DYSLEXIA

Dyslexia

Dyslexia

Dyslexia refers to a disturbance in the acquisition of reading and spelling skills. Sometimes the term specific reading disorder is used instead of dyslexia. It is a hereditary disorder with an incidence of 2-12% (Elbro et al., 1998; Pennington & Lefly, 2001; Scarborough, 1990). Children with at least one dyslexic parent, however, have a considerable higher risk; they have between 32 and 68% chance of developing dyslexia (Elbro et al., 1998; Pennington & Lefly, 2001; Scarborough, 1990). Several studies have found a sex bias towards males for the incidence of dyslexia; more than twice as many males than females are affected (Miles et al., 1998; Rutter & Yule, 1975; Sauver et al., 2001; Flannery et al., 2000; Shaywitz et al., 1990).

However, it is not clear whether male children are biologically predisposed to developing dyslexia (Flannery et al., 2000), or are more commonly diagnosed due to referral bias (Shaywitz et al., 1990). Controversies have led to several definitions and theories concerning the underlying cause of dyslexia. These controversies are due to heterogeneity in the behavioural profile of dyslexia: symptoms of dyslexia change with age (Snowling, 2000), co-occurring disorders lead to a change in behavioural manifestations (Snowling, 2000), and the behavioural manifestation of dyslexia differs across languages (Snowling, 2000; Vellutino, 2004).

Case study

“Ann” is a fourteen-year-old female diag- nosed with dyslexia. For the past few years she had been in inclusion classes and receiving remedial reading with the reading specialist in her school district two times per week. She had completed the 4th level in the Wilson Reading Program and was not receiving remedial tutoring during the time that she was completing IM treatment.

At the initial pretesting session, the Gray Oral Reading Test-4 was administered to assess her reading rate, accuracy, fluency, and comprehension. Ann broke down in tears at her inability to read the simple pas- sages, but she then collected herself and chose to continue the testing with a renewed strength and hope that Interactive Metronome (IM) treatment would be of value in helping her to read better. Ann found her hope in IM through the positive experiences of friend who had completed treatment the previous summer with a 1.5- year gain in reading comprehension fluency and comprehension.

Ann's initial level of functioning in grade equivalency was a 1.4 in reading rate, 2.2 in accuracy, 1.4 in fluency, and <1.1 in com- prehension according to the GORT-4. After observing Ann's stress from being confronted with her severe reading deficits on the GORT-4, it was decided to adminis- ter the IM pretest Long Form Assessment during a separate second session. Wearing headphones, Ann tried to match the rhyth- mic beat she heard with specific hand and foot motions using hand and foot triggers.

The IM system used the data captured by the triggers to calculate and record how closely Ann was able to synchronize her motions to the rhythmic reference beat. The results were then displayed as a numerical score in milliseconds (ms) that provided a measure of her basic neurological and motor planning, ...