These days, many health
providers are quick to diagnose patients with “post concussion syndrome” if
persistent symptoms are reported after a known or suspected mild traumatic
injury (also known as concussion). Interestingly, I have seen this diagnosis given
to patients who do not meet any operational definition
of concussion and/or who are less than three months post-injury.
While diagnosing “post concussion syndrome” in patients who were never
concussed or who are not yet in the persistent symptom phase is problematic,
another problem is that many providers fail to realize is that there are no
current consensus-based diagnostic guidelines for a condition with that exact
name.
To be precise, the
correct diagnostic terms are post-concussional syndrome (PCS) per the
International Classification of Diseases-10th edition (ICD-10, 1992) and
post-concussional disorder (PCD) per the Diagnostic and Statistical Manual of
Mental Disorders-IV (APA, 1994). These criteria are listed at the end of this
blog entry in Appendix A.
While this may seem like
a purely semantic argument at first, it is actually a distinction with a significant difference. To
begin with, whenever a medical or psychological condition is diagnosed, one
needs to know the specific criteria required to make the diagnosis. Without
such criteria, diagnostic errors rise and confusion results when attempts are
made to communicate about a particular condition. This is why, for example,
there are clear and specific criteria for diagnosing multiple sclerosis (Polman
et al., 2005).
Since there are many conditions that can initially present like
multiple sclerosis, the use of formal diagnostic criteria helps improve
diagnostic accuracy. The same holds true for all other medical and psychological
conditions. That is, criteria should to be used to establish a diagnosis and
the criteria should help distinguish the condition of interest from similar
conditions.
With this in mind, how can a diagnosis of “post concussion
syndrome” have any real meaning if there are no current formal diagnostic
criteria that anyone to refer to? The answer is that it can’t. So we then must
turn to the diagnostic criteria for PCS and PCD and examine their utility.
Serious problems with
the definitions
The first question one
may naturally ask is since there are two different criteria sets, how well do
they agree when applied to actual patients? This question was specifically
evaluated by Boake et al. (2004, 2005) who only found “limited agreement” to
put it nicely. The reason for the limited agreement mainly centers around very
different diagnostic thresholds. That is, after a concussion has been
established, a PCS diagnosis only requires a patient to report a few symptoms
to meet the diagnostic threshold. This is a very liberal diagnostic
threshold since all of the symptoms are non-specific to brain injury. That is,
the symptoms listed in the criteria set are often endorsed by normal controls
without brain injury (e.g., college students), patients with major depressive
disorder, patients with chronic pain, and personal injury claimants with no
history of brain injury.
In fact, as McCrea (2008) summarized in his text, many
of these groups report such symptoms at higher frequencies than patients with a
history of mild traumatic brain injury (MTBI). In a fascinating study by
Iverson (2006), he showed that about 90% of patients with a depressive
disorder (with no recent history of brain injury) met liberal self-report
criteria for postconcussional syndrome.
Although patients may
state that their symptoms began after the concussion, this is not always
accurate since patients may exaggerate symptoms (particularly in compensation
based claims), may unintentionally misattribute symptoms from another condition
(e.g., whiplash, psychological conditions) to brain injury, or may
underestimate the degree to which symptoms were present before the injury and
overestimate the degree to which they were present afterwards due to
expectations that people have about symptoms one should experience after a
concussion (Mittenberg et al., 1992).
Turning to DSM-IV
criteria, a diagnosis of PCD requires the presence of cognitive difficulty on
objective tests. Objective cognitive testing is often not feasible or practical
for physicians, nurse practitioners, or other health care providers who do not
have training in objective cognitive assessment. The other problem is that
numerous prospective research studies consistently show that patients with a
single mild TBI (and in some studies, multiple MTBIs) do not show
evidence of cognitive impairment more than three months post injury (Belanger
et al. 2005a, 2005b; Binder et al, 1997a, 1997b; Bleiberg et al., 2004; Dikmen
et al., 1995; Frenchman et. al, 2005; Iverson, 2005; Larrabee, 1997; Pellman et
al., 2004; Schretlen et al., 2003).
Therefore, it is not all that likely that
objective testing will reveal evidence of cognitive impairment more than three
months post-injury, particularly when factors such as effort and motivation
during testing are accounted for and when other possible etiologies are considered
such as psychiatric disorders. This is important because DSM-IV requires that a
diagnosis of PCD is not given if the presentation can be explained by another
mental disorder.
Since one criteria set
is overly liberal (ICD-10) and another is overly conservative (DSM-IV), it
should not be surprising that Boake at al. (2005) found that only 11% of TBI
patients (90% mild, 10% moderate) met PCD criteria whereas 64% of patients met
PCS criteria. It should be noted that the researchers used a liberal threshold
to define a cognitive difficulty (one standard deviation below the mean) since
the DSM-IV criteria provide no guidance in this area. This liberal threshold
results in a higher degree of false positive classifications since many normal
controls obtain scores one standard deviation below the mean.
Another problem is that
the definitions of concussion put forth by ICD-10 and DSM-IV are inadequate. Specifically,
ICD-10 requires a loss of consciousness (LOC), yet national and international
definitions (including one later adapted by the World Health Organization,
which is responsible for ICD-10) clearly states that LOC is not required for a
concussion diagnosis. Strict adherence to the ICD-10 criteria would result in
removing vast numbers of patients who were concussed (but who did not lose
consciousness) from being eligible for the diagnosis.
Although DSM-IV does not
restrict concussions to those who experienced LOC, the criteria only lists a few
manifestations of concussion and does not provide a precise definition.
Regardless, both criteria sets make it clear that it needs to be established
that a patient suffered a concussion before a diagnosis of PCS or PCD can be
made. In clinical practice, however, I have seen many cases where patients who
suffered head injuries (yet do not meet operational definition for MTBI) are
diagnosed with “post concussion syndrome.” This would be akin to saying that
you are having a post-game show without having a game first. It does not make
sense.
What to do from here?
Boake et al. (2005)
noted that “…further refinement of the DSM-IV and ICD-10 criteria for PCS is
needed before these criteria are routinely employed.” My opinion is to
avoid use of these terms entirely because the criteria by which they are based
upon are too flawed and were only designed for research purposes. Using a term
that has no criteria associated with it such as “post concussion syndrome” does
not solve the problem either. What most people mean when they use this term is
that the patient had a history of a concussion followed by numerous symptoms.
However, as was noted earlier by the Iverson (2006) study and in the review by
McCrea (2008) such a standard is too non-specific to brain injury and
overly-inclusive. This is a significant problem because patients will interpret
the term as meaning that all of their symptoms are caused by brain injury when
this is likely not the case.
While the patient may
feel better initially when receiving a diagnosis of PCS because it provides
medical validation he/she has been seeking, it can also make the situation far
worse in the long run because other potentially treatable conditions such as posttraumatic stress disorder, major depressive disorder, personality disorders, as well as
psychosocial factors may not be recognized as contributory, causing the patient
to continue to suffer with symptoms far longer than is needed.
My advice to physicians,
nurse practitioners, non-neuropsychologists, and other front-line health care
providers dealing with patients more than three months post-injury is to
document the medical history in the note, state whether there appears to be a
history of head injury or MTBI (if appropriately trained to assess this) and to
then state that the patient is experiencing persistent symptoms but that the
cause is unclear and needs to be further evaluated through a neuropsychological evaluation. A rule out diagnosis of cognitive disorder NOS can be listed
for billing purposes. It should be explained to the patient that the cause of
the symptoms are unclear and that further evaluation is needed to determine
this.
Disclaimer: The author of this entry is a board certified clinical neuropsychologist..
REFERENCES
American Psychiatric
Association (1994). Diagnostic and Statistical Manual of Mental Disorders,
Fourth Edition. Washington,
DC, American Psychiatric
Association.
Belanger et al. (2005a).
The neuropsychological impact of sports-related concussion: A meta-analysis.
Journal of the International Neuropsychological Society, 11, 345–357.
Belanger et al. (2005b).
Factors moderating neuropsychological outcomes following mild traumatic brain
injury: a meta-analysis. Journal of the International Neuropsychological
Society, 11, 215-27.
Binder, L.M. et al.
(1997a). A review of mild head trauma. Part I: meta-analytic review of
neuropsychological studies. Journal of Clinical and Experimental
Neuropsychology, 19, 421–431.
Binder, L.M. et al.
(1997b). A review of mild head trauma. Part II: clinical implications. Journal
of Clinical and Experimental Neuropsychology, 19, 432–457.
Bleiberg, J. Duration of
cognitive impairment after sports concussion. Neurosurgery, 54, 1073-80.
Boake et al. (2004).
Limited Agreement Between Criteria-Based Diagnoses of Postconcussional
Syndrome. The Journal ofNeur opsychiatry and Clinical Neurosciences, 16,
493–499.
Boake et al. (2005).
Diagnostic Criteria for Postconcussional Syndrome After Mild to Moderate
Traumatic Brain Injury. The Journal of Neuropsychiatry and Clinical
Neurosciences 2005; 17:350–356.
Dikmen, S.S. (1995).
Neuropsychological outcome at one-year post head injury. Neuropsychology, 9,
80–90.
Frenchman, K.A. et al.
(2005). Neuropsychological studies of mild traumatic brain injury : a
meta-analytic review of research since 1995. Journal of Clinical and
Experimental Neuropsychology, 27, 334-51.
Iverson, G. (2006).
Misdiagnosis of the persistent postconcussion syndrome in patients with
depression. Archives of Clinical Neuropsychology 21, 303–310
Iverson, G. (2005).
Outcome from mild traumatic brain injury. Current Opinion in Psychiatry, 18,
301–317.
Larrabee, G. (1997).
Neuropsychological outcome, post concussion symptoms, and forensic
considerations in mild closed head trauma. Seminars in Clinical
Neuropsychiatry, 2, 196-206.
McCrea, M. (2008). Mild
traumatic brain injury and postconcussion syndrome. The new evidence base for
diagnosis and treatment. New York: Oxford University
Press.
Mittenberg et al.
(1992). Symptoms following mild head injury: Expectation as aetiology. Journal
of Neurology, Neurosurgery, and Psychiatry, 55, 200-4.
Pellman et al. (2004).
Concussion in Professional Football: Neuropsychological Testing - part 6.
Neurosurgery, 55, 1290-1305.
Polam et al. (2005).
Diagnostic criteria for multiple sclerosis: 2005 revisions to the McDonald
criteria. Ann Neurol. 58; 840-846.
Schretlen et al. (2003).
A quantitative review of the effects of traumatic brain injury on cognitive
functioning. International Review of Psychiatry, 15, 341–349.
World Health
Organization (1992). International statistical classification of diseases and
related health problems - 10th edition. Geneva,
Switzerland:
World Health Organization.
Appendix
A
ICD-10 Definition:
Post-concussional syndrome
Listed below are the
diagnostic criteria for PCS from ICD-10.
“Note: The nosological
status of this syndrome is uncertain, and criterion A of the introduction to
this rubric is not always ascertainable. However, for those undertaking
research into this condition, the following criteria are recommended:
A. The general criteria
of F07 must be met. The general criteria for F07, Personality and Behavioral
Disorders Due to Brain Disease, Damage and Dysfunction, are as follows:
G1. Objective evidence
(from physical and neurological examination and laboratory tests) and/or
history, of cerebral disease, damage, or dysfunction.
G2. Absence of clouding
of consciousness and of significant memory deficit.
G3. Absence of
sufficient or suggestive evidence for an alternative causation of the
personality or behavior disorder that would justify its placement in section F6
(Other Mental Disorders Due to Brain Damage and Dysfunction and to Physical
Disease).
B. History of head
trauma with loss of consciousness, preceding the onset of symptoms by a period
of up to four weeks (objective EEG, brain imaging, or oculonystagmographic
evidence for brain damage may be lacking).
C. At least three of the
following:
(1) Complaints of
unpleasant sensations and pains, such as headache, dizziness (usually lacking
the features of true vertigo), general malaise and excessive fatigue, or noise
intolerance.
(2) Emotional changes, such as irritability, emotional lability, both easily
provoked or exacerbated by emotional excitement or stress, or some degree of
depression and/or anxiety.
(3) Subjective complaints of difficulty in concentration and in performing
mental tasks, and of memory complaints, without clear objective evidence (e.g.
psychological tests) of marked impairment.
(4) Insomnia.
(5) Reduced tolerance to alcohol.
(6) Preoccupation with the above symptoms and fear of permanent brain damage,
to the extent of hypochondriacal over-valued ideas and adoption of a sick role.
DSM-IV Definition:
Post-concussional disorder
A. A history of head
trauma that has caused a significant cerebral concussion.
Note. The manifestations
of concussion include loss of consciousness, post-traumatic amnesia, and less
commonly, post-traumatic onset of seizures. Specific approaches for defining
this criterion need to be refined by further research.
B. Evidence from
neuropsychological testing or quantified cognitive assessment of difficulty in
attention (concentrating, shifting focus of attention, performing simultaneous
cognitive tasks) or memory.
C. Three (or more) of
the following occur shortly after the trauma and last at least 3 months.
1. becoming fatigued
easily (2) disordered sleep (3) headache (4) vertigo or dizziness, (5) irritability
or aggression on little or no provocation, (6) anxiety, depression, or
affective liability (7) changes in personality (e.g., social or sexual
inappropriateness) (8) apathy or lack of spontaneity.
D. The symptoms in
criteria B or C have their onset following head trauma or else represent a
substantial worsening of preexisting symptoms.
E. The disturbance
causes significant impairment in social or occupational functioning and
represents a significant decline from a previous level of functioning. In school
age children, the impairment may be manifested by a significant worsening in
school or academic performance dating from the trauma.
F. The symptoms do not
meet criteria for Dementia due to Head Trauma and are not better accounted for
by another mental disorder (e.g., Amnestic Disorder due to Head Trauma,
Personality Change Due to Head Trauma.