Often, Australians get mocked for talking through their noses.  But, jokes aside, too much nasal resonance – “hypernasality” – is a real problem for some, regardless of nationality.

Why?

Hypernasality causes muffled speech.  It can affect articulation, stress and intonation, and breathing during speech.  Together, these things can make speech hard to understand.  Typical speakers are up to 15% easier to understand than people with hypernasal speech (Watson & Plichta, 2011).

What causes it?

Usually, soft palate problems cause hypernasality.  When we say nasal sounds, like “m”, “n” and “ng”, our soft palate stays down.  This lets air and speech sounds come up through our noses.

When we say other speech sounds, our soft palate should lift up and touch the back of the throat. This blocks the air and sounds from coming up through our noses.

For some, soft palates don’t rise when they should.  For others, soft palates might not rise enough, or be long or strong enough to block off their noses.

Who’s affected?

Up to:

• 95% of people with traumatic brain injury causing dysarthria; and
• 94% of people with a stroke causing dysarthria,

are hypernasal (Theodoras et al., 1994).  This is due to to damage to the upper and/or lower neurons supplying the muscles of the soft palate and throat.

Some people are born with soft palates that don’t work.  Others have no physical problems but speak through their noses: a bad habit.

Some people with hypernasal speech present with accent issues.  In some languages, lots of sounds are made through the nose.  Speakers of English as a second language may struggle to make sounds through their mouths if they make similar sounds through their noses in their first languages.

How is hypernasality measured?

With difficulty.

The best way to measure hypernasality is with perceptual ratings carried out by clinicians.  One example is the “Direct Magnitude Estimations” (e.g. Zraick & Liss, 2000).

An alternative is using a machine to measure nasal airflow, e.g. with a Nasometer.

Good research uses both kinds of measures.  But, in practice and in research, the outcomes often clash!

What can we do about it?

Surgery may be an option for some.  Others may benefit from palatal lifts and prosthetics.

We have limited evidence about speech pathology treatments for hypernasality:

• continuous positive airway pressure (CPAP) therapy may help some people (e.g. Cahill et al, 2004);
• behavioural speech treatments for rate, volume or articulation may reduce hypernasality in some cases (e.g. Yorkson & Beukelman, 1981; McHenry & Liss, 2006); and
• LSVT LOUD treatment may be a suitable treatment option for some individuals with hypernasality (see below).

Common therapy goals include:

• recruiting and strengthening the muscles of the soft palate in speech tasks;
• increasing volume, articulation accuracy, and mouth-opening; and
• reducing speech rate.

Clinical bottom line

Some people are hypernasal.  It can make them hard to understand and cause distressing social and professional problems.

Evidence-based treatments are available.  None is perfect.  Behavioural speech therapy may benefit clients when surgery and/or prosthetics are unsuitable.

No treatment works for everyone.  Evidence-based treatments should be tailored to the client’s impairments, needs, goals and preferences.

Treatments may include trial and error.  We must measure progress and outcomes and to stay up to date with new research.

Principal Source: Wenke, R.J., Theodoros, D., Cornwell, P. (2010). Effectiveness of Lee Silverman Voice Treatment (LSVT) on hypernasality in non-progressive dysarthria: the need for further research. International Journal of Communication Disorders, 45(1), 31-46.

Image: http://bit.ly/1jZ1TuF