Table 2 Clinical impressions

NPC Participant 1

Participant 1 is a 14 year 8 month old adolescent boy, who was evaluated 3 months after his participation in our behavioral study. He was diagnosed with NPC in 2005 and is currently on the following medications: Zavesca (miglustat), Depakote (divalproex sodium), Keppra (levetiracetam), and Coumadin (warfarin). He has a history of seizures onsetting at age 14. Parental reports indicate clumsiness and unclear speech, which were also observed in the lab. The participant currently receives occupational and speech therapy. He is home-schooled due to the frequency of his seizures. A routine hearing screen performed at the lab revealed mild high frequency hearing loss (i.e. 4,000 Hz tones were not detected at <60 dB & 2,000 Hz tones were not detected at <45 dB). A routine vision screen (Snellen chart) revealed 20/20 and 20/30 visual acuity, in the right and left eyes respectively.

Overall intellectual functioning, as measured by the Full Scale IQ on the WASI-II, was estimated in the mild to moderately impaired range (FSIQ = 76). His Verbal Comprehension Index score fell in the mildly impaired range (VCI = 82) and was somewhat higher than his Perceptual Reasoning Index score which fell in the mild to moderately impaired range (PRI = 74); however this difference was not statistically significant. The examiner noted that on several trials of the Block Design subtests of the PRI, the participant was able to reproduce the modeled design, however with a 90° rotation. The examiner noted that the participant performed much better when verbal items called for short succinct answers. This likely contributed to his higher Similarities score, as several of the relationships probed by the subtest can be addressed with one word explanations, as compared to the Vocabulary subtest which requires a more lengthy, developed explanation. Further, the examiner notes that speech was effortful and may have affected performance, with the current scores underestimating the participant’s true abilities. The examiner also noted that the participant appeared fatigued and yawned frequently towards the end of the testing session.

NPC Participant 2

Participant 2 is a 14 year 10 month old adolescent boy, who was evaluated 3 months after his participation in our behavioral study. He was diagnosed with NPC in 2005; this patient has a I1061T and M1142T mutation on exons 21 and 22. He is currently on the following medications: Trileptal (oxcarbazepine) and Zavesca (miglustat). He has a history of seizures with the last seizure occurring 10 months prior to testing. The participant currently receives occupational therapy, speech therapy, and has a 1:1 aide at school. A routine hearing screen performed at the lab revealed mild high frequency hearing loss (i.e. 4,000 Hz tones were not detected at <60 dB). A routine vision screen (Snellen chart) revealed 20/60 visual acuity in both eyes.

Overall intellectual functioning, as measured by the Full Scale IQ on the WASI-II, was estimated in the moderately impaired range (FSIQ = 62). His Verbal Comprehension Index score was in the mild to moderately impaired range (VCI = 69) and somewhat higher than his Perceptual Reasoning Index score which fell in the moderately to severely impaired range (PRI = 58); however, this difference was not statistically significant. The examiner observed that the participant had motor difficulties when manipulating the blocks used in one of the PRI subtests (Block Design). Poor articulation was noted at times, but this was not believed to have interfered with testing.

NPC Participant 3

Participant 3 is an 11 year 1 month old boy, who was evaluated on the same day as his participation in our behavioral study. He was diagnosed with NPC in 2013. He is currently on the following medications: Keppra (levetiracetam) and Zavesca (miglustat). He has a history of seizures, including a 4 day hospitalization due to seizure-like activity. He has suffered a concussion that did not render him unconscious. The participant currently receives occupational therapy and academic help with reading and math in a specialized classroom setting at school. Normal hearing was confirmed through a routine hearing screen performed at the lab. A routine vision screen (Snellen chart) revealed 20/50 and 20/30 visual acuity, in the right and left eyes respectively.

Overall intellectual functioning, as measured by the Full Scale IQ on the WASI-II, was estimated in the moderately impaired range (FSIQ = 63). His Verbal Comprehension Index score fell in the mild to moderately impaired range (VCI = 72) and was significantly higher than his Perceptual Reasoning Index score which fell in the moderately to severely impaired range (PRI = 56). The examiner noted that the participant had much difficulty with Block Design subtest of the PRI, often asking whether the designs presented to him were ‘even possible’. On the Matrix Reasoning subtest of the PRI, the participant could not correctly answer any of items at or beyond the starting point for his age and testing here was quickly discontinued. The examiner notes that the participant was pleasant, friendly, and cooperative testing session.