Talk:Tourette syndrome/Archive 5

message: *Some muddles in "Epidemiology" (the current version of the following list applies to an older version of the main article):
#The current wording says Tourette was "rare" but doesn't cite information that supports this assertion, at least to the satisfaction of the EU's definition of "rare disorder", which is 0.5 per 1000 prevalence or less; see Rare Disorders. One way to fix this is to remove the word "rare" (it used to say "rare disorder", but even the word "rare" alone, is questionable here). A better way to fix it is to cite an older reference with a lower prevalence estimate.
#:I'm not planning to engage in a point-by-point rebuttal of each point on your "list", but as an example of the problems with many of the issues you've raised, I'll address your first point here, and the rest later in a summary.  The sources for the statement that Tourette was once considered rare (before and after recent changes) were the Bagheri and the Zinner articles.  First, here are the exact quotes from those articles:
#::Bagheri:  "Once believed to be rare, Tourette's syndrome is now known to be a more common disorder ..."
#::Zinner:  "Until recently, TD was considered a very rare psychiatric diagnosis that was witnessed perhaps once in a medical professional's life.  Although no longer considered rare, this disorder often is undetected, partly because of its diverse expression."
#:Second, although you're applying a specific definition of "rare", and I can cite whatever is needed to meet any definition of rare, both sources do support "0.5 per 1000 prevalence or less", as both of them cite a range which includes .5 per 1000.  The article was meticulously and accurately cited, and I will similarly cite everything else you've requested, even if it is already cited, and is common knowledge.  I'll address the rest of your points in a summary, so that this section doesn't become unnecessarily long and unreadable.  SandyGeorgia (Talk) 22:40, 25 May 2007 (UTC)
replies: text: Eubulides 07:14, 25 May 2007 (UTC)
replies: text: I switched the above section to numbered rather than bulleted, so I can refer to each point below without having to chop the text above.  SandyGeorgia (Talk) 08:08, 24 May 2007 (UTC)

text: *Added the best quote I could find which related to epidemiology, from Leckman Lancet paper.  SandyGeorgia (Talk) 18:14, 26 May 2007 (UTC)
thread_title: Epidemiology

message: I'm still processing through all of my sources, but want to post some summary info today.  The proposal (below) has too many mistakes to work with; I suggest we focus on improving the text currently in the article, which is accurate.  
Also, since the current text has no mistakes, I also hope Eubulides will be comfortable taking the time to sort things out correctly, particularly since I want to do more reading, track down some pending issues (like what's going on with Kadesjo), and I have pending travel.  There's no need to rush through this, since the current text has no glaring problems.
At any rate, here's a summary vis-a-vis the list of "muddles" in the Epidemiology section above:
;Done, although don't agree were necessary.  
I disagree with some of your statements and requests for citations on the following, but I made these changes anyway:
*1 (TS was once thought to be rare)
*2, 3 and 4 on prevalence numbers and studies.
*8, (in children, not sure it matters, since TS is a condition of childhood onset, but clarified)
;Done, agreed.  
I agree with you that changes were warranted on the following items, and I made the changes.
*6 and 9, bracket the 53,000 to 530,000
*14, three to four males to females, clarified in the citation
*20, moved the first sentence in Epidemiology to Diagnosis, although that info will need to be worked back in to an analysis of all factors affecting prevalence in TS, when that is later added.
;To do, factors affecting prevalence estimates
*7, Your statement that prevalence rates have changed because of DSM-IV-TR is incomplete, and not entirely accurate; I plan to write a paragraph summarizing the issues affecting prevalence estimates.  You are correct that it should be clarified, since there is such a range.  I want to keep this paragraph short and not too statistical.
;To do, Kurlan
How to deal with Kurlan needs to be worked out.  There are numerous pros and cons to his work (selection bias in sample, but perhaps the only study to account for current diagnostic criteria — I need to check that).  Paragraph needs to be sorted out and completed to briefly discuss those factors, since his numbers get good play in the literature and need to be dealt with.
*10, 11, 12, 13, 22 and 23 — all Kurlan points to be dealt with in a re-write (not all of which I agree with, but will be sorted out)
**I added some explanation now of Kurlan's higher results.  They did several things right (that most other studies didn't do), that result in higher prevalence:  1) large sample size, 2) highly trained examiners, 3) multiple informants (teachers, parents, examiners), 4) direct classroom observation for a long enough time period to avoid tic suppression, and 5) excluded DSM-IV impairment criterion to reflect current DSM-IV-TR diagnostic criteria.  I'm not sure any other study did all of that, but I'm still reviewing.  On the other hand, their study may have been affected by selection bias, in that respondents with tics were more likely to participate in the study.  However, Kurlan's results agree with Mason's results.  Several pros, several cons, a study that did many things right, gets a lot of publicity, and can't be entirely disounted, although we can later balance this text by analysis of other *good* studies (not some of the older junk with serious methodological issues that Hirtz included).  I hope to have a better sense of another study to include for balance after doing still more reading.  I'm still not sure what to do about Hirtz's 9.4, though, since I don't find it in the Kurlan text, so am reporting the numbers as the study reports them; we can't do original research.  SandyGeorgia (Talk) 19:15, 26 May 2007 (UTC)
replies: text: *Added the best quote I could find which related to epidemiology, from Leckman Lancet paper.  SandyGeorgia (Talk) 18:14, 26 May 2007 (UTC)
thread_title:  Summary of list 

message: I'm still processing through all of my sources, but will post some summary info today.  The proposal has numerous mistakes, and is wrong or misleading in many areas.  The current text in the article may need editing for clearing up some issues (Kurlan, factors affecting prevalence numbers in TS) and decision about what units to report, but at least it's not wrong, so I suggest we stay focused on the current text, which is accurate.
----
Tourette syndrome was formerly thought to have a prevalence well under 1 per 1,000 school-age children.Burd L, Kerbeshian J, Wikenheiser M, Fisher W. A prevalence study of Gilles de la Tourette syndrome in North Dakota school-age children. J Am Acad Child Psychiatry. 1986 Jul;25(4):552–3.  
*Not necessarily wrong, but not useful.  Can do much better. Decide if we want to go into numbers here (at all), or leave them for History.  (Gave enough to reference old examples of "rare", without giving so much that we get into territory of History section.)
However, multiple studies published since 1995 demonstrate that the prevalence is higher than previously thought, though part of this is merely due to changes in diagnostic criteria. 
*Incomplete, misleading.  In fact, I think it's completely wrong, since most of the studies cited are DSM-IV.  I'm still doublechecking, but I suspect that Kurlan is the only study that accounted for DSM-IV-TR (no impairment), which makes his numbers more accurate in that sense than any others, and explains part of the difference between his numbers and others.  The proposed text gives no mention of increasing awareness, that older estimates were affected by ascertainment bias, the direct interview and observation (better methods) are used in current studies.  Unsourced.  Why 1995? Will address this better later with a summary paragraph of issues affecting prevalence numbers in TS studies.
A study of 38,586 5- to 15-year-old children in Sweden found a prevalence rate of 1.5 per 1,000.Kadesjö B, Gillberg C. Tourette's disorder: epidemiology and comorbidity in primary school children. J Am Acad Child Adolesc Psychiatry. 2000 May;39(5):548–55.  
*Wrong (??).  Where did those numbers come from ? I have two sources that report Kadesjo N=435, although I don't have the study.  These numbers aren't reported in TS reviews — what's the deal?  I will need to find out.
*Best to take care with discussion of specific studies, lest we end up writing a tome on the pros, cons, methodological issues in each.
A study of 1,596 8- to 17-year-old children in New York found that over 190 per 1,000 children in regular education had tics, and almost 40 per 1,000 met the diagnostic criteria for Tourette syndrome. ((??The "40" is much larger than the upper bound of "10" below, and is also much larger than the 9.4 that Hirtz et al. summarize Kurlan as reporting. Also, shouldn't we be reporting total statistics, not regular-ed? What sort of self-selection happened? What is going on here??)) The children with tic disorders in the latter study were usually undiagnosed.Kurlan R, McDermott MP, Deeley C, et al. Prevalence of tics in schoolchildren and association with placement in special education. Neurology. 2001 Oct 23;57(8):1383–8.  
*Not wrong, but extremely confusing, incomplete and not useful.  We can do better, if we decide to use Kurlan at all.  Kurlan needs to be dealt with, separately, since he's widely quoted.  The pros and cons would need to be discussed, including sampling bias, but he did account for no impairment, in line with DSM-IV-TR.
As these two examples suggest, larger studies, which have better confidence intervals, have found lower prevalence rates.
*Completely wrong, don't even know where this notion comes from, uncited, original research, synthesis, and oversimplification considering all factors.  Sample sizes and prevalence, for example :
**Apter, 28,037 .4/1000 not on children, very old study, doesn't use DSM-IV-TR, numerous acknowledged issues, not even a contender.
**Khalifa, 4,479 6/1000
**Kurlan, 1596 8-15, or 9/1000 (has to be worked out, not clear)
**Hornsey, 918, 8/1000
**Peterson, 776, 3/1000
**Kadesjo, 435, 11/1000
*Numbers above show no correlation between sample size and prevalence, and there are far too many confounding factors in each study to make such an oversimplication of the numbers.
A 2007 review of the strongest evidence available concluded that the data were insufficient to accurately estimate the prevalence of Tourette's in the US.Hirtz D, Thurman DJ, Gwinn-Hardy K, Mohamed M, Chaudhuri AR, Zalutsky R. How common are the "common" neurologic disorders? Neurology. 2007 Jan 30;68(5):326–37.  
*Wrong on too many counts to detail here; further, Hirtz is not a particularly useful analysis because of their unselective method of choosing studies, and their criteria which penalized TS for the change to DSM-IV-TR.  Nonetheless, the average they reported was 3.5 for one group of studies, 7.2 for another (they gave undue weight to first group because of their method).  Results and methodology misrepresented.  Not al all "stongest evidence available", and at any rate, their numbers are exactly within the range of all Scahill numbers, so there is no need to muddy up the text with old numbers and dubious interpretations of a confusing methodology.
A commonly suggested range for school-age children is between 1 per 1,000 and 10 per 1,000; the lower number yields an estimate of 53,000 school-age children with Tourette's in the United States, based on 2000 census data, while the higher yields an estimate of 530,000.Scahill L, Williams S, Schwab-Stone M, Applegate J, Leckman JF. Disruptive behavior problems in a community sample of children with tic disorders. Adv Neurol. 2006;99:184–90. 
*To clear up confusion, Scahill's text (and other sources) specifically mention the 1 to 11 range, while his example uses 1 to 10; this is very clear, and we shouldn't be doing the math ourselves or changing what the sources say.  Best to stick to reporting what reliable sources wrote, which is 1 to 11 consensus range, 1 to 10 used for sample numbers.
...males are affected 2 to 4 times more often than females.Zinner (2000).
*Not useful, not consensus, one source only, we can do better with info I dug up above. (Done).
SandyGeorgia (Talk) 14:57, 26 May 2007 (UTC)
thread_title: Problems with proposal

message: Here's what I did for now, while we work on finetuning the rest:
:Tourette syndrome has historically been described as rare, with less than 1 person in 1,000 having the condition.  However, multiple studies published since 2000 demonstrate that the prevalence is much higher than previously thought, and that Tourette syndrome can no longer be considered rare.  A large, community-based study of 1,596 school-age children suggested that over 19% of school-age children have tics, with almost 4% (40 per 1,000) of children in regular education fulfilling the diagnostic criteria for Tourette syndrome.  The children with tic disorders in that study were usually undiagnosed;Kurlan R, McDermott MP, Deeley C, et al. Prevalence of tics in schoolchildren and association with placement in special education. Neurology. 2001 Oct 23;57(8):1383–8.  other studies place the prevalence of TS in school-age children much lower—the emerging consensus is between 1 and 11 per 1,000 (.1% to 1.1%).  A prevalence rate of 1 per 1,000 yields an estimate of 53,000 school-age children with Tourette's in the United States, based on 2000 US census data, while an estimate of 10 per 1,000 would yield an estimate of 530,000 school-age children with TS.Scahill L, Williams S, Schwab-Stone M, Applegate J, Leckman JF. Disruptive behavior problems in a community sample of children with tic disorders. Adv Neurol. 2006;99:184-90. 
This:
*1) changes the per 10,000 to a per 1,000 number, for consistency.
*2) reports percentage as well as per 1,000, hopefully to help keep us all on the same page
*3) combines the Bagheri, Zinner mention of older prevalence into one "merged" ("less than 1 per 1,000) number to avoid being burdered by excess detail in an outdated number and to avoid sorting out the differences in what they report
*4) removes the older Scahill study, since the newer ones I have update them anyway, and using only one report gives better consistency with less explaining
*5) adds in the 1 to 11 Eubulides was concerned about
*6) brackets the 53 to 530
*7) introduces new numbers which provide context for the high Kurlan estimate
*8) changes the wording "rare disorder" to just rare, to hopefully help avoid confusion with formal definitions of rare disorders.
There's still more to be done, but is that a good start for now, without overburdening the text with a lot of numbers and stats?  SandyGeorgia (Talk) 21:03, 24 May 2007 (UTC)
thread_title:  Temporary 

message: A couple of excellent edits were introduced over the last few days (more below) that combined sentences in ways that only one reference was needed or clarified wording.  The order/flow can be improved (it got quite twisted around in the last round of debate here), but not at the cost of introducing errors.  In addition to the errors introduced over the last few days (see below), here is a list of concerns about the proposed text:
*I don't know where this statement is coming from; even Kurlan recognized his sample was biased towards special ed, and I don't recall any such statement as this one in his two papers. I don't recall him drawing this conclusion, considering the sampling issues (please provide the quote if I'm wrong), but this looks like synthesis and a misinterpretation, considering the limitations of his sampling methods:  "Special education schoolchildren are more likely to meet diagnostic criteria for Tourette's than regular education schoolchildren are."Kurlan R, McDermott MP, Deeley C, et al. Prevalence of tics in schoolchildren and association with placement in special education. Neurology. 2001 Oct 23;57(8):1383–88. 
::*I don't have the full paper. But from the abstract you get 
:::"RESULTS: Twenty-seven percent of 341 students classified as receiving special education (SpEd) had tics compared with 19.7% (p = 0.008) of 1,255 students in regular classroom programs (RegEd). The weighted prevalence estimates for tics were 23.4% in SpEd and 18.5% in RegEd. A higher percentage of students in SpEd (7.0%) met diagnostic criteria for TS than students in RegEd (3.8%; p = 0.01)." (my emphasis)
::I assume, from your comments, that the article goes on to discuss (or other reviewers have) whether those results can be regarded as a fair interpretation of the population at large. Colin°Talk 08:58, 14 June 2007 (UTC)
thread_title: Another review of proposed draft

message: Problems in the edits of the last few days; it might be premature to move forward to yet another draft, which introduces error on top of error.  The edits of the last few days introduced some vague and choppy prose, some potentially misleading text, unnecessarily deleted citations.  
Colin, on your comments above, I've got to first focus on working back through some of the edits done in the last two days.  The Hirtz review is just not useful; as a meta-analysis, one of its fundamental flaws is that it will be weighted towards Apter (by the large sample size), which has dramatic, fundamental known errors (we haven't even started on their claim that 8% of people with TS have ADHD and that the male/female ratio is essentially equal; such are the known errors found in Apter, because people had good reason to lie.  Since it's the largest study, it just doesn't allow Hirtz to provide for a good meta-analysis).  Preferable to reflect more studied analyses of newer data, which are available.  Yes, several publications use the word "consensus" on epidemiology. Eubulides, which of the three cited Scahill publications do you have and not have, so I can be more careful to provide exact quotes, and I'll see if I can locate online copies anywhere? 
Removing Kurlan will just create a future headache, because it will be re-added as it is so widely quoted and reported.  Better to deal with it than just leave it out. It has a problem (selection bias) that should be addressed, but there is no strong evidence that its prevalance is wrong, and it validates Mason and is within the range of several other studies.  This 4 to 17 Roberson number is now coming up; I can't see any reason to broaden the range even further than current consensus (to 17 instead of 11) because Robertson suggests it, when several other publications confine the range more reasonably.  Robertson just isn't subject to the same broad peer review and consensus that TSA Medical Advisory Members are.  There seems to be still be ongoing misunderstandings here on Kurlan; his numbers aren't at all out of range, we just haven't gotten to the bottom of why he reports percentages one way, while Scahill and Hirtz each convert his percentages to a prevalance, which is completely within range of other studies and consensus.  Kurlan's number is 8, as reported by Hirtz and Scahill, which is within the 1 to 11 and the 4 to 17.  His work has not been discredited (rather, viewed in context), and the reason it warrants mention is specifically that it has been one of the few broad studies to use trained technicians for observation (and since such wording was used in the literature, it is not a "peacock" term ... it's a studied analysis of what he did right that former studies got wrong).
In general, I see several potential misstatements and misquotes, and choppy prose which introduces vagueness, so I'll get through the list below to first correct the current text as soon as I can.   SandyGeorgia (Talk) 00:55, 14 June 2007 (UTC)
replies: text: I'm working on it in my sandbox, and will propose a new draft here once I get out all the kinks that are still troubling me.  In addition to working out some subtle errors that are introduced/proposed, I also believe the issues in all of the studies should be explained before the numbers are presented, so the discrepancies among estimates and rising prevalence rates can be understood in context.  IMO, explaining the issues affecting TS studies after presenting the numbers will leave the uninitiated reader even more confused about the rising prevalence rates. SandyGeorgia (Talk) 18:21, 16 June 2007 (UTC)
thread_title: Older edits to review and fix

message: I'm honing in on the registry source, but there is still one little subtlety in the proposed draft that is troubling me.  What we have is technically accurate, but still may be subtly misleading to the reader.  If you look at my sandbox comments on the Khalifa study, you see that we have a large study, that missed cases, that insisted upon impairment (strictly interpreted DSM-IV criterion), yet finds a prevalence in that "remarkably consistent" range of 6–8.  The draft says:
:There are discrepancies across current and prior prevalence estimates due to several factors:  ascertainment bias in earlier samples drawn from clinically referred cases, assessment methods that may fail to detect milder cases, and differences in diagnostic criteria and thresholds.  As the diagnostic threshold has moved towards milder cases with the removal of the impairment criterion in DSM-IV-TR, the result is an increase in estimated prevalence.
This is true to Scahill, but he also goes on to explain that Khalifa tried to address the mild/impairment issue, by insisting on impairment.  At least one other newer study (Wang) found 5.6/1,000 using DSM-IV, and I believe there are others.  I don't want to get into discussing individual studies like Khalifa or Wang again, and don't want to grow the text too much, but my concern is that the text subtly implies that much of the increase in prevalence is due to the DSM change, when in fact, even studies with impairment are honing in on that range.  I wish we could fix this with just one or two words or phrases from the Scahill letter (PDF).  SandyGeorgia (Talk) 18:23, 17 June 2007 (UTC)
replies: text:  How about something like ... the result is an increase in estimated prevalence, although newer studies using the old impairment criterion of DSM-IV but better sampling and assessment methodology also report consistently higher prevalence.   ??  SandyGeorgia (Talk) 18:38, 17 June 2007 (UTC)
thread_title: Khalifa concern