuscular disease

or not,

and — perhaps most important — what can be done to help.

Several neuromuscular diseases can involve cognitive

problems (see “Glossary,”

). They most commonly occur in Duchenne, Becker, congenital and

myotonic

muscular dystrophies, and in mitochondrial diseases. Of course, not

every child

with one of these disorders will have cognitive disabilities, but the

risk is

higher than average.

Mitochondrial

Diseases:

Damage to the Brain

Of all the neuromuscular diseases covered in MDA’s program,

those that have to do with the mitochondria — the tiny

energy-producing units tucked inside human and animal cells — are

perhaps the

most mysterious, confusing and challenging for physicians and families.

All cells and the tissues in which they’re located require

energy to function, but some tissues — such as the brain and muscles —

require

more energy than others. That’s probably why defects in mitochondrial

function

hit these areas hard.

There are several types of mitochondrial diseases, and

they all have different characteristics. What’s even more confusing is

that

even when a mitochondrial disease runs in a family, various family

members can

have different symptoms or degrees of severity, even though their

mitochondrial

flaw may be the same.

Neuromuscular disease specialist Tim at Arizona

Health Sciences Center in Tucson says it isn’t so much the

mitochondrial defect

itself that makes the difference in cognitive functioning. Instead, as

with the

congenital muscular dystrophies, it’s the presence or absence of severe

seizures,

as well as two other aspects of mitochondrial disease — strokes

and high

levels of lactic acid in the blood.

“Seizures are a major factor,” says. “For kids with

underlying mitochondrial changes, you have to worry, because seizures

can

damage things even worse.”

Fortunately, says, seizures can often be adequately

controlled with medication. But these medications can themselves cause

some

side effects, which can include sleepiness, confusion, memory problems

and

trouble with vision. The benefits and side effects have to be carefully

weighed

by the doctor and parents and the dose meticulously monitored.

Strokes or “strokelike episodes” occur in some children

with mitochondrial diseases. A “stroke” is the term for an interruption

of

blood supply to the brain, with resulting brain damage, either

temporary or

permanent. Strokes can be caused by either abnormal bleeding in the

brain or an

obstruction to blood flow in the brain.

“There are probably changes in the brain’s blood vessels,”

says. “We know that mitochondrial dysfunction can affect blood

vessels.”

(Other experts say strokelike episodes may sometimes be

seizure-related.)

Unfortunately, there’s little that can be done to prevent or control

these

episodes.

When mitochondria don’t produce energy for cells in the usual

way, energy-producing pathways are altered, leading ultimately to the

buildup

of lactic acid. When enough of this chemical gets into the blood, it

changes

the blood’s acidity level, which leads to a host of unwelcome changes

in body

chemistry. This lactic acidosis isn’t good for the brain,

causing a

variety of cognitive symptoms.

“The body maintains a very strict level of acids and

bases,” says. “Any time that level is affected, it can affect

thinking.”

says a medication called lactulose (brand names

Constilac, Chronulac and others) can sometimes be used effectively to

draw off

some of the acid into the intestines, but that the best approach may be

to try

to prevent lactic acid buildup from occurring in the first place.

Making sure the child’s respiratory function is adequate,

preventing or promptly treating infections, and maintaining good

nutrition can

all help prevent lactic acidosis, says.

“When kids are challenged with something like an

infection, that may make it more difficult for them to stay in

[metabolic]

balance,” he says. Parents have to be on the lookout for signs of

infection and

for cognitive symptoms that suggest lactic acid may be building up.

Diminished

concentration, diminished talking, confusion and irritability are among

those

symptoms.

The brain’s vision-processing cells, as well as the retina

at the back of the eye and the muscles that control eye movements, can

all be

affected in mitochondrial diseases, so vision can be a problem.

Vision therapy may be helpful, as can assistive technology

such as adapted computer screens and computer-operating devices.

Hearing can also be affected, and some children need

hearing aids and/or devices to help them communicate.

Children with mitochondrial diseases and their families

often need referrals to hearing and speech specialists, vision

specialists,

respiratory doctors and therapists, educational specialists, and social

workers

or counselors. (Ask about these specialists at your MDA clinic and

through the

public school system in your area.)

GLOSSARY

attention

deficit disorder: a neurobiological disorder that

interferes with the ability to attend to tasks in an age-appropriate

way and to sustain attention and concentration

attention

deficit hyperactivity disorder: above, combined with

age-inappropriate high activity levels and overly impulsive and

disruptive behavior; may be masked in children with severe mobility

impairment

cognition:

the mental processes by which knowledge is acquired, including

perception, reasoning, judgment, intuition and memory

cognitive

disability: a problem with cognition

Individualized

Education Plan (IEP): a statement for each public

school student with a disability that includes information about the

child’s educational performance and measurable annual goals, plus

program modifications, related services and supplementary aids

to be provided to the child. IEPs are guaranteed by the Individuals

with Disabilities Education Act (IDEA) of 1997.

learning

disability: a disorder that affects the ability either

to interpret what’s seen and heard or to link information from

different parts of the brain

mental

retardation: below-normal intellectual function that

has its cause or onset early in life, with impaired learning, social

adjustment and maturation; tests to assess it are controversial.

seizures

(epilepsy): a recurrent disorder of brain function

marked by sudden, brief attacks of altered consciousness, movement or

sensory phenomena; symptoms range from slight alteration in

consciousness to dramatic loss of consciousness, falling and/or

involuntary muscle contractions.

w

[Guest guest]

Current Issue

| Back Issues

| Stories by Topic

| Research Stories

| Subscribe

| Advertise

QUEST Volume 9, Number 6, December 2002

WHEN

NEUROMUSCULAR DISEASE

AFFECTS THE BRAIN

Some

children with MD have

cognitive or emotional problems, along with physical disabilities.

by Margaret Wahl

Von Wald, director of the Turning Point School in Tucson, Ariz., asks a

child to put a group of cards in a sequence and to tell a story about

them. This kind of task tests aspects of abstract thinking.

If you’re the parent of a child with a neuromuscular

disease, you’ve probably heard something about learning disabilities,

mental

retardation or emotional problems that accompany some of the muscular

dystrophies and related diseases.

But this information is often expressed in vague, general

terms, leaving a parent wondering what specifically has gone wrong,

whether the

child’s school problem is directly related to his neuromuscular disease

or not,

and — perhaps most important — what can be done to help.

Several neuromuscular diseases can involve cognitive

problems (see “Glossary,”

). They most commonly occur in Duchenne, Becker, congenital and

myotonic

muscular dystrophies, and in mitochondrial diseases. Of course, not

every child

with one of these disorders will have cognitive disabilities, but the

risk is

higher than average.

Mitochondrial

Diseases:

Damage to the Brain

Of all the neuromuscular diseases covered in MDA’s program,

those that have to do with the mitochondria — the tiny

energy-producing units tucked inside human and animal cells — are

perhaps the

most mysterious, confusing and challenging for physicians and families.

All cells and the tissues in which they’re located require

energy to function, but some tissues — such as the brain and muscles —

require

more energy than others. That’s probably why defects in mitochondrial

function

hit these areas hard.

There are several types of mitochondrial diseases, and

they all have different characteristics. What’s even more confusing is

that

even when a mitochondrial disease runs in a family, various family

members can

have different symptoms or degrees of severity, even though their

mitochondrial

flaw may be the same.

Neuromuscular disease specialist Tim at Arizona

Health Sciences Center in Tucson says it isn’t so much the

mitochondrial defect

itself that makes the difference in cognitive functioning. Instead, as

with the

congenital muscular dystrophies, it’s the presence or absence of severe

seizures,

as well as two other aspects of mitochondrial disease — strokes

and high

levels of lactic acid in the blood.

“Seizures are a major factor,” says. “For kids with

underlying mitochondrial changes, you have to worry, because seizures

can

damage things even worse.”

Fortunately, says, seizures can often be adequately

controlled with medication. But these medications can themselves cause

some

side effects, which can include sleepiness, confusion, memory problems

and

trouble with vision. The benefits and side effects have to be carefully

weighed

by the doctor and parents and the dose meticulously monitored.

Strokes or “strokelike episodes” occur in some children

with mitochondrial diseases. A “stroke” is the term for an interruption

of

blood supply to the brain, with resulting brain damage, either

temporary or

permanent. Strokes can be caused by either abnormal bleeding in the

brain or an

obstruction to blood flow in the brain.

“There are probably changes in the brain’s blood vessels,”

says. “We know that mitochondrial dysfunction can affect blood

vessels.”

(Other experts say strokelike episodes may sometimes be

seizure-related.)

Unfortunately, there’s little that can be done to prevent or control

these

episodes.

When mitochondria don’t produce energy for cells in the usual

way, energy-producing pathways are altered, leading ultimately to the

buildup

of lactic acid. When enough of this chemical gets into the blood, it

changes

the blood’s acidity level, which leads to a host of unwelcome changes

in body

chemistry. This lactic acidosis isn’t good for the brain,

causing a

variety of cognitive symptoms.

“The body maintains a very strict level of acids and

bases,” says. “Any time that level is affected, it can affect

thinking.”

says a medication called lactulose (brand names

Constilac, Chronulac and others) can sometimes be used effectively to

draw off

some of the acid into the intestines, but that the best approach may be

to try

to prevent lactic acid buildup from occurring in the first place.

Making sure the child’s respiratory function is adequate,

preventing or promptly treating infections, and maintaining good

nutrition can

all help prevent lactic acidosis, says.

“When kids are challenged with something like an

infection, that may make it more difficult for them to stay in

[metabolic]

balance,” he says. Parents have to be on the lookout for signs of

infection and

for cognitive symptoms that suggest lactic acid may be building up.

Diminished

concentration, diminished talking, confusion and irritability are among

those

symptoms.

The brain’s vision-processing cells, as well as the retina

at the back of the eye and the muscles that control eye movements, can

all be

affected in mitochondrial diseases, so vision can be a problem.

Vision therapy may be helpful, as can assistive technology

such as adapted computer screens and computer-operating devices.

Hearing can also be affected, and some children need

hearing aids and/or devices to help them communicate.

Children with mitochondrial diseases and their families

often need referrals to hearing and speech specialists, vision

specialists,

respiratory doctors and therapists, educational specialists, and social

workers

or counselors. (Ask about these specialists at your MDA clinic and

through the

public school system in your area.)

GLOSSARY

attention

deficit disorder: a neurobiological disorder that

interferes with the ability to attend to tasks in an age-appropriate

way and to sustain attention and concentration

attention

deficit hyperactivity disorder: above, combined with

age-inappropriate high activity levels and overly impulsive and

disruptive behavior; may be masked in children with severe mobility

impairment

cognition:

the mental processes by which knowledge is acquired, including

perception, reasoning, judgment, intuition and memory

cognitive

disability: a problem with cognition

Individualized

Education Plan (IEP): a statement for each public

school student with a disability that includes information about the

child’s educational performance and measurable annual goals, plus

program modifications, related services and supplementary aids

to be provided to the child. IEPs are guaranteed by the Individuals

with Disabilities Education Act (IDEA) of 1997.

learning

disability: a disorder that affects the ability either

to interpret what’s seen and heard or to link information from

different parts of the brain

mental

retardation: below-normal intellectual function that

has its cause or onset early in life, with impaired learning, social

adjustment and maturation; tests to assess it are controversial.

seizures

(epilepsy): a recurrent disorder of brain function

marked by sudden, brief attacks of altered consciousness, movement or

sensory phenomena; symptoms range from slight alteration in

consciousness to dramatic loss of consciousness, falling and/or

involuntary muscle contractions.

w